Q.1 Which property of a biomaterial is most critical for minimizing electrical impedance when used as an electrode in neural tissue engineering?
Young's modulus
Electrical conductivity
Thermal conductivity
Poisson's ratio
Explanation - Low electrical impedance requires a material with high electrical conductivity, allowing efficient charge transfer between the electrode and neural tissue.
Correct answer is: Electrical conductivity
Q.2 In tissue engineering scaffolds, what is the primary purpose of incorporating conductive polymers like polypyrrole?
To increase scaffold stiffness
To promote cell adhesion
To enable electrical stimulation of cells
To enhance biodegradability
Explanation - Conductive polymers allow the scaffold to deliver electrical cues that can direct cell differentiation and function, especially in muscle and nerve tissue engineering.
Correct answer is: To enable electrical stimulation of cells
Q.3 Which of the following is a commonly used technique to fabricate 3‑D porous conductive scaffolds for cardiac tissue engineering?
Electrospinning of gold nanowires
3‑D printing with graphene‑infused inks
Sol‑gel processing of silica
Melt extrusion of polypropylene
Explanation - Graphene‑infused inks can be extruded in a layer‑by‑layer fashion to create conductive, porous structures suitable for cardiac patches.
Correct answer is: 3‑D printing with graphene‑infused inks
Q.4 What is the main advantage of using piezoelectric materials such as barium titanate in bone tissue engineering scaffolds?
They are biodegradable.
They generate electrical signals under mechanical load.
They have high thermal conductivity.
They are magnetic.
Explanation - Piezoelectric scaffolds convert mechanical stress from body movement into electrical signals that stimulate osteogenesis.
Correct answer is: They generate electrical signals under mechanical load.
Q.5 Which measurement technique is most appropriate for assessing the electrical conductivity of a hydrogel scaffold?
Atomic force microscopy
Four‑point probe method
Thermogravimetric analysis
Scanning electron microscopy
Explanation - The four‑point probe eliminates contact resistance, providing accurate conductivity measurements for soft materials like hydrogels.
Correct answer is: Four‑point probe method
Q.6 In neural tissue engineering, the term "electroactive" refers to:
Materials that change color under voltage.
Materials that can conduct ions or electrons.
Materials that are magnetic.
Materials that are biodegradable.
Explanation - Electroactive biomaterials support the flow of charge, crucial for interfacing with excitable cells such as neurons.
Correct answer is: Materials that can conduct ions or electrons.
Q.7 Which of the following biomaterials is intrinsically conductive and often used in peripheral nerve regeneration conduits?
Collagen
Polylactic acid (PLA)
Polyaniline
Hydroxyapatite
Explanation - Polyaniline is a conductive polymer that can be blended with natural polymers to create electrically active nerve guides.
Correct answer is: Polyaniline
Q.8 The "percolation threshold" in a composite scaffold refers to:
The minimum pore size for cell infiltration.
The critical filler concentration needed for a continuous conductive network.
The point at which the scaffold begins to degrade.
The temperature at which the material melts.
Explanation - Below the percolation threshold, conductive fillers are isolated; above it, they form a continuous path allowing charge transport.
Correct answer is: The critical filler concentration needed for a continuous conductive network.
Q.9 Which electrical stimulation parameter is most commonly varied to enhance myogenic differentiation in engineered muscle tissue?
Frequency
Voltage amplitude
Pulse width
All of the above
Explanation - Frequency, amplitude, and pulse width together shape the electrical cue that influences myoblast alignment and fusion.
Correct answer is: All of the above
Q.10 A major challenge when integrating metal electrodes into biodegradable scaffolds is:
Loss of mechanical strength.
Corrosion leading to toxic ion release.
Excessive electrical conductivity.
Increased transparency.
Explanation - Corrosion of metals like stainless steel can release ions that are harmful to surrounding tissue and compromise scaffold biocompatibility.
Correct answer is: Corrosion leading to toxic ion release.
Q.11 Which of the following best describes the role of "electrospinning" in creating tissue engineering scaffolds?
It melts polymers to form solid sheets.
It uses a high‑voltage electric field to draw nanofibers.
It deposits atoms layer‑by‑layer using a laser.
It chemically cross‑links polymers in solution.
