Q.1 What is the primary definition of a biomaterial?
A material that is synthesized by living organisms
A material that can be used to replace or augment a biological function
A material that conducts electricity better than copper
A material that is always biodegradable
Explanation - Biomaterials are engineered substances designed to interact with biological systems for therapeutic or diagnostic purposes.
Correct answer is: A material that can be used to replace or augment a biological function
Q.2 Which property is most critical for a biomaterial used in neural electrodes?
High thermal conductivity
Low electrical resistance and biocompatibility
High optical reflectivity
Strong magnetic susceptibility
Explanation - Neural electrodes must conduct electrical signals efficiently while not causing adverse tissue reactions.
Correct answer is: Low electrical resistance and biocompatibility
Q.3 Polypyrrole (PPy) is an example of:
A metallic alloy
A conductive polymer
A ceramic material
A natural protein
Explanation - Polypyrrole is a synthetic polymer that exhibits electrical conductivity, making it useful in bioelectronic devices.
Correct answer is: A conductive polymer
Q.4 Which of the following is NOT a typical classification of biomaterials?
Metallic
Polymeric
Ceramic
Superconductive
Explanation - While some biomaterials may exhibit superconductivity at low temperatures, it is not a standard classification category.
Correct answer is: Superconductive
Q.5 What does the term 'biocompatibility' refer to?
The ability of a material to dissolve in water
The ability of a material to perform its desired function without eliciting any undesirable local or systemic effects in the recipient
The electrical conductivity of a material in biological fluids
The mechanical strength of a material under physiological loads
Explanation - Biocompatibility is a measure of how well a material integrates with the body without causing toxicity or inflammation.
Correct answer is: The ability of a material to perform its desired function without eliciting any undesirable local or systemic effects in the recipient
Q.6 Which biomaterial is commonly used for cardiac pacemaker leads because of its flexibility and conductivity?
Silicone rubber
Stainless steel
Polyethylene terephthalate (PET)
Gold-plated polyimide
Explanation - Gold-plated polyimide combines flexibility with excellent conductivity and corrosion resistance, ideal for pacemaker leads.
Correct answer is: Gold-plated polyimide
Q.7 The process of sterilizing biomaterials using high-energy radiation is known as:
Autoclaving
Gamma irradiation
Cryogenic freezing
Electroplating
Explanation - Gamma irradiation penetrates deep into materials and destroys microorganisms without leaving residue, making it suitable for many biomaterials.
Correct answer is: Gamma irradiation
Q.8 Which electrical property is most important for a material used in a cochlear implant electrode array?
Dielectric constant
Capacitance
Charge injection capacity
Magnetic permeability
Explanation - High charge injection capacity allows efficient stimulation of auditory nerve fibers without causing tissue damage.
Correct answer is: Charge injection capacity
Q.9 Hydrogel biomaterials are primarily characterized by:
High electrical conductivity
High water content and soft mechanical properties
Metallic luster
Magnetic properties
Explanation - Hydrogels are polymer networks that can retain large amounts of water, mimicking soft tissue environments.
Correct answer is: High water content and soft mechanical properties
Q.10 Which of the following biomaterials exhibits piezoelectric behavior useful for bone regeneration?
Titanium alloy
Poly(lactic acid)
Barium titanate
Silicone
Explanation - Barium titanate is a ceramic that generates electrical charge under mechanical stress, stimulating bone growth.
Correct answer is: Barium titanate
Q.11 What is the main advantage of using biodegradable polymers like polylactic acid (PLA) in temporary implants?
Unlimited mechanical strength
Elimination of second surgery for removal
Infinite electrical conductivity
Resistance to all bacterial infections
Explanation - Biodegradable polymers gradually break down into non‑toxic by‑products, removing the need for surgical extraction.
Correct answer is: Elimination of second surgery for removal
Q.12 In bioelectronic interfaces, the term ‘impedance’ refers to:
The resistance of blood flow through a vessel
The opposition to alternating current flow at the electrode–tissue interface
The mechanical stiffness of a biomaterial
The thermal conductivity of a polymer
Explanation - Impedance combines resistive and capacitive effects and influences signal quality in neural recordings.
Correct answer is: The opposition to alternating current flow at the electrode–tissue interface
Q.13 Which material is frequently used as a coating to improve the biocompatibility of metallic implants?
Hydroxyapatite
Copper
Aluminum oxide
Polystyrene
Explanation - Hydroxyapatite mimics bone mineral and encourages osseointegration when applied as a coating on metals.
Correct answer is: Hydroxyapatite
Q.14 The term ‘electroactive biomaterial’ best describes:
A material that changes shape in response to electric fields
A material that is completely inert in the body
A material that only conducts heat
A material that degrades instantly in water
Explanation - Electroactive biomaterials can respond to electrical stimulation, useful for actuators and drug delivery.
Correct answer is: A material that changes shape in response to electric fields
Q.15 Which of the following is a major challenge when integrating electronic circuitry with soft biomaterials?
Achieving high optical transparency
Matching mechanical compliance to avoid tissue damage
Increasing magnetic susceptibility
Reducing thermal expansion to zero
Explanation - Rigid electronics can cause chronic inflammation; therefore, flexibility and matching tissue stiffness are crucial.
Correct answer is: Matching mechanical compliance to avoid tissue damage
Q.16 What does the term ‘biofouling’ refer to in the context of implantable sensors?
The corrosion of metal components
The accumulation of biological material on sensor surfaces, impairing function
The rapid degradation of polymeric encapsulation
The increase in electrical conductivity over time
Explanation - Biofouling can block sensor interfaces, leading to drift or loss of signal.
Correct answer is: The accumulation of biological material on sensor surfaces, impairing function
Q.17 Which of these materials is known for its high charge storage capacity and is used in retinal prostheses?
Iridium oxide (IrOx)
Aluminum foil
Polyvinyl chloride (PVC)
Silicon carbide
Explanation - IrOx offers excellent charge injection properties while being biocompatible, suitable for stimulating retinal cells.
Correct answer is: Iridium oxide (IrOx)
Q.18 The 'glass transition temperature' (Tg) of a polymer biomaterial is important because:
It determines the temperature at which the polymer becomes electrically conductive
It indicates the temperature where the polymer changes from a brittle to a rubbery state, affecting flexibility
It is the temperature at which the polymer melts completely
It defines the magnetic properties of the polymer
Explanation - Tg influences mechanical behavior at body temperature; polymers with Tg below body temperature are more flexible.
Correct answer is: It indicates the temperature where the polymer changes from a brittle to a rubbery state, affecting flexibility
Q.19 Which method is most commonly used to assess the cytotoxicity of a new biomaterial?
Four‑point bend test
MTT assay
X‑ray diffraction
Fourier‑transform infrared spectroscopy
Explanation - The MTT assay measures cell metabolic activity and is a standard test for cytotoxicity.
Correct answer is: MTT assay
Q.20 In the context of bioelectronics, ‘soft lithography’ is primarily used for:
Creating rigid metal molds
Patterning microstructures on flexible polymer substrates
Measuring electrical conductivity
Heat treating ceramics
Explanation - Soft lithography uses elastomeric stamps to transfer patterns onto soft, often biocompatible, substrates.
