Q.1 What does the term “composite biomaterial” refer to?
A material made from a single pure element
A combination of two or more distinct materials designed for biological use
A metal alloy used only in construction
A polymer that cannot conduct electricity
Explanation - Composite biomaterials are engineered by combining two or more constituent materials (e.g., polymers, ceramics, metals) to achieve properties that are beneficial for biomedical applications.
Correct answer is: A combination of two or more distinct materials designed for biological use
Q.2 Which component in a conductive polymer composite provides electrical conductivity?
Silica filler
Carbon nanotubes
Hydroxyapatite particles
Calcium phosphate
Explanation - Carbon nanotubes have excellent electrical conductivity and are often added to polymer matrices to create conductive composites for bioelectronic devices.
Correct answer is: Carbon nanotubes
Q.3 Polypyrrole (PPy) is commonly used in composite biomaterials because it:
Is highly biodegradable
Has excellent electrical conductivity
Is magnetic
Has a high melting point
Explanation - Polypyrrole is a conductive polymer, making it suitable for interfacing electronics with biological tissues.
Correct answer is: Has excellent electrical conductivity
Q.4 In a neural electrode, why is a composite material preferred over a single metal?
Composite materials are cheaper
They can combine flexibility with conductivity, reducing tissue damage
They are always biodegradable
They prevent any electrical signal transmission
Explanation - A composite can be engineered to be flexible (reducing mechanical mismatch with tissue) while maintaining necessary electrical properties.
Correct answer is: They can combine flexibility with conductivity, reducing tissue damage
Q.5 Which of the following is a typical insulating component in a conductive composite biomaterial?
Gold nanoparticles
Silicone elastomer
Graphene sheets
Silver nanowires
Explanation - Silicone elastomer provides a flexible, insulating matrix that can host conductive fillers like silver nanowires.
Correct answer is: Silicone elastomer
Q.6 Hydroxyapatite is added to polymer composites primarily to:
Increase electrical conductivity
Improve mechanical strength and bioactivity for bone tissue
Make the material magnetic
Reduce the cost of the composite
Explanation - Hydroxyapatite mimics the mineral component of bone, enhancing osteointegration and mechanical properties of composites.
Correct answer is: Improve mechanical strength and bioactivity for bone tissue
Q.7 What is the main advantage of using a graphene‑based composite in bioelectronic sensors?
Graphene is opaque to light
Graphene provides high surface area and exceptional conductivity
Graphene makes the sensor biodegradable within a day
Graphene reduces the sensor’s weight to zero
Explanation - Graphene’s large surface area and high electrical conductivity enhance signal transduction in bioelectronic sensors.
Correct answer is: Graphene provides high surface area and exceptional conductivity
Q.8 Which property is most critical for a composite biomaterial used in a cardiac pacing lead?
Thermal insulation
Electrical conductivity and flexibility
Magnetic permeability
Optical transparency
Explanation - A pacing lead must conduct electrical impulses while conforming to the heart’s movement, requiring both conductivity and flexibility.
Correct answer is: Electrical conductivity and flexibility
Q.9 In a composite used for neural interfaces, the term “percolation threshold” refers to:
The temperature at which the composite melts
The minimum filler concentration needed for a continuous conductive path
The point at which the composite becomes biodegradable
The maximum voltage the composite can handle
Explanation - The percolation threshold is the filler loading at which conductive particles form a continuous network, enabling electrical conductivity.
Correct answer is: The minimum filler concentration needed for a continuous conductive path
Q.10 Which of the following is a common method to fabricate polymer‑ceramic composites for bone scaffolds?
Electrospinning
Thermal spraying
Chemical vapor deposition
Laser cutting
Explanation - Electrospinning can create nanofibrous scaffolds that incorporate ceramic particles like hydroxyapatite for bone tissue engineering.
Correct answer is: Electrospinning
Q.11 Why are biodegradable composites desirable for temporary neural probes?
They permanently stay in the brain
They eliminate the need for surgical removal after function is fulfilled
They increase electrical resistance over time
They make the probe magnetic
Explanation - Biodegradable composites safely dissolve after their functional period, reducing the need for a second surgery.
Correct answer is: They eliminate the need for surgical removal after function is fulfilled
Q.12 Which of the following fillers would most likely increase the stiffness of a polymer composite without improving conductivity?