Explanation - Electrospinning creates fibrous mats that can mimic extracellular matrix architecture and can incorporate conductive nanomaterials.
Correct answer is: It uses a high‑voltage electric field to draw nanofibers.
Q.12 In the context of cardiac patches, why is anisotropic electrical conductivity desirable?
It mimics the natural directionality of heart muscle fibers.
It improves scaffold degradation rate.
It reduces scaffold stiffness.
It enhances optical transparency.
Explanation - The heart conducts electrical signals preferentially along the fiber direction; anisotropic scaffolds support synchronized contraction.
Correct answer is: It mimics the natural directionality of heart muscle fibers.
Q.13 Which ion channel is commonly up‑regulated in stem cells when they receive electrical stimulation?
Voltage‑gated calcium channels
Sodium‑potassium pump
Aquaporin-1
Chloride channels
Explanation - Electrical stimulation opens voltage‑gated calcium channels, raising intracellular Ca²⁺ and influencing differentiation pathways.
Correct answer is: Voltage‑gated calcium channels
Q.14 A conductive hydrogel for neural tissue engineering is often prepared by combining alginate with:
Gold nanorods
Silicon carbide
Carbon nanotubes
Polytetrafluoroethylene
Explanation - Carbon nanotubes impart conductivity while maintaining the hydrogel's softness and biocompatibility.
Correct answer is: Carbon nanotubes
Q.15 The term "bioelectronic interface" refers to:
A device that converts mechanical energy into electrical energy.
A contact between electronic components and living tissue for signal exchange.
A method for sterilizing biomaterials using electricity.
A type of biodegradable polymer.
Explanation - Bioelectronic interfaces enable bidirectional communication between electronics and biological systems, crucial for tissue engineering implants.
Correct answer is: A contact between electronic components and living tissue for signal exchange.
Q.16 Which of the following scaffold fabrication methods inherently allows the creation of gradients in electrical conductivity?
Freeze‑drying
Layer‑by‑layer 3‑D printing
Sol‑gel casting
Electroplating
Explanation - 3‑D printing can vary the composition of each printed layer, enabling spatial control of conductive filler concentration.
Correct answer is: Layer‑by‑layer 3‑D printing
Q.17 When assessing the biocompatibility of an electrically active scaffold, which assay is most commonly used to evaluate cytotoxicity?
Live/Dead fluorescence assay
Fourier‑transform infrared spectroscopy
X‑ray diffraction
Contact angle measurement
Explanation - Live/Dead staining directly visualizes viable vs. dead cells after exposure to the scaffold, indicating cytotoxic effects.
Correct answer is: Live/Dead fluorescence assay
Q.18 Which conductive filler typically provides the highest conductivity per weight percent when mixed into a polymer matrix?
Silver nanoparticles
Silica microspheres
Calcium phosphate
Cellulose nanofibers
Explanation - Silver has the highest electrical conductivity among common fillers, achieving percolation at low loadings.
Correct answer is: Silver nanoparticles
Q.19 In the context of tissue engineering, the "electrochemical window" of a material describes:
The range of pH in which the material is stable.
The voltage range over which the material does not undergo electrolysis of water.
The frequency range of applied electrical stimulation.
The mechanical strain limits of the scaffold.
Explanation - Operating within the electrochemical window prevents gas generation and pH changes that can damage cells.
Correct answer is: The voltage range over which the material does not undergo electrolysis of water.
Q.20 Which of the following is a key advantage of using graphene over carbon nanotubes in conductive scaffolds?
Higher biodegradability
Better dispersion in aqueous media
Lower cost
Higher mechanical strength
Explanation - Graphene oxide is more hydrophilic and can be more uniformly distributed in polymer solutions, improving scaffold uniformity.
Correct answer is: Better dispersion in aqueous media
Q.21 A major factor limiting the long‑term use of metallic electrodes in implantable tissue engineering devices is:
Electrode corrosion
Low electrical resistance
Excessive flexibility
High optical transparency
Explanation - Corrosion can release metal ions, provoke inflammation, and degrade electrical performance over time.
Correct answer is: Electrode corrosion
Q.22 What is the purpose of adding a dielectric layer between a conductive polymer and living tissue?