Correct answer is: Patterning microstructures on flexible polymer substrates
Q.21 Which property of a biomaterial primarily determines its ability to support cell adhesion?
Electrical conductivity
Surface energy and chemistry
Thermal conductivity
Magnetic permeability
Explanation - High surface energy and specific chemical groups promote protein adsorption and subsequent cell attachment.
Correct answer is: Surface energy and chemistry
Q.22 What is the main advantage of using carbon nanotubes (CNTs) in neural interfacing?
They are biodegradable within a week
They provide high mechanical strength and excellent electrical conductivity with a small footprint
They are magnetic and can be guided by external fields
They have a high optical reflectivity
Explanation - CNTs can create ultra‑thin, flexible, and highly conductive pathways for neural recording and stimulation.
Correct answer is: They provide high mechanical strength and excellent electrical conductivity with a small footprint
Q.23 Which of the following is a common technique to improve the electrical interface between a metal electrode and neural tissue?
Electropolishing
Applying a thin layer of silicone
Embedding the electrode in bone cement
Coating with gold nanoparticles
Explanation - Gold nanoparticles increase surface area and reduce impedance, enhancing signal quality.
Correct answer is: Coating with gold nanoparticles
Q.24 The term ‘bioresorbable’ refers to a biomaterial that:
Conducts electricity without any loss
Can be absorbed by the body over time and safely eliminated
Never degrades under physiological conditions
Generates magnetic fields inside tissue
Explanation - Bioresorbable materials are designed to degrade into biocompatible products, eliminating long‑term foreign body presence.
Correct answer is: Can be absorbed by the body over time and safely eliminated
Q.25 Which of the following is an example of a metallic biomaterial commonly used for orthopedic implants?
Titanium alloy (Ti‑6Al‑4V)
Polyethylene
Silicone elastomer
Polymethyl methacrylate (PMMA)
Explanation - Titanium alloys offer high strength, corrosion resistance, and good biocompatibility for load‑bearing applications.
Correct answer is: Titanium alloy (Ti‑6Al‑4V)
Q.26 In biomaterials, ‘hydrophobicity’ of a surface generally leads to:
Increased protein adsorption
Reduced cell adhesion and lower biofouling
Higher electrical conductivity
Faster degradation in water
Explanation - Hydrophobic surfaces repel water and proteins, discouraging cell attachment and microbial colonization.
Correct answer is: Reduced cell adhesion and lower biofouling
Q.27 Which of the following best describes a 'smart' biomaterial?
A material that changes its properties in response to an external stimulus
A material that is always rigid and inert
A material that cannot be sterilized
A material that only works at cryogenic temperatures
Explanation - Smart biomaterials can respond to pH, temperature, electric fields, or other signals to perform a function.
Correct answer is: A material that changes its properties in response to an external stimulus
Q.28 The main purpose of using a ‘passivation layer’ on silicon‑based implantable electronics is to:
Increase the optical transparency
Prevent corrosion and isolate the circuitry from body fluids
Make the device magnetic
Reduce the device’s weight
Explanation - Passivation layers such as silicon nitride or parylene protect electronic components from the harsh ionic environment of the body.
Correct answer is: Prevent corrosion and isolate the circuitry from body fluids
Q.29 Which polymer is widely used for making soft, stretchable electrodes for wearable health monitors?
Polydimethylsiloxane (PDMS)
Polyvinyl chloride (PVC)
Polyethylene terephthalate (PET)
Polycarbonate (PC)
Explanation - PDMS is elastomeric, biocompatible, and can be patterned with conductive inks for flexible electronics.
Correct answer is: Polydimethylsiloxane (PDMS)
Q.30 What is the function of a ‘conductive hydrogel’ in bioelectronic devices?
To provide a rigid support structure
To enable ionic conduction while matching tissue softness
To block all electrical signals
To act as a magnetic shield
Explanation - Conductive hydrogels allow charge transport through ions and conform to soft tissue, improving interface quality.
Correct answer is: To enable ionic conduction while matching tissue softness
Q.31 Which of the following is a common degradation pathway for polyester‑based biodegradable polymers such as PLA?
Oxidative degradation by free radicals
Hydrolytic cleavage of ester bonds
Thermal melting above 300 °C
Photolytic breakdown under visible light
Explanation - Water molecules hydrolyze the ester linkages in PLA, leading to gradual degradation into lactic acid.
Correct answer is: Hydrolytic cleavage of ester bonds
Q.32 In the context of implantable devices, ‘drift’ of a sensor signal most often results from:
Changes in ambient temperature only
Biofouling and encapsulation of the sensor surface
Variations in power supply voltage only
Fluctuations in the Earth's magnetic field
Explanation - Tissue encapsulation and protein buildup alter the sensor’s electrical properties, causing signal drift.
Correct answer is: Biofouling and encapsulation of the sensor surface
Q.33 Which characteristic of a biomaterial influences its ‘Young’s modulus’?
Electrical resistivity
Molecular weight of the polymer
Cross‑link density of the polymer network
Optical refractive index
Explanation - Higher cross‑link density typically increases stiffness, raising the Young’s modulus.
Correct answer is: Cross‑link density of the polymer network
Q.34 A ‘bio‑MEMS’ device typically combines:
Macro‑scale mechanical parts with chemical sensors
Micro‑electromechanical systems and biological functionality
Large metal plates with magnetic actuators
Optical fibers with thermal sensors
Explanation - Bio‑MEMS integrate microscale mechanical components with biocompatible materials for sensing or actuation in biological environments.
Correct answer is: Micro‑electromechanical systems and biological functionality
Q.35 Which property is critical for a biomaterial used in a pacemaker’s battery housing?
High dielectric strength to prevent short circuits
Transparency to visible light
Magnetic permeability greater than 1000
Low melting point
Explanation - The housing must insulate the battery from bodily fluids and prevent electrical leakage.
Correct answer is: High dielectric strength to prevent short circuits
Q.36 What is the main reason gold is often used as a coating material for implantable electrodes?
It is the cheapest metal available
It has excellent biocompatibility and resists corrosion
It is magnetic and can be manipulated externally
It dissolves quickly in physiological fluids
Explanation - Gold is inert, does not trigger immune responses, and maintains conductivity over long periods.
Correct answer is: It has excellent biocompatibility and resists corrosion
Q.37 Which biomaterial property is most directly related to its ability to conduct ionic currents?
Dielectric constant
Water content
Thermal conductivity
Elastic modulus
Explanation - Ionic conduction occurs through mobile ions in aqueous environments; higher water content facilitates this process.
Correct answer is: Water content
Q.38 In tissue engineering scaffolds, the term ‘porosity’ is important because:
It determines the scaffold’s color
Higher porosity improves nutrient diffusion and cell infiltration
It makes the scaffold magnetic
It reduces the electrical resistance to zero
Explanation - Adequate pore size and interconnectivity allow cells to migrate and receive nutrients, supporting tissue growth.
Correct answer is: Higher porosity improves nutrient diffusion and cell infiltration
Q.39 Which of the following statements about ‘electrospinning’ is correct?