Carbon black
Silica nanoparticles
Gold nanorods
Polyaniline
Explanation - Silica nanoparticles reinforce the polymer matrix, increasing stiffness, but they are not conductive.
Correct answer is: Silica nanoparticles
Q.13 In the context of bio‑electronic composites, “impedance matching” is important because:
It reduces the mechanical strength of the device
It maximizes signal transfer between the device and tissue
It makes the device waterproof
It changes the color of the composite
Explanation - Matching the electrical impedance of the electrode to that of the surrounding tissue improves signal quality and reduces noise.
Correct answer is: It maximizes signal transfer between the device and tissue
Q.14 What is the role of a “crosslinker” in a polymer‑based composite biomaterial?
To increase the composite’s electrical resistance
To bond polymer chains, enhancing mechanical stability
To make the composite magnetic
To dissolve the composite in water
Explanation - Crosslinkers create covalent bonds between polymer chains, improving structural integrity and sometimes influencing conductivity.
Correct answer is: To bond polymer chains, enhancing mechanical stability
Q.15 Which of the following composite structures is most suitable for a flexible wearable biosensor?
Rigid ceramic‑metal alloy
Silicone matrix with silver nanowires
Dense glass fiber composite
Pure copper sheet
Explanation - A silicone elastomer provides flexibility while silver nanowires impart conductivity, ideal for wearables.
Correct answer is: Silicone matrix with silver nanowires
Q.16 The term “bio‑compatibility” for a composite biomaterial means:
The material can conduct electricity better than copper
The material does not cause an adverse reaction when implanted
The material can be magnetized
The material dissolves instantly in blood
Explanation - Biocompatibility indicates that the material is non‑toxic, non‑immunogenic, and integrates well with biological tissue.
Correct answer is: The material does not cause an adverse reaction when implanted
Q.17 Which measurement technique is commonly used to assess the electrical conductivity of a composite biomaterial?
Scanning electron microscopy (SEM)
Four‑point probe method
X‑ray diffraction (XRD)
Thermogravimetric analysis (TGA)
Explanation - The four‑point probe minimizes contact resistance, providing accurate conductivity measurements for thin films and composites.
Correct answer is: Four‑point probe method
Q.18 A composite biomaterial intended for muscle stimulation must possess which combination of properties?
High optical opacity and low stiffness
Electrical conductivity, flexibility, and biocompatibility
Magnetic susceptibility and high density
Thermal insulation and brittleness
Explanation - Muscle stimulators require conductive pathways, must conform to muscle movement, and must not provoke immune response.
Correct answer is: Electrical conductivity, flexibility, and biocompatibility
Q.19 In a polymer‑metal composite used for a bio‑electrode, the metal phase primarily contributes:
Mechanical softness
Electrical conductivity
Biodegradability
Optical clarity
Explanation - Metallic fillers such as gold or silver provide high conductivity, while the polymer matrix offers flexibility and biocompatibility.
Correct answer is: Electrical conductivity
Q.20 Which of the following is a major challenge when integrating conductive fillers into a polymer matrix?
Achieving uniform dispersion without agglomeration
Increasing the polymer’s melting point above 500 °C
Making the composite magnetic
Removing all water from the composite
Explanation - Agglomerated fillers can create weak spots and non‑uniform conductivity, reducing device performance.
Correct answer is: Achieving uniform dispersion without agglomeration
Q.21 What is the typical purpose of adding a “bio‑active” ceramic like bio‑glass to a conductive polymer composite?
To increase electrical resistance
To promote cell attachment and tissue integration
To make the composite transparent
To lower the composite’s cost dramatically
Explanation - Bio‑active ceramics release ions that stimulate cellular responses, enhancing integration of the implant.
Correct answer is: To promote cell attachment and tissue integration
Q.22 Which composite design would best reduce the risk of foreign‑body response for an implanted sensor?
A stiff titanium alloy
A soft hydrogel with embedded gold nanowires
A brittle ceramic rod
A dense lead sheet
Explanation - Soft hydrogels match the mechanical properties of soft tissue, decreasing irritation, while gold nanowires provide conductivity.