To increase scaffold stiffness
To prevent direct electrical shorting while allowing capacitive coupling
To improve cell adhesion
To accelerate degradation
Explanation - A thin dielectric can act as a barrier to ions while still enabling charge transfer via capacitive coupling, reducing tissue damage.
Correct answer is: To prevent direct electrical shorting while allowing capacitive coupling
Q.23 Which type of electrical stimulation is most effective for promoting angiogenesis in engineered vascular grafts?
Direct current (DC)
Pulsed electromagnetic fields (PEMF)
Alternating current (AC) at 50 Hz
Static magnetic fields
Explanation - PEMFs have been shown to up‑regulate VEGF expression and stimulate new blood vessel formation.
Correct answer is: Pulsed electromagnetic fields (PEMF)
Q.24 Which biodegradable polymer is most frequently combined with conductive polymers to form electroactive scaffolds?
Polylactic acid (PLA)
Polyethylene terephthalate (PET)
Polyvinyl chloride (PVC)
Polyethylene glycol (PEG)
Explanation - PLA is biocompatible, degradable, and can be blended with conductive polymers like polypyrrole for electroactive scaffolds.
Correct answer is: Polylactic acid (PLA)
Q.25 When a conductive scaffold is placed in an aqueous cell culture medium, the measured impedance is influenced mainly by:
Scaffold pore size
Medium ionic strength
Scaffold color
Ambient temperature
Explanation - Ionic strength determines the solution resistance, which together with scaffold resistance determines total impedance.
Correct answer is: Medium ionic strength
Q.26 Which of the following best describes a “self‑healing” conductive hydrogel?
A hydrogel that restores its electrical conductivity after mechanical damage.
A hydrogel that dissolves in water.
A hydrogel that becomes magnetic when heated.
A hydrogel that changes color with pH.
Explanation - Self‑healing hydrogels contain reversible bonds that reform after fracture, regaining mechanical and conductive properties.
Correct answer is: A hydrogel that restores its electrical conductivity after mechanical damage.
Q.27 In the design of a bone‑regenerating scaffold, why might a researcher add a small amount of conductive graphene to a calcium‑phosphate matrix?
To improve the scaffold’s optical clarity.
To enhance osteogenic differentiation through electrical cues.
To increase scaffold degradation speed.
To make the scaffold magnetic.
Explanation - Electrical stimulation can up‑regulate bone‑forming genes; graphene provides the conductive pathways needed for this effect.
Correct answer is: To enhance osteogenic differentiation through electrical cues.
Q.28 Which of the following is NOT a typical method for functionalizing the surface of a conductive polymer to improve cell adhesion?
Covalent attachment of RGD peptides
Plasma treatment to increase surface roughness
Coating with a thin layer of silicone oil
Grafting of gelatin
Explanation - Silicone oil is hydrophobic and would hinder cell attachment, whereas the other methods increase bio‑affinity.
Correct answer is: Coating with a thin layer of silicone oil
Q.29 The term "electrospun nanofibrous mat" is most closely associated with which tissue engineering application?
Cardiac patches
Skin wound dressings
Bone scaffolds
Retinal implants
Explanation - Electrospun mats mimic the extracellular matrix of skin and can be loaded with conductive nanomaterials for wound healing with electrical stimulation.
Correct answer is: Skin wound dressings
Q.30 Which of the following phenomena explains the reduction of bacterial adhesion on electrically stimulated conductive surfaces?
Electrophoresis of bacterial cells away from the surface
Generation of localized heat
Electrostatic repulsion due to surface charge
Increased surface roughness
Explanation - Applied potentials can create surface charges that repel negatively charged bacterial membranes, reducing adhesion.
Correct answer is: Electrostatic repulsion due to surface charge
Q.31 A common way to monitor the real‑time electrical activity of cells cultured on a conductive scaffold is:
Scanning electron microscopy
Electrochemical impedance spectroscopy (EIS)
Live/Dead assay
Mass spectrometry
Explanation - EIS can detect changes in impedance caused by cell attachment, proliferation, and electrophysiological activity.
Correct answer is: Electrochemical impedance spectroscopy (EIS)
Q.32 For an implantable neural interface, which material property is most critical to prevent chronic inflammation?