It creates large, solid metal rods
It produces nanofibrous mats that can be used as biomimetic scaffolds
It is a technique for measuring electrical resistance
It is used to sterilize biomaterials
Explanation - Electrospinning uses an electric field to draw polymer solutions into ultrafine fibers, forming porous meshes.
Correct answer is: It produces nanofibrous mats that can be used as biomimetic scaffolds
Q.40 Which material is often employed as an insulating layer in flexible bioelectronic patches?
Silicon dioxide (SiO₂)
Polyimide (PI)
Copper
Aluminum
Explanation - Polyimide combines flexibility, thermal stability, and excellent dielectric properties, making it suitable for stretchable devices.
Correct answer is: Polyimide (PI)
Q.41 The ‘Stokes–Einstein equation’ is useful for estimating:
Electrical conductivity of metals
Diffusion coefficient of particles in a fluid, which can affect drug release from biomaterials
Magnetic field strength inside tissue
Thermal conductivity of ceramics
Explanation - It relates particle size, temperature, and fluid viscosity to diffusion rate, relevant for controlled release systems.
Correct answer is: Diffusion coefficient of particles in a fluid, which can affect drug release from biomaterials
Q.42 What advantage does a ‘nanocomposite’ biomaterial offer over a conventional polymer?
It always becomes magnetic
Enhanced mechanical, electrical, or antibacterial properties due to the inclusion of nanofillers
It is automatically biodegradable
It eliminates the need for sterilization
Explanation - Nanoparticles (e.g., silver, graphene) can dramatically modify the host polymer’s performance.
Correct answer is: Enhanced mechanical, electrical, or antibacterial properties due to the inclusion of nanofillers
Q.43 Which of the following is a key consideration when designing a biodegradable stent?
The stent must never lose its mechanical strength
The degradation rate must match the healing timeline of the vessel
The stent should be magnetic for easy retrieval
The stent must be opaque to X‑rays
Explanation - If the stent degrades too quickly, the vessel may collapse; too slowly, it may cause chronic inflammation.
Correct answer is: The degradation rate must match the healing timeline of the vessel
Q.44 In the context of biomaterials, ‘anisotropy’ refers to:
Uniform properties in all directions
Properties that vary depending on direction, such as mechanical strength
Ability to conduct electricity only at high frequencies
Complete resistance to any chemical reaction
Explanation - Anisotropic materials have direction‑dependent characteristics, important for mimicking native tissue behavior.
Correct answer is: Properties that vary depending on direction, such as mechanical strength
Q.45 Which of the following metals is most commonly alloyed with vanadium to improve its corrosion resistance for orthopedic implants?
Aluminum
Zirconium
Nickel
Titanium
Explanation - Ti‑6Al‑4V (titanium alloy with 6% aluminum and 4% vanadium) offers excellent strength and corrosion resistance.
Correct answer is: Aluminum
Q.46 A ‘conductive polymer’ used in neural probes typically exhibits which type of charge transport?
Electronic conduction through delocalized π‑electrons
Ionic conduction via water molecules
Proton conduction only at low pH
Thermal conduction only
Explanation - Conductive polymers like polypyrrole have conjugated π‑electron systems enabling electronic conductivity.
Correct answer is: Electronic conduction through delocalized π‑electrons
Q.47 What is the main purpose of a ‘sacrificial layer’ in the fabrication of bio‑MEMS devices?
To provide structural strength during implantation
To be removed later, creating channels or cavities within the device
To act as the final encapsulating coating
To increase the device’s weight
Explanation - Sacrificial layers are etched away after device formation, leaving micro‑features such as fluidic channels.
Correct answer is: To be removed later, creating channels or cavities within the device
Q.48 Which of the following best describes ‘electrochemical impedance spectroscopy’ (EIS) in biomaterial testing?
A method to measure the magnetic field of a device
A technique to evaluate the frequency‑dependent impedance of an electrode–tissue interface
A way to assess the optical transparency of polymers
A process for sterilizing implants
Explanation - EIS provides insight into resistive and capacitive elements of the interface, critical for device performance.
Correct answer is: A technique to evaluate the frequency‑dependent impedance of an electrode–tissue interface
Q.49 The term ‘mechanotransduction’ in biomaterials refers to:
Conversion of mechanical stimuli into electrical signals by cells interacting with a material
The ability of a material to melt under pressure
The magnetic response of a polymer
The degradation of a material due to heat
Explanation - Mechanotransduction is essential for designing scaffolds that can influence cell behavior through mechanical cues.
Correct answer is: Conversion of mechanical stimuli into electrical signals by cells interacting with a material
Q.50 Which of the following is a common anti‑bacterial additive used in biomaterials for implant coatings?
Silver nanoparticles
Copper foil
Gold leaf
Aluminium powder
Explanation - Silver has broad‑spectrum antimicrobial activity and can be incorporated into coatings to prevent infection.
Correct answer is: Silver nanoparticles
Q.51 In a bio‑resorbable electronic device, why is magnesium often selected as a conductive element?
It is non‑conductive but biodegradable
It degrades into harmless ions while maintaining conductivity during its functional lifespan
It never degrades in the body
It is magnetic and can be guided by external fields
Explanation - Magnesium offers good conductivity and bio‑compatible degradation products (Mg²⁺), making it suitable for transient electronics.
Correct answer is: It degrades into harmless ions while maintaining conductivity during its functional lifespan
Q.52 What is the primary benefit of using ‘laser‑induced graphene’ on flexible polymer substrates for biosensing?
Creates a transparent coating
Produces a highly conductive, porous graphene network directly on the substrate
Makes the substrate magnetic
Increases the substrate’s melting point
Explanation - Laser patterning converts polymer carbon into graphene, enabling low‑cost, flexible, high‑surface‑area electrodes.
Correct answer is: Produces a highly conductive, porous graphene network directly on the substrate
Q.53 Which of the following best explains why surface roughness can improve the performance of an implantable electrode?
It reduces the electrode’s electrical resistance to zero
It increases surface area, lowering impedance and enhancing charge transfer
It makes the electrode magnetic
It prevents any protein adsorption
Explanation - Rough surfaces provide more contact points for ion exchange, improving signal quality.
Correct answer is: It increases surface area, lowering impedance and enhancing charge transfer
Q.54 Which biomaterial is most appropriate for a long‑term sub‑dermal glucose sensor that requires high optical clarity?
Silicone elastomer
Polyethylene terephthalate (PET)
Polyimide
Parylene C
Explanation - PET is optically transparent, biocompatible, and provides a stable barrier for optical sensing.
Correct answer is: Polyethylene terephthalate (PET)
Q.55 What is the purpose of ‘cross‑linking’ in polymeric biomaterials?
To make the polymer soluble in water
To increase mechanical strength and control degradation rate
To reduce the polymer’s density
To make the polymer magnetic
Explanation - Cross‑linking creates covalent bonds between polymer chains, enhancing stiffness and slowing hydrolysis.
Correct answer is: To increase mechanical strength and control degradation rate
Q.56 Which property of a material most directly influences its 'electrochemical window' when used as an electrode?
Thermal conductivity
Water content
Electrode material’s stability against oxidation/reduction
Magnetic permeability
Explanation - The electrochemical window is the potential range where the electrode material remains chemically stable.