Correct answer is: A soft hydrogel with embedded gold nanowires
Q.23 In the context of composite biomaterials, “anisotropy” means:
The material has the same properties in all directions
The material’s properties vary with direction
The material dissolves in water
The material is magnetic
Explanation - Anisotropic composites exhibit direction‑dependent mechanical or electrical behavior, which can be engineered for specific functions.
Correct answer is: The material’s properties vary with direction
Q.24 Which technique can align carbon nanotubes inside a polymer to improve directional conductivity?
Melt blending
Magnetic field assisted alignment
Ultrasonic cleaning
Freeze‑drying
Explanation - Applying a magnetic field can orient magnetic‑coated carbon nanotubes, creating pathways for enhanced conductivity along a preferred direction.
Correct answer is: Magnetic field assisted alignment
Q.25 The degradation rate of a biodegradable composite biomaterial is primarily controlled by:
The color of the material
The type and amount of biodegradable polymer matrix
The magnetic field applied during fabrication
The electrical voltage used during testing
Explanation - Biodegradable polymers such as PLGA dictate how quickly the composite breaks down in vivo.
Correct answer is: The type and amount of biodegradable polymer matrix
Q.26 Which of the following is NOT a typical requirement for a composite used in an implantable cardiac electrode?
Long‑term corrosion resistance
High thermal conductivity
Flexibility to accommodate heart motion
Biocompatibility
Explanation - Thermal conductivity is less critical than mechanical flexibility, corrosion resistance, and biocompatibility for cardiac electrodes.
Correct answer is: High thermal conductivity
Q.27 Electrochemical impedance spectroscopy (EIS) is used in testing composite biomaterials to:
Measure their magnetic susceptibility
Determine their optical reflectivity
Evaluate their electrical interface properties with tissue
Calculate their density
Explanation - EIS provides frequency‑dependent impedance data, which helps assess the quality of bio‑electronic interfaces.
Correct answer is: Evaluate their electrical interface properties with tissue
Q.28 A composite containing polylactic acid (PLA) and graphene is likely to have:
Reduced mechanical strength compared to pure PLA
Improved electrical conductivity while maintaining biodegradability
Magnetic properties suitable for MRI
Zero water absorption
Explanation - Graphene adds conductivity, and PLA remains biodegradable, giving a conductive biodegradable composite.
Correct answer is: Improved electrical conductivity while maintaining biodegradability
Q.29 Why is the Young’s modulus of a composite biomaterial important for neural interfaces?
It determines the composite’s color
A modulus close to brain tissue reduces mechanical mismatch and inflammation
It controls the magnetic field of the device
It sets the voltage limit of the device
Explanation - Matching mechanical stiffness minimizes chronic tissue response and improves long‑term functionality of neural implants.
Correct answer is: A modulus close to brain tissue reduces mechanical mismatch and inflammation
Q.30 Which processing method allows simultaneous polymer curing and filler alignment for anisotropic composites?
Hot pressing
Shear‑induced extrusion
Solvent evaporation
Laser ablation
Explanation - During extrusion, shear forces can align high‑aspect‑ratio fillers while the polymer cures, creating anisotropic conductive pathways.
Correct answer is: Shear‑induced extrusion
Q.31 In a bio‑electronic composite, the term “self‑healing” refers to:
The ability of the material to repair micro‑cracks autonomously
The capacity to change color when stressed
The composite’s resistance to electrical current
The material’s ability to conduct heat
Explanation - Self‑healing polymers can reform bonds after damage, extending the lifetime of implanted devices.
Correct answer is: The ability of the material to repair micro‑cracks autonomously
Q.32 Which of the following is a benefit of using a “piezoelectric” composite in a biomedical sensor?
It can convert mechanical strain into electrical signals
It makes the sensor invisible
It increases the sensor’s weight dramatically
It prevents any electrical activity
Explanation - Piezoelectric composites generate voltage when deformed, enabling mechanical‑to‑electrical transduction in implants.
Correct answer is: It can convert mechanical strain into electrical signals
Q.33 For a composite biomaterial used in cochlear implants, the most critical electrical property is:
Low resistivity to transmit high‑frequency signals
High magnetic permeability
High thermal conductivity
Low optical reflectivity
Explanation - Cochlear implants require efficient high‑frequency signal transmission to stimulate auditory nerves.