High tensile strength
Low Young's modulus matching brain tissue
High electrical conductivity
Bright color
Explanation - Mechanical mismatch leads to micromotion‑induced inflammation; matching modulus reduces tissue response.
Correct answer is: Low Young's modulus matching brain tissue
Q.33 The primary reason why silicon nanowires are explored for intracellular recording is:
Their magnetic properties
Their ability to penetrate cell membranes with minimal damage
Their biodegradability
Their optical transparency
Explanation - Silicon nanowires can act as nanoelectrodes inserted into cells, providing high‑resolution recordings while preserving viability.
Correct answer is: Their ability to penetrate cell membranes with minimal damage
Q.34 When a conductive scaffold degrades in vivo, what is a potential concern regarding its degradation products?
They may become electrically insulating.
They could generate toxic ions or reactive species.
They will increase scaffold stiffness.
They will improve cell adhesion.
Explanation - Degradation of metals or some conductive polymers can release substances that provoke inflammation or cytotoxicity.
Correct answer is: They could generate toxic ions or reactive species.
Q.35 Which electrical stimulation waveform is typically used to mimic the natural firing pattern of cardiac myocytes during in‑vitro maturation?
Biphasic square pulses at 1 Hz
Continuous DC at 5 V
Triangular wave at 100 Hz
Randomized pulse train
Explanation - The heart beats at ~1 Hz; biphasic pulses reduce electrode polarization while replicating physiological timing.
Correct answer is: Biphasic square pulses at 1 Hz
Q.36 A conductive hydrogel composed of chitosan and polypyrrole is primarily useful for which of the following applications?
Load‑bearing bone scaffolds
Neural regeneration conduits
Vascular grafts requiring high burst pressure
Dental implants
Explanation - Chitosan offers biocompatibility and polypyrrole provides conductivity, together supporting nerve cell growth and signaling.
Correct answer is: Neural regeneration conduits
Q.37 What is the main advantage of using a “wireless” bio‑electronic scaffold over a wired one?
Higher electrical conductivity
Elimination of infection‑prone transcutaneous leads
Lower material cost
Increased scaffold porosity
Explanation - Wireless power transfer removes the need for percutaneous wires, reducing infection risk and improving patient comfort.
Correct answer is: Elimination of infection‑prone transcutaneous leads
Q.38 When designing a conductive scaffold for skeletal muscle, why is alignment of fibers important?
It improves oxygen diffusion.
It directs myotube formation along the force vector.
It increases scaffold degradation rate.
It enhances electrical resistance.
Explanation - Aligned fibers guide myoblast orientation, leading to functional, contractile muscle tissue.
Correct answer is: It directs myotube formation along the force vector.
Q.39 Which of the following is a potential drawback of using high concentrations of carbon nanotubes in polymer scaffolds?
Reduced mechanical strength
Increased opacity
Potential cytotoxicity due to aggregation
Excessive degradation speed
Explanation - Aggregated nanotubes can cause local stress concentrations and release reactive species harmful to cells.
Correct answer is: Potential cytotoxicity due to aggregation
Q.40 In the context of tissue engineering, the term "electroactive biomaterial" is synonymous with:
Biomaterial that changes shape under electric field
Biomaterial that conducts ions or electrons
Biomaterial that is magnetic
Biomaterial that degrades faster under voltage
Explanation - Electroactive biomaterials possess inherent electrical conductivity or can be polarized, enabling electrical communication with cells.
Correct answer is: Biomaterial that conducts ions or electrons
Q.41 Which testing method can simultaneously evaluate the mechanical and electrical properties of a scaffold under cyclic loading?
Dynamic mechanical analysis (DMA) with conductivity probe
Thermogravimetric analysis (TGA)
Differential scanning calorimetry (DSC)
X‑ray diffraction (XRD)
Explanation - DMA measures modulus while a built‑in electrode can monitor conductivity changes during cyclic strain.
Correct answer is: Dynamic mechanical analysis (DMA) with conductivity probe
Q.42 Why is the surface roughness of a conductive scaffold often increased during fabrication?
To improve electrical conductivity
To enhance cell attachment and proliferation
To reduce scaffold weight
To make the scaffold more transparent
Explanation - Rough surfaces increase available area for protein adsorption, promoting cell adhesion.