Correct answer is: Electrode material’s stability against oxidation/reduction
Q.57 Which biomaterial is commonly used for drug‑eluting stents to control release kinetics?
Poly(lactic‑co‑glycolic acid) (PLGA)
Silicon carbide
Copper wire
Glass fiber
Explanation - PLGA degrades predictably, allowing controlled drug release over weeks to months.
Correct answer is: Poly(lactic‑co‑glycolic acid) (PLGA)
Q.58 The term ‘bio‑integration’ most accurately describes:
The process of a biomaterial being completely rejected by the body
The seamless functional and structural connection between the implant and surrounding tissue
The conversion of a biomaterial into bone tissue
The magnetic coupling of a device with tissue
Explanation - Bio‑integration implies that the host tissue accepts the implant without chronic inflammation and forms a stable interface.
Correct answer is: The seamless functional and structural connection between the implant and surrounding tissue
Q.59 Which of the following is a typical method to enhance the adhesion of a polymer coating to a metallic substrate?
Polishing with a diamond tip
Applying a thin adhesion promoter layer such as silane coupling agents
Heating the metal above its melting point
Immersing the metal in water
Explanation - Silane agents form chemical bonds with both metal oxides and polymers, improving interfacial adhesion.
Correct answer is: Applying a thin adhesion promoter layer such as silane coupling agents
Q.60 What advantage does a ‘self‑healing’ biomaterial provide for implantable electronics?
It can repair micro‑cracks, prolonging device lifespan
It becomes magnetic after healing
It instantly dissolves after use
It makes the device opaque
Explanation - Self‑healing polymers can re‑form bonds after damage, maintaining mechanical integrity and barrier properties.
Correct answer is: It can repair micro‑cracks, prolonging device lifespan
Q.61 Which analytical technique is most suitable for measuring the surface roughness of an electrode intended for neural recording?
Scanning electron microscopy (SEM)
X‑ray diffraction (XRD)
Fourier‑transform infrared spectroscopy (FTIR)
Thermogravimetric analysis (TGA)
Explanation - SEM provides high‑resolution images that can be quantified for surface topography.
Correct answer is: Scanning electron microscopy (SEM)
Q.62 In the design of a bio‑electronic patch for cardiac monitoring, which property is essential to prevent motion artifacts?
High Young’s modulus
Low viscoelastic damping
Conformal adhesion and appropriate flexibility
High magnetic susceptibility
Explanation - A flexible patch that conforms to skin motion reduces relative movement and improves signal fidelity.
Correct answer is: Conformal adhesion and appropriate flexibility
Q.63 Which of the following biomaterials is inherently piezoelectric and can be used for energy harvesting from body movements?
Poly(vinylidene fluoride) (PVDF)
Polystyrene (PS)
Polyethylene (PE)
Silicone rubber
Explanation - PVDF exhibits strong piezoelectricity, converting mechanical strain into electrical charge.
Correct answer is: Poly(vinylidene fluoride) (PVDF)
Q.64 The ‘Hounsfield unit’ is a measure used in medical imaging. In the context of biomaterials, it is most directly related to:
Electrical conductivity
Radiodensity of the material in CT scans
Thermal conductivity
Magnetic susceptibility
Explanation - Hounsfield units quantify X‑ray attenuation, useful for visualizing implants in CT images.
Correct answer is: Radiodensity of the material in CT scans
Q.65 Which property of a biomaterial would most directly affect the rate at which a drug diffuses out of a polymeric carrier?
Electrical resistivity
Polymer cross‑link density
Magnetic permeability
Optical clarity
Explanation - Higher cross‑link density reduces free volume, slowing diffusion of encapsulated drugs.
Correct answer is: Polymer cross‑link density
Q.66 In a bio‑MEMS pressure sensor, the sensing element is often made from:
Silicon diaphragm coated with a biocompatible layer
Copper wire coil
Gold foil
Aluminium block
Explanation - Silicon diaphragms provide precise mechanical deflection; coating ensures biocompatibility and protection.
Correct answer is: Silicon diaphragm coated with a biocompatible layer
Q.67 Which of the following describes the ‘burst release’ phenomenon in drug‑eluting biomaterials?
A sudden, high‑rate release of drug shortly after implantation
A slow, constant release over years
Complete lack of drug release
Release only when an external magnetic field is applied
Explanation - Burst release can cause toxicity; formulation strategies aim to minimize it.
Correct answer is: A sudden, high‑rate release of drug shortly after implantation
Q.68 Which material is commonly used as a flexible, transparent encapsulant for organic bioelectronics?
Parylene C
Stainless steel
Titanium alloy
Aluminum oxide
Explanation - Parylene C forms a pinhole‑free, conformal coating that is both flexible and optically clear.
Correct answer is: Parylene C
Q.69 What is the primary function of a ‘titanium nitride (TiN)’ coating on neural microelectrodes?
To make the electrode magnetic
To increase surface area and lower impedance while improving biocompatibility
To make the electrode biodegradable
To change the electrode color to green
Explanation - TiN is a hard, conductive ceramic that reduces impedance and resists corrosion.
Correct answer is: To increase surface area and lower impedance while improving biocompatibility
Q.70 Which of the following best explains why the ‘Debye length’ is important in the design of bio‑electrodes?
It determines the magnetic field strength of the electrode
It indicates the distance over which charge screening occurs in electrolyte solutions, influencing electrode–tissue coupling
It defines the optical wavelength the electrode can detect
It measures the thermal conductivity of the material
Explanation - The Debye length (~1 nm in physiological saline) affects how electric fields decay near the electrode surface.
Correct answer is: It indicates the distance over which charge screening occurs in electrolyte solutions, influencing electrode–tissue coupling
Q.71 Which polymer is often used as a sacrificial layer that can be removed with water in microfabrication of bio‑MEMS?
Polyvinyl alcohol (PVA)
Polystyrene (PS)
Polycarbonate (PC)
Polyethylene terephthalate (PET)
Explanation - PVA is water‑soluble, allowing gentle removal without damaging surrounding structures.
Correct answer is: Polyvinyl alcohol (PVA)
Q.72 In a bio‑electronic implant, why is it important to control the ‘charge density’ delivered during electrical stimulation?
To avoid heating the tissue
To prevent irreversible electrochemical reactions that can damage tissue
To make the device invisible to MRI
To increase magnetic resonance signals
Explanation - Excessive charge density can cause water electrolysis and tissue injury.
Correct answer is: To prevent irreversible electrochemical reactions that can damage tissue
Q.73 Which material property is most critical for a biomaterial intended for a retinal prosthesis that must transmit light?
High optical transparency
High magnetic permeability
Low Young’s modulus
High thermal conductivity
Explanation - Light must reach the photoreceptor layer; a transparent substrate ensures efficient photon delivery.
Correct answer is: High optical transparency
Q.74 What is the main reason for using ‘micro‑patterned’ surfaces on bone‑integrating implants?
To increase magnetic attraction
To promote cell alignment and osseointegration by mimicking natural bone topography
To make the implant electrically insulating
To reduce the implant’s weight
Explanation - Micro‑features guide osteoblasts and improve mechanical interlocking with bone.