Correct answer is: Low resistivity to transmit high‑frequency signals
Q.34 Which additive can improve both conductivity and antimicrobial activity in a polymer composite?
Silver nanoparticles
Silicon dioxide
Calcium carbonate
Polyethylene glycol
Explanation - Silver nanoparticles are conductive and possess well‑known antimicrobial properties, making them useful for implantable devices.
Correct answer is: Silver nanoparticles
Q.35 In designing a composite for a flexible retinal prosthesis, which characteristic is least important?
Transparency
Mechanical flexibility
Electrical conductivity
High density
Explanation - A lightweight, flexible, and transparent material is essential; high density would add unnecessary weight.
Correct answer is: High density
Q.36 A composite biomaterial with a “gradient” structure means:
Its composition changes gradually across its volume
It is made of a single uniform material
It can only be used in gradient‑based calculations
It has a constant magnetic field
Explanation - Gradient composites can tailor mechanical and electrical properties spatially, useful for tissue interfaces with varying stiffness.
Correct answer is: Its composition changes gradually across its volume
Q.37 Which measurement would you use to evaluate the mechanical strength of a composite scaffold?
Four‑point bending test
Spectrophotometry
Electrochemical impedance spectroscopy
Thermal gravimetric analysis
Explanation - Four‑point bending provides data on flexural strength and stiffness, key for scaffold mechanical performance.
Correct answer is: Four‑point bending test
Q.38 In a conductive hydrogel composite, the hydrogel provides:
Electrical conductivity
Mechanical rigidity
A water‑rich, biocompatible matrix
Magnetic properties
Explanation - Hydrogels mimic soft tissue environments, while conductive fillers inside provide the electrical pathways.
Correct answer is: A water‑rich, biocompatible matrix
Q.39 What is the main reason for using a “dual‑phase” composite (conductive + bio‑active) in bone‑electrode applications?
To make the device heavier
To provide both electrical stimulation and promote bone growth
To increase the device’s temperature
To create magnetic fields inside bone
Explanation - Combining conductive and bio‑active phases enables simultaneous electrical therapy and osteointegration.
Correct answer is: To provide both electrical stimulation and promote bone growth
Q.40 Which of the following is a commonly used biodegradable polymer for electrical composites?
Polyethylene terephthalate (PET)
Polylactic acid (PLA)
Polystyrene (PS)
Polyvinyl chloride (PVC)
Explanation - PLA is biodegradable, biocompatible, and can be blended with conductive fillers for transient electronics.
Correct answer is: Polylactic acid (PLA)
Q.41 In a composite electrode, why might a thin layer of titanium nitride (TiN) be added?
To increase the electrode’s opacity
To improve charge‑injection capacity and biostability
To make the electrode magnetic
To reduce the electrode’s mechanical strength
Explanation - TiN provides a high surface area, low impedance, and stable interface for long‑term stimulation.
Correct answer is: To improve charge‑injection capacity and biostability
Q.42 Which fabrication technique can create 3‑D printed composite scaffolds with embedded conductive pathways?
Fused deposition modeling (FDM) with conductive filament
Laser cutting of metal sheets
Electroplating of polymer surfaces
Molding with pure silicone
Explanation - FDM can print polymeric composites that include conductive filaments, allowing designed conductive networks in 3‑D structures.
Correct answer is: Fused deposition modeling (FDM) with conductive filament
Q.43 What does “bio‑resorbable” mean for a composite material used in a temporary neural interface?
It conducts electricity forever
It can be dissolved and cleared by the body over time
It becomes magnetic after implantation
It turns into bone tissue
Explanation - Bio‑resorbable composites safely degrade and are eliminated, removing the need for surgical extraction.
Correct answer is: It can be dissolved and cleared by the body over time
Q.44 When designing a composite for an implantable glucose sensor, which property is most critical?
High optical transparency
Selective permeability to glucose while blocking interfering species
Magnetic susceptibility
Very high hardness
Explanation - A selective barrier ensures accurate glucose detection without fouling or interference from other molecules.
Correct answer is: Selective permeability to glucose while blocking interfering species
Q.45 Which of the following can be used to impart self‑powered functionality to a composite biomaterial?
Incorporating piezoelectric nanowires that generate voltage from body motion
Adding extra weight to the composite
Coating the composite with reflective paint
Embedding a battery that cannot be recharged
Explanation - Piezoelectric nanowires can harvest mechanical energy from movement, providing a self‑sustaining power source.