Correct answer is: To enhance cell attachment and proliferation
Q.43 A tissue engineer wants to create a scaffold that releases growth factors when an electrical stimulus is applied. Which material design principle would achieve this?
Embedding growth factors in a conductive polymer matrix that oxidizes on stimulation
Coating the scaffold with a non‑conductive silicone layer
Using a purely inert polymer without any charge carriers
Incorporating magnetic nanoparticles
Explanation - Electrical oxidation can trigger controlled release of encapsulated molecules from a conductive polymer network.
Correct answer is: Embedding growth factors in a conductive polymer matrix that oxidizes on stimulation
Q.44 Which of the following best explains why hydrogels are often chosen as the base material for conductive tissue scaffolds?
They are highly conductive by themselves.
They have a high water content, mimicking native tissue extracellular matrix.
They are rigid and provide structural support.
They are opaque and block light.
Explanation - Hydrogels’ high water content provides a physiologically relevant environment for cell survival while being compatible with conductive fillers.
Correct answer is: They have a high water content, mimicking native tissue extracellular matrix.
Q.45 In an electroactive bone scaffold, which cellular signaling pathway is most directly influenced by electrical cues?
Wnt/β‑catenin pathway
MAPK/ERK pathway
PI3K/Akt pathway
Notch signaling
Explanation - Electrical stimulation can up‑regulate Wnt signaling, promoting osteogenic differentiation and bone formation.
Correct answer is: Wnt/β‑catenin pathway
Q.46 What is the typical effect of applying a low‑frequency (1–10 Hz) alternating electric field to chondrocytes cultured on a conductive scaffold?
Inhibition of collagen synthesis
Promotion of extracellular matrix production
Induction of apoptosis
Conversion into osteoblasts
Explanation - Low‑frequency AC fields have been shown to stimulate glycosaminoglycan and collagen synthesis in cartilage tissue engineering.
Correct answer is: Promotion of extracellular matrix production
Q.47 Which of the following statements about the percolation theory in conductive composites is FALSE?
Percolation threshold decreases with higher aspect ratio fillers.
Above the percolation threshold, conductivity increases linearly with filler content.
Below the percolation threshold, the composite behaves as an insulator.
The theory predicts a sudden jump in conductivity near the threshold.
Explanation - Above the threshold, conductivity typically follows a power‑law increase, not a simple linear relationship.
Correct answer is: Above the percolation threshold, conductivity increases linearly with filler content.
Q.48 A researcher wants a scaffold that can be activated by an external magnetic field to generate electrical currents for stimulation. Which material combination would be most suitable?
Magnetite nanoparticles + conductive polymer matrix
Silica beads + biodegradable polymer
Gold nanorods + collagen
Polyethylene glycol + calcium phosphate
Explanation - Magnetite provides magnetic responsiveness; movement within a conductive matrix induces electric currents (magnetoelectric effect).
Correct answer is: Magnetite nanoparticles + conductive polymer matrix
Q.49 Which analytical technique is most appropriate for confirming the incorporation of graphene oxide into a polymer scaffold?
Raman spectroscopy
UV‑Vis spectroscopy
Gel permeation chromatography
Atomic absorption spectroscopy
Explanation - Raman provides characteristic D and G bands that identify graphene oxide within composites.
Correct answer is: Raman spectroscopy
Q.50 In a bio‑electronic implant, why is it important to limit the charge density delivered per phase of a stimulation pulse?
To avoid heating the tissue
To prevent irreversible electrochemical reactions at the electrode‑tissue interface
To reduce mechanical stress on the scaffold
To conserve battery life
Explanation - Exceeding safe charge density can cause water electrolysis, gas formation, and tissue damage.
Correct answer is: To prevent irreversible electrochemical reactions at the electrode‑tissue interface
Q.51 Which of the following best describes the concept of “electro‑spinning” in the fabrication of conductive scaffolds?
Using magnetic fields to align fibers.
Applying an electric field to draw polymer jets into nanofibers.
Heating polymers until they melt and flow.
Using laser ablation to pattern surfaces.
Explanation - Electrospinning uses high voltage to create fine fibers, which can be loaded with conductive nanomaterials.
Correct answer is: Applying an electric field to draw polymer jets into nanofibers.