Correct answer is: To promote cell alignment and osseointegration by mimicking natural bone topography
Q.75 Which of the following is a standard test to evaluate the hemocompatibility of a cardiovascular biomaterial?
Platelet adhesion assay
Four‑point bend test
Thermal gravimetric analysis
Magnetic resonance imaging
Explanation - Assessing platelet adhesion and activation determines the risk of thrombosis on the material surface.
Correct answer is: Platelet adhesion assay
Q.76 In bio‑electronics, the term ‘faradaic process’ refers to:
Purely capacitive charge storage
Charge transfer involving redox reactions at the electrode–electrolyte interface
Magnetic induction
Thermal heating of the electrode
Explanation - Faradaic currents involve electron exchange and can be used for stimulation but may cause electrode degradation.
Correct answer is: Charge transfer involving redox reactions at the electrode–electrolyte interface
Q.77 Which of the following materials can be used to fabricate a biodegradable wireless power receiver for implantable devices?
Silicon nanowires coated with magnesium
Stainless steel
Gold foil
Aluminum oxide
Explanation - Silicon provides semiconducting properties while magnesium offers biodegradable conductivity, enabling transient wireless power harvesting.
Correct answer is: Silicon nanowires coated with magnesium
Q.78 What is the main purpose of a ‘hydrogel‑based ionic conductor’ in a soft neural interface?
To act as a rigid barrier
To provide a low‑impedance, tissue‑like pathway for ionic current
To generate magnetic fields
To reflect light
Explanation - Hydrogel conductors match the ionic conductivity of extracellular fluid, reducing interface impedance.
Correct answer is: To provide a low‑impedance, tissue‑like pathway for ionic current
Q.79 Which of the following statements about ‘bio‑inert’ materials is correct?
They actively promote cell growth
They do not elicit any significant biological response and are often used where long‑term stability is required
They dissolve quickly in body fluids
They generate electrical currents spontaneously
Explanation - Bio‑inert materials like titanium and certain ceramics are chemically stable and minimize immune reactions.
Correct answer is: They do not elicit any significant biological response and are often used where long‑term stability is required
Q.80 Which measurement technique would you use to assess the dielectric constant of a polymer intended for an implantable capacitor?
LCR meter (impedance analyzer)
Scanning electron microscopy (SEM)
X‑ray diffraction (XRD)
Thermogravimetric analysis (TGA)
Explanation - An LCR meter can determine capacitance and loss, from which the dielectric constant is derived.
Correct answer is: LCR meter (impedance analyzer)
Q.81 What advantage does a ‘graphene oxide (GO) coating’ provide for a neural electrode?
It makes the electrode magnetic
It improves charge injection capacity and provides a biocompatible surface
It reduces the electrode’s size to atomic dimensions
It causes rapid degradation of the electrode
Explanation - GO offers high surface area and functional groups that enhance adhesion and electrochemical performance.
Correct answer is: It improves charge injection capacity and provides a biocompatible surface
Q.82 Which of the following is a common cause of mechanical failure in chronic implantable devices?
Thermal expansion mismatch between device layers
Excessive electrical conductivity
Magnetic interference from the earth
High optical transparency
Explanation - Differential expansion can cause delamination or fracture over long periods.
Correct answer is: Thermal expansion mismatch between device layers
Q.83 In bio‑electronics, the term ‘crosstalk’ refers to:
Unwanted electrical coupling between adjacent channels or electrodes
The magnetic attraction between devices
The diffusion of drugs between compartments
The optical scattering of light
Explanation - Crosstalk degrades signal fidelity and must be minimized through design and shielding.
Correct answer is: Unwanted electrical coupling between adjacent channels or electrodes
Q.84 Which of the following biomaterials is most suitable for a permanent dental implant due to its high strength and biocompatibility?
Zirconia (yttria‑stabilized tetragonal zirconia polycrystal, Y‑TZP)
Polylactic acid (PLA)
Silicone rubber
Polyethylene glycol (PEG)
Explanation - Y‑TZP offers excellent fracture toughness, aesthetics, and biocompatibility for dental applications.
Correct answer is: Zirconia (yttria‑stabilized tetragonal zirconia polycrystal, Y‑TZP)
Q.85 What does the term ‘electrospun nanofiber scaffold’ imply about its fabrication?
It is made by extrusion of molten metal
It is produced by drawing fibers from a polymer solution using a high‑voltage electric field
It is fabricated using laser ablation
It is created by 3D printing of ceramic paste
Explanation - Electrospinning uses electrostatic forces to generate continuous nanofibers that form porous mats.
Correct answer is: It is produced by drawing fibers from a polymer solution using a high‑voltage electric field
Q.86 Which of the following is a major advantage of using ‘wet‑lab’ (in‑vitro) testing before animal studies for biomaterials?
It eliminates the need for any further testing
It provides early insight into cytotoxicity, degradation, and mechanical behavior in a controlled environment
It can replace clinical trials completely
It is faster than any other type of analysis
Explanation - In‑vitro assays allow screening of material safety and performance before more costly animal work.
Correct answer is: It provides early insight into cytotoxicity, degradation, and mechanical behavior in a controlled environment
Q.87 In an implantable glucose sensor, why is a ‘reference electrode’ needed?
To provide a stable baseline potential against which the working electrode’s signal is measured
To emit light for optical detection
To generate magnetic fields for positioning
To dissolve after measurement
Explanation - A reference electrode maintains a constant potential, allowing accurate quantification of glucose oxidation currents.
Correct answer is: To provide a stable baseline potential against which the working electrode’s signal is measured
Q.88 Which of the following factors most directly influences the ‘burst release’ of a drug from a hydrogel matrix?
Hydrogel’s cross‑link density and pore size
Electrical conductivity of the hydrogel
Magnetic permeability of the hydrogel
Optical transparency of the hydrogel
Explanation - Looser networks allow rapid diffusion of drug molecules, causing an initial burst.
Correct answer is: Hydrogel’s cross‑link density and pore size
Q.89 Which material property is essential for a biomaterial used in a hearing aid microphone that must operate in moist ear canals?
High corrosion resistance to saline environments
High magnetic susceptibility
Low optical absorption
High thermal conductivity
Explanation - Moisture and ear secretions can corrode metals; resistant materials ensure longevity and safety.
Correct answer is: High corrosion resistance to saline environments
Q.90 What is the purpose of adding ‘phosphate groups’ to the surface of a polymer used in bone implants?
To make the surface magnetic
To improve osteogenic activity by mimicking natural bone mineral chemistry
To increase the polymer’s melting point
To render the surface hydrophobic
Explanation - Phosphate groups encourage calcium phosphate nucleation, enhancing bone bonding.
Correct answer is: To improve osteogenic activity by mimicking natural bone mineral chemistry
Q.91 Which of the following best describes the function of a ‘dielectric layer’ in a bio‑integrated capacitive sensor?
It stores electrical charge while electrically isolating the conductive plates
It conducts ions to the tissue
It generates heat for therapy
It reflects ultrasound waves
Explanation - Dielectrics allow capacitance formation without allowing DC current flow, essential for capacitive sensing.
Correct answer is: It stores electrical charge while electrically isolating the conductive plates
Q.92 Why is ‘oxygen plasma treatment’ often applied to polymer surfaces before metal deposition?