Correct answer is: Incorporating piezoelectric nanowires that generate voltage from body motion
Q.46 In a composite biomaterial used for peripheral nerve regeneration, the conductive filler is primarily needed to:
Increase the composite’s color contrast
Provide electrical cues that promote neurite outgrowth
Make the material magnetic
Raise the melting temperature of the polymer
Explanation - Electrical stimulation enhances nerve regeneration; conductive fillers create the required pathways.
Correct answer is: Provide electrical cues that promote neurite outgrowth
Q.47 What is the main reason to use a “core‑shell” structured filler in a polymer composite?
To reduce the composite’s weight
To combine a conductive core with a biocompatible shell, improving dispersion and reducing toxicity
To make the filler magnetic
To increase the polymer’s melting point
Explanation - Core‑shell designs protect the conductive core, enhance compatibility, and prevent agglomeration.
Correct answer is: To combine a conductive core with a biocompatible shell, improving dispersion and reducing toxicity
Q.48 Which analytical technique would best verify the uniform distribution of graphene within a polymer matrix?
Raman spectroscopy mapping
Differential scanning calorimetry (DSC)
Thermal conductivity measurement
Viscosity testing
Explanation - Raman mapping can spatially resolve graphene’s characteristic peaks, showing dispersion quality.
Correct answer is: Raman spectroscopy mapping
Q.49 A composite biomaterial designed for an implantable ECG electrode must have a surface that:
Be highly reflective
Promote stable electrical contact with heart tissue over long periods
Absorb water quickly
Be electrically insulating
Explanation - Stable low‑impedance contact ensures reliable ECG signal acquisition.
Correct answer is: Promote stable electrical contact with heart tissue over long periods
Q.50 Which property of a polymer matrix most influences the diffusion rate of ions through a conductive composite?
Glass transition temperature (Tg)
Optical index of refraction
Magnetic susceptibility
Melting point
Explanation - A lower Tg usually means higher chain mobility, which can increase ion diffusion through the polymer.
Correct answer is: Glass transition temperature (Tg)
Q.51 The term “electro‑spinning” is mainly used to produce:
Thin polymer fibers with incorporated conductive fillers for flexible bio‑electronics
Metallic rods for structural support
Bulk ceramic blocks
Magnetic nanoparticles
Explanation - Electro‑spinning creates nanofibrous mats that can embed conductive particles, useful for wearable and implantable sensors.
Correct answer is: Thin polymer fibers with incorporated conductive fillers for flexible bio‑electronics
Q.52 Which of the following statements about “self‑assembled” conductive composites is true?
They require high‑temperature sintering to function
They rely on spontaneous organization of nanofillers into conductive networks without external forces
They are always magnetic
They cannot be biocompatible
Explanation - Self‑assembly leverages intermolecular forces to arrange conductive fillers, simplifying fabrication.
Correct answer is: They rely on spontaneous organization of nanofillers into conductive networks without external forces
Q.53 A composite biomaterial intended for a spinal cord stimulator should have a Young’s modulus close to:
10 GPa (similar to steel)
0.1–1 MPa (similar to soft tissue)
100 GPa (similar to diamond)
5 GPa (similar to bone)
Explanation - Matching the low stiffness of spinal cord tissue reduces mechanical irritation and improves integration.
Correct answer is: 0.1–1 MPa (similar to soft tissue)
Q.54 Which composite architecture enables simultaneous drug release and electrical stimulation?
Layered structure with a drug‑laden hydrogel over a conductive polymer layer
Solid metal rod
Pure ceramic block
Rigid glass fiber composite
Explanation - The layered design separates the drug reservoir from the conductive layer while allowing both functions.
Correct answer is: Layered structure with a drug‑laden hydrogel over a conductive polymer layer
Q.55 In the context of composite biomaterials, “ionic conductivity” is important for:
Generating magnetic fields
Facilitating ion transport in bio‑electronic interfaces such as neural probes
Increasing optical transparency
Reducing material density
Explanation - Ionic conductivity enables efficient charge transfer between the device and biological ions.