Q.52 When evaluating the long‑term stability of an electroactive scaffold in vitro, which parameter is most indicative of degradation of its conductive network?
Decrease in Young's modulus
Increase in water uptake
Drop in electrical conductivity over time
Change in color
Explanation - Loss of conductive pathways directly reflects the degradation of the electroactive component.
Correct answer is: Drop in electrical conductivity over time
Q.53 A conductive polymer scaffold intended for cardiac tissue should ideally have which of the following mechanical properties?
Young's modulus > 1 GPa
Elastic modulus similar to myocardium (~10–20 kPa)
Hardness comparable to bone (~100 MPa)
Zero compressibility
Explanation - Matching the softness of heart tissue avoids mechanical mismatch and supports proper contraction.
Correct answer is: Elastic modulus similar to myocardium (~10–20 kPa)
Q.54 Which of the following statements about using gold nanowires in tissue engineering scaffolds is TRUE?
Gold nanowires are biodegradable.
They provide high conductivity with low percolation thresholds.
They are magnetic and can be manipulated with a magnet.
Gold nanowires are highly toxic to most cell types.
Explanation - Gold nanowires form conductive networks at low loadings due to their high aspect ratio and excellent conductivity.
Correct answer is: They provide high conductivity with low percolation thresholds.
Q.55 In an electrically stimulated cartilage construct, which extracellular matrix component is most commonly used as a biochemical marker for successful tissue formation?
Collagen type I
Aggrecan
Elastin
Keratin
Explanation - Aggrecan is a major proteoglycan in cartilage, indicating proper matrix deposition.
Correct answer is: Aggrecan
Q.56 What is the primary advantage of using a “biphasic” stimulation waveform over a monophasic one in implanted bio‑electronic devices?
Higher power consumption
Reduced electrode corrosion and polarization
Increased tissue heating
Simpler circuit design
Explanation - Biphasic pulses balance charge, minimizing irreversible electrochemical reactions at the electrode surface.
Correct answer is: Reduced electrode corrosion and polarization
Q.57 Which of the following is a typical characteristic of a scaffold designed for peripheral nerve repair?
Isotropic electrical conductivity
Aligned conductive channels to guide axon growth
High compressive strength
Hydrophobic surface
Explanation - Guidance cues—both topographical and electrical—direct regenerating axons toward their targets.
Correct answer is: Aligned conductive channels to guide axon growth
Q.58 In the context of tissue engineering, why is it beneficial for a conductive scaffold to be “self‑powered” (e.g., via piezoelectricity)?
It eliminates the need for external wiring or batteries.
It makes the scaffold biodegradable.
It increases the scaffold’s stiffness.
It changes the scaffold’s color.
Explanation - Self‑generated electrical signals from mechanical motion can stimulate cells without external power sources.
Correct answer is: It eliminates the need for external wiring or batteries.
Q.59 When incorporating silver nanowires into a polymer matrix for a conductive scaffold, what is a key concern regarding long‑term biocompatibility?
Silver nanowires are too large to be internalized by cells.
Silver ions can be released, leading to cytotoxicity.
Silver reduces scaffold porosity excessively.
Silver nanowires cause the scaffold to melt.
Explanation - Silver can leach as Ag⁺ ions, which are antimicrobial but also toxic to mammalian cells at high concentrations.
Correct answer is: Silver ions can be released, leading to cytotoxicity.
Q.60 Which of the following is NOT a common method for improving the dispersion of carbon‑based conductive fillers in aqueous polymer solutions?
Ultrasonication
Use of surfactants
High‑temperature melting
Functionalization with hydrophilic groups
Explanation - Melting is not suitable for aqueous systems; dispersion relies on mechanical agitation, surfactants, or chemical functionalization.
Correct answer is: High‑temperature melting
Q.61 A scaffold intended for bone tissue engineering displays a conductivity of 1 × 10⁻³ S/m. How does this compare to the conductivity of native bone tissue?
Much higher
Comparable
Much lower
Exactly the same
Explanation - Native cortical bone has conductivity in the range of 10⁻³–10⁻² S/m, so the scaffold’s value falls within physiological range.
Correct answer is: Comparable
Q.62 Which cellular process is most directly enhanced by the application of an electrical field to stem cells cultured on a conductive scaffold?