To increase the surface roughness for better metal adhesion
To make the polymer magnetic
To melt the polymer surface
To reduce the polymer’s dielectric constant
Explanation - Plasma creates polar functional groups and micro‑roughness, improving metal film bonding.
Correct answer is: To increase the surface roughness for better metal adhesion
Q.93 Which of the following materials is most suitable for a bio‑degradable optical fiber used in transient medical imaging?
Polylactic acid (PLA)
Silicon carbide
Gold nanowire
Stainless steel
Explanation - PLA can be drawn into transparent fibers and degrades safely, making it appropriate for temporary optical pathways.
Correct answer is: Polylactic acid (PLA)
Q.94 In the context of bio‑electronic interfaces, what does the term ‘charge storage capacity’ (CSC) refer to?
The total amount of charge that can be stored on the electrode surface during a stimulation pulse
The magnetic field strength of the electrode
The optical absorption of the electrode material
The thermal mass of the electrode
Explanation - CSC determines how much charge can be safely delivered without causing irreversible electrochemical reactions.
Correct answer is: The total amount of charge that can be stored on the electrode surface during a stimulation pulse
Q.95 Which property of a biomaterial is most directly related to its ‘creep’ behavior under constant load?
Viscoelasticity
Electrical conductivity
Magnetic permeability
Optical reflectivity
Explanation - Viscoelastic materials exhibit time‑dependent deformation (creep) under sustained stress.
Correct answer is: Viscoelasticity
Q.96 What is the main function of a ‘passive RFID tag’ made from biocompatible polymer in a medical implant?
To actively transmit data using its own power source
To be read remotely without a battery, providing identification or status information
To generate heat for therapy
To release drugs on demand
Explanation - Passive RFID tags harvest energy from the reader’s electromagnetic field and can store simple data.
Correct answer is: To be read remotely without a battery, providing identification or status information
Q.97 Which of the following is an advantage of using ‘laser‑micromachined’ micro‑channels in a polymeric drug‑delivery patch?
Precise control over channel geometry, enabling tunable drug release rates
Makes the polymer magnetic
Increases the polymer’s electrical conductivity to infinity
Eliminates any need for biocompatibility testing
Explanation - Laser micromachining can create uniform micro‑channels that dictate diffusion pathways and release kinetics.
Correct answer is: Precise control over channel geometry, enabling tunable drug release rates
Q.98 Which of the following statements about ‘bio‑resorbable capacitors’ is correct?
They retain their capacitance indefinitely
They gradually lose capacitance as the dielectric material degrades, providing a temporary power source
They are made of permanent metal plates only
They generate magnetic fields for stimulation
Explanation - As the biodegradable dielectric dissolves, the device’s ability to store charge diminishes, matching transient application needs.
Correct answer is: They gradually lose capacitance as the dielectric material degrades, providing a temporary power source
Q.99 What is the primary purpose of a ‘hydrophobic coating’ on a subcutaneous glucose sensor?
To increase electrical resistance
To reduce protein fouling and prolong sensor accuracy
To make the sensor magnetic
To cause rapid degradation
Explanation - Hydrophobic layers discourage protein adsorption, limiting biofouling and maintaining sensor function.
Correct answer is: To reduce protein fouling and prolong sensor accuracy
Q.100 Which of the following materials exhibits the highest intrinsic electrical conductivity among common biomaterials?
Graphene
Hydrogel
Polylactic acid (PLA)
Silicone rubber
Explanation - Graphene’s two‑dimensional carbon lattice provides exceptional electrical conductivity, far exceeding polymers and hydrogels.
Correct answer is: Graphene
Q.101 In the context of bio‑electronics, why is the ‘water window’ of an electrode material important?
It determines the temperature range in which the electrode works
It defines the voltage range where water electrolysis does not occur, allowing safe stimulation
It sets the optical transmission limit of the material
It controls the magnetic resonance frequency
Explanation - Operating within the water window prevents gas formation that could damage tissue and the electrode.
Correct answer is: It defines the voltage range where water electrolysis does not occur, allowing safe stimulation
Q.102 Which biomaterial is commonly used as a temporary scaffold that degrades after supporting tissue regeneration?
Poly(lactic‑co‑glycolic acid) (PLGA)
Titanium alloy
Silicon carbide
Gold foil
Explanation - PLGA hydrolyzes into lactic and glycolic acids, disappearing after the tissue has healed.
Correct answer is: Poly(lactic‑co‑glycolic acid) (PLGA)
Q.103 Which method is most appropriate for measuring the mechanical modulus of a soft hydrogel intended for brain‑implant applications?
Atomic force microscopy (AFM) indentation
Four‑point bending test
X‑ray diffraction (XRD)
Thermal gravimetric analysis (TGA)
Explanation - AFM can probe nano‑scale mechanical properties of soft, thin hydrogels with high spatial resolution.
Correct answer is: Atomic force microscopy (AFM) indentation
Q.104 Why is ‘low‑frequency impedance spectroscopy’ useful for evaluating the integrity of an implanted bio‑sensor’s encapsulation?
It measures the optical clarity of the encapsulant
It detects changes in the barrier’s dielectric properties that indicate moisture ingress or degradation
It determines the magnetic susceptibility of the sensor
It quantifies the thermal conductivity of the encapsulant
Explanation - Increased impedance at low frequencies can signal water penetration and loss of encapsulation integrity.
Correct answer is: It detects changes in the barrier’s dielectric properties that indicate moisture ingress or degradation
Q.105 Which of the following is a key reason to use ‘biodegradable metals’ such as magnesium for transient implants?
They have infinite mechanical strength
They corrode into biocompatible ions, eliminating the need for surgical removal
They are magnetic and can be externally manipulated
They are completely inert in the body
Explanation - Magnesium degrades into Mg²⁺ ions, which the body can safely process, making it ideal for temporary devices.
Correct answer is: They corrode into biocompatible ions, eliminating the need for surgical removal
Q.106 In a bio‑compatible pressure sensor for intracranial monitoring, the sensing element should have:
High stiffness to avoid deformation
Low Young’s modulus comparable to brain tissue to minimize tissue damage
Magnetic properties for remote activation
High optical reflectivity
Explanation - Matching tissue mechanics reduces inflammatory response and improves sensor performance.
Correct answer is: Low Young’s modulus comparable to brain tissue to minimize tissue damage
Q.107 Which material property primarily governs the ‘ionic conductivity’ of a hydrogel used in bio‑electrodes?
Water content and mobile ion concentration
Electrical resistivity of the polymer backbone
Magnetic permeability of the hydrogel
Thermal expansion coefficient
Explanation - Ionic conduction occurs through dissolved ions in the water phase of the hydrogel.
Correct answer is: Water content and mobile ion concentration
Q.108 What is the purpose of a ‘titanium‑nitride (TiN) nanostructured surface’ on a cochlear implant electrode?
To make the electrode transparent
To increase surface area and lower impedance while providing corrosion resistance
To cause the electrode to dissolve quickly
To generate acoustic waves
Explanation - TiN nanostructures improve charge transfer efficiency and protect the metal underneath.
Correct answer is: To increase surface area and lower impedance while providing corrosion resistance
Q.109 Which of the following is a typical advantage of using ‘nanostructured’ surfaces on biomaterials for cell culture?