Correct answer is: Facilitating ion transport in bio‑electronic interfaces such as neural probes
Q.56 What is the purpose of adding a “plasticizer” to a polymer composite used for flexible implants?
To increase the composite’s brittleness
To lower the glass transition temperature, making the material more flexible
To make the material magnetic
To raise the composite’s density
Explanation - Plasticizers increase chain mobility, reducing stiffness and enhancing flexibility for soft‑tissue applications.
Correct answer is: To lower the glass transition temperature, making the material more flexible
Q.57 Which of the following is an example of a “bio‑electronic” composite material?
Silicone rubber with embedded silver nanowires for a stretchable skin electrode
Aluminium alloy used for aircraft wings
Pure glass fiber board
Steel reinforcement bars
Explanation - This composite combines a soft matrix with conductive fillers, ideal for interfacing electronics with biological tissue.
Correct answer is: Silicone rubber with embedded silver nanowires for a stretchable skin electrode
Q.58 A composite with a high “aspect ratio” filler (e.g., nanofibers) typically shows:
Higher percolation threshold compared to spherical particles
Lower percolation threshold, meaning less filler needed for conductivity
No change in electrical properties
Increased magnetic susceptibility
Explanation - High‑aspect‑ratio fillers form conductive networks more efficiently, reducing the amount required.
Correct answer is: Lower percolation threshold, meaning less filler needed for conductivity
Q.59 Which factor most influences the long‑term stability of an implantable composite electrode?
The color of the polymer
Corrosion resistance of the conductive filler and encapsulation integrity
The presence of fluorescent dyes
The acoustic properties of the material
Explanation - Resistance to corrosion prevents failure and maintains electrical performance over years.
Correct answer is: Corrosion resistance of the conductive filler and encapsulation integrity
Q.60 Which of the following statements best describes “electro‑active polymers (EAPs)” in composite biomaterials?
Polymers that change shape or conduct electricity when stimulated by an electric field
Polymers that are magnetic
Polymers that are completely inert
Polymers that melt at low temperature
Explanation - EAPs can serve as actuators or sensors in bio‑electronics due to their electric field‑responsive behavior.
Correct answer is: Polymers that change shape or conduct electricity when stimulated by an electric field
Q.61 The inclusion of “bio‑glass” particles in a conductive polymer composite primarily serves to:
Increase the composite’s magnetic field
Improve bioactivity and promote cell adhesion while maintaining conductivity
Make the composite opaque
Reduce the composite’s electrical resistance to zero
Explanation - Bio‑glass releases ions that stimulate tissue growth, complementing the conductive polymer’s electrical function.
Correct answer is: Improve bioactivity and promote cell adhesion while maintaining conductivity
Q.62 A composite electrode used for deep brain stimulation must minimize which of the following to avoid tissue damage?
Charge density per phase
Mechanical flexibility
Electrical conductivity
Biocompatibility
Explanation - Excessive charge density can cause electrochemical damage; composite design aims to lower impedance to keep charge density low.
Correct answer is: Charge density per phase
Q.63 Which of the following best explains why “nanocomposites” are advantageous for bio‑electronic applications?
Nanoparticles increase the weight dramatically
Nanoparticles provide a large surface‑to‑volume ratio, enhancing conductivity and interaction with cells
Nanoparticles make the material magnetic
Nanoparticles block all electrical signals
Explanation - Higher surface area improves electron transport and biological interfacing.
Correct answer is: Nanoparticles provide a large surface‑to‑volume ratio, enhancing conductivity and interaction with cells
Q.64 When a composite biomaterial is described as “electrochemically stable,” it means:
It does not change its color over time
It maintains its electrical properties without degradation during repeated stimulation cycles
It becomes magnetic after exposure to water
It dissolves instantly in body fluids
Explanation - Electrochemical stability ensures long‑term performance of implanted electrodes.
Correct answer is: It maintains its electrical properties without degradation during repeated stimulation cycles
Q.65 A conductive composite used for a retinal prosthesis must possess which optical property?
High opacity to block light
High transparency to allow light passage while delivering electrical stimulation
Strong fluorescence
Magnetic reflectivity
Explanation - The prosthesis must let light reach the photoreceptors while providing electrical cues.
Correct answer is: High transparency to allow light passage while delivering electrical stimulation
Q.66 Which of the following is a potential drawback of using high loading of metallic nanoparticles in a polymer composite?