They make the surface magnetic
They can mimic the extracellular matrix topography, enhancing cell attachment and differentiation
They prevent any protein adsorption
They increase the material’s weight dramatically
Explanation - Nanotopography influences cell behavior by providing cues similar to natural tissue structures.
Correct answer is: They can mimic the extracellular matrix topography, enhancing cell attachment and differentiation
Q.110 For a bio‑integrated electrode that must function in acidic wound environments, which material is most appropriate?
Silver (Ag)
Stainless steel (304)
Iridium oxide (IrOx)
Copper (Cu)
Explanation - IrOx is chemically stable across a wide pH range and maintains conductivity in harsh environments.
Correct answer is: Iridium oxide (IrOx)
Q.111 Which of the following techniques can be used to create a ‘self‑aligned’ conductive pathway within a polymer for stretchable electronics?
Inkjet printing of silver nanowire ink followed by mechanical stretching
Electroplating of copper onto a rigid substrate
Thermal evaporation of gold onto glass
Sputtering of silicon onto metal
Explanation - Stretching aligns nanowires, forming percolated conductive networks that retain conductivity under deformation.
Correct answer is: Inkjet printing of silver nanowire ink followed by mechanical stretching
Q.112 What is the main advantage of using ‘parylene C’ as an encapsulation layer for implantable electronics?
It is biodegradable within days
It provides a pinhole‑free, conformal, chemically inert barrier that is biocompatible
It makes the device magnetic
It increases the device’s electrical resistance dramatically
Explanation - Parylene C is widely used for its excellent moisture barrier properties and compatibility with medical devices.
Correct answer is: It provides a pinhole‑free, conformal, chemically inert barrier that is biocompatible
Q.113 Which biomaterial property is directly assessed by a ‘tensile test’?
Electrical conductivity
Mechanical strength and elongation at break
Magnetic susceptibility
Optical absorption
Explanation - A tensile test measures how much force a material can withstand before breaking and its ductility.
Correct answer is: Mechanical strength and elongation at break
Q.114 Why is ‘silicone elastomer’ often selected for wearable bio‑sensing patches?
It is highly conductive
It is flexible, biocompatible, and provides good skin adhesion while being moisture resistant
It is magnetic and can be manipulated with external fields
It dissolves quickly in sweat
Explanation - Silicone’s softness and chemical stability make it ideal for long‑term skin contact devices.
Correct answer is: It is flexible, biocompatible, and provides good skin adhesion while being moisture resistant
Q.115 In the design of an implantable bio‑fuel cell, which material property is essential for the anode catalyst?
High catalytic activity for oxidation of bodily fuels (e.g., glucose)
Magnetic permeability
Optical transparency
Low thermal conductivity
Explanation - The anode must efficiently convert biochemical energy into electrons for power generation.
Correct answer is: High catalytic activity for oxidation of bodily fuels (e.g., glucose)
Q.116 Which of the following best explains the term ‘bio‑electrochemical coupling’?
The use of magnetic fields to stimulate cells
The interaction between electrical signals from an implant and the electrochemical environment of tissues
The conversion of light into heat in a polymer
The generation of acoustic waves by a sensor
Explanation - Bio‑electrochemical coupling describes how implanted electrodes exchange charge with ionic body fluids.
Correct answer is: The interaction between electrical signals from an implant and the electrochemical environment of tissues
Q.117 What is the primary reason for using ‘high‑k dielectric materials’ in implantable capacitors?
To increase capacitance without enlarging the device footprint
To make the device magnetic
To improve optical clarity
To reduce mechanical stiffness
Explanation - High dielectric constant materials allow more charge storage per unit area, essential for miniaturized implants.
Correct answer is: To increase capacitance without enlarging the device footprint
Q.118 Which property of a biomaterial determines its ability to resist bacterial colonization?
Antimicrobial surface chemistry (e.g., silver ion release)
Electrical conductivity
Magnetic susceptibility
Optical reflectivity
Explanation - Materials that release antimicrobial agents or have bactericidal surface features inhibit bacterial growth.
Correct answer is: Antimicrobial surface chemistry (e.g., silver ion release)
Q.119 In a flexible bio‑electronic patch, why is ‘strain‑induced resistance change’ (piezoresistivity) important?
It enables the patch to act as a strain sensor, converting mechanical deformation into electrical signals
It makes the patch magnetic
It reduces the patch’s biocompatibility
It causes the patch to dissolve
Explanation - Piezoresistive materials change resistance when stretched, allowing detection of physiological movements.
Correct answer is: It enables the patch to act as a strain sensor, converting mechanical deformation into electrical signals
Q.120 Which of the following is a common method to evaluate the degradation rate of a biodegradable polymer in vitro?
Measuring mass loss over time in a buffered saline solution
Assessing electrical conductivity with a multimeter
Performing X‑ray diffraction analysis
Measuring magnetic susceptibility
Explanation - Mass loss quantifies how quickly the polymer hydrolyzes under physiological conditions.
Correct answer is: Measuring mass loss over time in a buffered saline solution
Q.121 Why is ‘oxygen plasma’ sometimes used before depositing a thin film of PEDOT:PSS on a flexible substrate?
To increase surface energy and improve adhesion of the conductive polymer
To magnetize the substrate
To melt the substrate surface
To change the color of the substrate
Explanation - Plasma treatment introduces polar groups, enhancing wetting and bonding of PEDOT:PSS.
Correct answer is: To increase surface energy and improve adhesion of the conductive polymer
Q.122 Which biomaterial is most suitable for a long‑term sub‑dermal temperature sensor that requires high thermal conductivity?
Diamond‑like carbon (DLC)
Polylactic acid (PLA)
Silicone rubber
Polyethylene glycol (PEG)
Explanation - DLC offers excellent thermal conductivity while being biocompatible and chemically inert.
Correct answer is: Diamond‑like carbon (DLC)
Q.123 What is the role of a ‘reference electrode’ in an amperometric biosensor?
To provide a stable potential against which the working electrode’s current is measured
To emit light for optical detection
To generate magnetic fields for data transmission
To degrade after a set time
Explanation - A constant reference potential allows accurate quantification of the redox reaction current generated by the analyte.
Correct answer is: To provide a stable potential against which the working electrode’s current is measured
Q.124 Which property of a polymer is most affected by ‘photodegradation’ when exposed to UV light?
Mechanical strength and molecular weight
Electrical conductivity
Magnetic permeability
Thermal conductivity
Explanation - UV photons break polymer chains, reducing molecular weight and weakening the material.
Correct answer is: Mechanical strength and molecular weight
Q.125 In the context of bio‑electronic implants, what does the term ‘encapsulation integrity’ refer to?
The ability of the protective coating to prevent fluid ingress and maintain device functionality
The magnetic shielding capability
The optical clarity of the device
The thermal stability of the device
Explanation - Good encapsulation keeps the electronics dry and isolates them from the corrosive body environment.
Correct answer is: The ability of the protective coating to prevent fluid ingress and maintain device functionality
Q.126 Which of the following biomaterials is typically used for a biodegradable stent that gradually loses mechanical support over 6–12 months?