Increased flexibility
Potential cytotoxicity and reduced polymer processability
Enhanced optical clarity
Reduced electrical conductivity
Explanation - Excess metal particles can be toxic to cells and make the polymer difficult to melt or extrude.
Correct answer is: Potential cytotoxicity and reduced polymer processability
Q.67 In the context of composite biomaterials, “interfacial adhesion” refers to:
The magnetic attraction between filler and matrix
The strength of bonding between filler particles and the polymer matrix, influencing mechanical and electrical performance
The optical bonding between layers
The ability of the composite to float on water
Explanation - Good interfacial adhesion ensures stress transfer and maintains conductive pathways.
Correct answer is: The strength of bonding between filler particles and the polymer matrix, influencing mechanical and electrical performance
Q.68 Which testing method would you use to assess the long‑term electrochemical degradation of a composite electrode in simulated body fluid?
Accelerated aging with cyclic voltammetry
X‑ray diffraction
Thermal conductivity measurement
Optical microscopy
Explanation - Cyclic voltammetry under accelerated conditions reveals corrosion and degradation behaviors over time.
Correct answer is: Accelerated aging with cyclic voltammetry
Q.69 A composite material for a stretchable cardiac patch must maintain conductivity under:
Static conditions only
Large cyclic strains matching heart motion
High temperature above 200 °C
Vacuum environments
Explanation - The patch experiences repetitive stretching; the conductive network must stay intact during deformation.
Correct answer is: Large cyclic strains matching heart motion
Q.70 Which of the following nanofillers is most commonly used to create a “transparent conductive” composite for retinal implants?
Silver nanowires
Carbon black
Gold nanoparticles
Aluminum powder
Explanation - Silver nanowires form percolating networks that are both highly conductive and transparent when sparsely distributed.
Correct answer is: Silver nanowires
Q.71 In a composite biomaterial used for deep tissue stimulation, the presence of a “hydrophilic” polymer matrix helps:
Increase the material’s magnetic properties
Facilitate ionic transport and reduce impedance at the tissue interface
Make the material opaque
Raise the composite’s melting point
Explanation - Hydrophilic matrices allow body fluids to permeate, improving ionic conduction and lowering interfacial impedance.
Correct answer is: Facilitate ionic transport and reduce impedance at the tissue interface
Q.72 Which property is most critical for a composite used in an implantable hearing aid microphone?
High thermal conductivity
Acoustic transparency and low mass
Magnetic susceptibility
High hardness
Explanation - The device must transmit sound efficiently without adding weight or dampening vibrations.
Correct answer is: Acoustic transparency and low mass
Q.73 A composite with a “multilayered” architecture can be designed to:
Provide separate layers for mechanical protection, electrical conduction, and drug release
Increase the overall weight dramatically
Make the composite magnetic
Eliminate all electrical conductivity
Explanation - Layered designs enable multifunctionality, each layer optimized for a specific role.
Correct answer is: Provide separate layers for mechanical protection, electrical conduction, and drug release
Q.74 When evaluating the biocompatibility of a new composite biomaterial, which assay is commonly performed?
MTT or live‑dead cell viability assay
Four‑point probe conductivity test
X‑ray diffraction analysis
Thermal gravimetric analysis
Explanation - Cell viability assays assess cytotoxicity, a key aspect of biocompatibility.
Correct answer is: MTT or live‑dead cell viability assay
Q.75 Which factor most directly influences the “charge storage capacity” of a conductive composite electrode?
Surface area and effective capacitance of the conductive filler
The color of the polymer matrix
The magnetic permeability of the composite
The optical clarity of the filler
Explanation - Higher surface area (e.g., from nanostructured fillers) increases charge storage, enhancing stimulation efficiency.
Correct answer is: Surface area and effective capacitance of the conductive filler
Q.76 Which composite material would be most suitable for a biodegradable, electrically conductive scaffold for peripheral nerve repair?
Polylactic acid (PLA) blended with carbon nanotubes
Pure stainless steel mesh
Rigid glass fiber composite
Aluminium foil
Explanation - PLA is biodegradable, and carbon nanotubes provide conductivity, creating a transient, conductive scaffold.
Correct answer is: Polylactic acid (PLA) blended with carbon nanotubes