Poly‑L‑lactic acid (PLLA)
Stainless steel
Titanium alloy
Gold
Explanation - PLLA slowly hydrolyzes, providing temporary scaffolding that is resorbed after tissue healing.
Correct answer is: Poly‑L‑lactic acid (PLLA)
Q.127 Why is ‘electrochemical impedance spectroscopy (EIS)’ valuable for monitoring the health of an implanted electrode over time?
It can detect changes in impedance that indicate tissue encapsulation or corrosion
It measures the magnetic field around the electrode
It determines the optical absorption of surrounding tissue
It records the temperature of the electrode
Explanation - Increasing impedance often signals fouling or material degradation, informing device maintenance decisions.
Correct answer is: It can detect changes in impedance that indicate tissue encapsulation or corrosion
Q.128 Which material is commonly used as a transparent, flexible electrode in wearable ECG patches?
Indium tin oxide (ITO) on a PET substrate
Copper wire
Aluminum foil
Gold bulk plate
Explanation - ITO provides good conductivity while being optically transparent and flexible on PET.
Correct answer is: Indium tin oxide (ITO) on a PET substrate
Q.129 In a biodegradable neural interface, why might magnesium be alloyed with zinc?
To increase the corrosion rate dramatically
To fine‑tune mechanical properties and slow down degradation for longer functional life
To make the alloy magnetic
To render the alloy fluorescent
Explanation - Alloying adjusts strength, ductility, and corrosion kinetics, extending the device’s usable period.
Correct answer is: To fine‑tune mechanical properties and slow down degradation for longer functional life
Q.130 Which of the following describes the main advantage of ‘microfluidic channels’ integrated into a drug‑delivery patch?
They enable precise, programmable dosing by controlling fluid flow paths
They generate magnetic fields for stimulation
They increase the patch’s optical reflectivity
They make the patch biodegradable in minutes
Explanation - Microfluidics allow accurate dosing schedules, reducing variability in drug administration.
Correct answer is: They enable precise, programmable dosing by controlling fluid flow paths
Q.131 What is the primary reason for using ‘silane coupling agents’ when bonding glass to a polymer in a biosensor?
To create covalent bonds between inorganic and organic surfaces, improving adhesion
To make the assembly magnetic
To increase the optical transparency of the polymer
To cause rapid degradation of the glass
Explanation - Silane molecules have functional groups that react with both glass (siloxane) and polymer (hydroxyl), forming strong interfaces.
Correct answer is: To create covalent bonds between inorganic and organic surfaces, improving adhesion
Q.132 Which property of a biomaterial determines its ‘hydrophilicity’?
Water contact angle – lower angles indicate higher hydrophilicity
Electrical resistance
Magnetic permeability
Thermal conductivity
Explanation - A water contact angle < 90° signifies a surface that readily wets, indicating hydrophilic behavior.
Correct answer is: Water contact angle – lower angles indicate higher hydrophilicity
Q.133 In a bio‑electronic system, why is ‘low‑frequency noise’ a concern for neural recording electrodes?
It can mask the small amplitude neural signals, reducing recording fidelity
It increases the device’s magnetic field
It improves the electrode’s biocompatibility
It enhances drug release
Explanation - Neural spikes are low‑amplitude; low‑frequency noise can drown them out, compromising data quality.
Correct answer is: It can mask the small amplitude neural signals, reducing recording fidelity
Q.134 Which of the following is a benefit of using ‘3‑D printing’ to fabricate patient‑specific biomaterial implants?
Ability to create complex geometries that match patient anatomy, reducing surgical time
It makes the implant magnetic
It automatically sterilizes the implant
It eliminates the need for any material testing
Explanation - Additive manufacturing allows customization of shape and internal architecture for optimal fit and function.
Correct answer is: Ability to create complex geometries that match patient anatomy, reducing surgical time
Q.135 What is the primary function of a ‘bio‑inert’ coating such as titanium oxide on a metallic implant?
To actively promote bone growth
To provide a stable, non‑reactive surface that minimizes immune response
To make the implant magnetic
To cause rapid dissolution
Explanation - Bio‑inert surfaces do not interact chemically with tissues, reducing inflammation and fibrosis.
Correct answer is: To provide a stable, non‑reactive surface that minimizes immune response
Q.136 Which material characteristic is most critical for an implantable antenna used for wireless power transfer?
High dielectric constant and low loss tangent at the operating frequency
Magnetic susceptibility
Optical transparency
Thermal expansion coefficient
Explanation - These properties enable efficient electromagnetic coupling and minimal energy loss in tissue.
Correct answer is: High dielectric constant and low loss tangent at the operating frequency
Q.137 In a bio‑electronic interface, what does ‘faradaic efficiency’ measure?
The fraction of charge that results in the desired electrochemical reaction versus side reactions
The magnetic field strength produced
The optical clarity of the electrode
The thermal resistance of the device
Explanation - High faradaic efficiency indicates that most of the supplied charge drives the intended redox process.
Correct answer is: The fraction of charge that results in the desired electrochemical reaction versus side reactions
Q.138 Which of the following is a reason to use ‘conductive hydrogel’ as an interface layer between a metal electrode and neural tissue?
It reduces mechanical mismatch and provides ionic conductivity similar to tissue
It makes the electrode magnetic
It completely blocks all electrical signals
It causes rapid tissue degradation
Explanation - Hydrogels are soft and conductive, matching tissue mechanics and improving charge transfer.
Correct answer is: It reduces mechanical mismatch and provides ionic conductivity similar to tissue
Q.139 Which of the following techniques is most appropriate for measuring the surface chemical composition of a biomaterial coating?
X‑ray photoelectron spectroscopy (XPS)
Scanning electron microscopy (SEM)
Thermogravimetric analysis (TGA)
Dynamic mechanical analysis (DMA)
Explanation - XPS provides quantitative elemental and chemical state information from the top few nanometers of a surface.
Correct answer is: X‑ray photoelectron spectroscopy (XPS)
Q.140 What is a primary concern when using ‘metallic nanowires’ as transparent conductors in ocular implants?
Potential cytotoxicity and leaching of metal ions
Excessive magnetic field generation
Complete opacity to visible light
High thermal conductivity leading to overheating
Explanation - Metal ions can be toxic; careful encapsulation or selection of biocompatible metals is required.
Correct answer is: Potential cytotoxicity and leaching of metal ions
Q.141 Which property of a polymer dictates its ability to act as a ‘diffusion barrier’ for moisture in implantable devices?
Low water vapor transmission rate (WVTR)
High electrical conductivity
Magnetic susceptibility
Optical reflectivity
Explanation - A low WVTR indicates the polymer resists moisture permeation, protecting internal electronics.
Correct answer is: Low water vapor transmission rate (WVTR)
Q.142 Why is ‘poly(ethylene glycol) (PEG)’ frequently used to modify the surface of biomaterials?
It creates a hydrophilic, protein‑resistant layer that reduces biofouling
It makes the surface magnetic
It increases the material’s electrical conductivity
It causes rapid degradation in the body
Explanation - PEG chains form a hydrated brush that repels proteins and cells, improving biocompatibility.
Correct answer is: It creates a hydrophilic, protein‑resistant layer that reduces biofouling