Apoptosis
Differentiation
Necrosis
Autophagy
Explanation - Electrical cues modulate signaling pathways that drive lineage-specific differentiation, especially in neural and muscular lineages.
Correct answer is: Differentiation
Q.63 When a conductive scaffold is implanted in vivo, which of the following measurements would best indicate successful integration with host tissue?
Stable impedance values over time
Gradual increase in scaffold weight
Change in scaffold color
Decrease in scaffold porosity
Explanation - Consistent impedance suggests the scaffold maintains its conductive pathways and forms a stable interface with tissue.
Correct answer is: Stable impedance values over time
Q.64 Which of the following best describes why a scaffold’s dielectric constant matters for electrical stimulation of cells?
It determines the scaffold’s mechanical strength.
It influences the distribution of the electric field within the scaffold.
It controls the scaffold’s degradation rate.
It affects the scaffold’s optical properties.
Explanation - A higher dielectric constant can store more electric charge, affecting how the field reaches cells.
Correct answer is: It influences the distribution of the electric field within the scaffold.
Q.65 In a conductive polymer‑based hydrogel, which functional group is most commonly introduced to increase water solubility?
Carboxyl (-COOH)
Methyl (-CH₃)
Phenyl (-C₆H₅)
Sulfate (-SO₄²⁻)
Explanation - Carboxyl groups enhance hydrophilicity and can form hydrogen bonds with water, improving swelling.
Correct answer is: Carboxyl (-COOH)
Q.66 Which of the following is a primary reason for using biodegradable conductive polymers (e.g., polypyrrole doped with lactic acid) in tissue engineering?
They never lose conductivity.
They avoid permanent foreign body presence after tissue regeneration.
They are magnetic.
They increase scaffold opacity.
Explanation - Biodegradable conductors provide temporary electrical cues and then safely degrade, eliminating long‑term implant issues.
Correct answer is: They avoid permanent foreign body presence after tissue regeneration.
Q.67 A researcher wants to evaluate how well neurons couple electrically with a conductive scaffold. Which measurement is most appropriate?
Patch‑clamp recording of neuronal membrane potential
Live/Dead staining
Scanning electron microscopy
Contact angle measurement
Explanation - Patch‑clamp directly measures electrical activity and coupling efficiency between neuron and scaffold.
Correct answer is: Patch‑clamp recording of neuronal membrane potential
Q.68 Which of the following conductive nanomaterials is known to possess both high conductivity and intrinsic antibacterial properties, making it attractive for wound‑healing scaffolds?
Carbon nanotubes
Silver nanowires
Graphene oxide
Polyaniline
Explanation - Silver releases Ag⁺ ions that are antibacterial while also providing electrical conductivity.
Correct answer is: Silver nanowires
Q.69 When a conductive scaffold is subjected to cyclic mechanical loading, what phenomenon can cause a gradual decline in its conductivity?
Thermal expansion
Filler network disruption (fatigue)
Increase in scaffold opacity
Decrease in water content
Explanation - Repeated strain can break conductive pathways, reducing overall conductivity.
Correct answer is: Filler network disruption (fatigue)
Q.70 Which type of electrode configuration is commonly used to deliver uniform electric fields across a 3‑D tissue construct?
Parallel plate electrodes
Point electrodes
Coiled wire electrodes
Ring electrodes
Explanation - Parallel plates generate a homogeneous field between them, ideal for uniform stimulation of 3‑D constructs.
Correct answer is: Parallel plate electrodes
Q.71 The term “bio‑impedance” in tissue engineering primarily reflects:
Mechanical stiffness of the scaffold
Electrical resistance and reactance of the cell‑scaffold system
Thermal conductivity of the scaffold
Optical transparency of the construct
Explanation - Bio‑impedance combines resistive and capacitive properties, providing insight into cell attachment and tissue formation.
Correct answer is: Electrical resistance and reactance of the cell‑scaffold system
Q.72 Which of the following is a potential advantage of using a conductive polymer blend (e.g., PEDOT:PSS) over metal electrodes for chronic neural interfaces?
Higher rigidity
Reduced tissue encapsulation
Higher electrical resistance
Increased magnetic susceptibility
Explanation - Soft, conformable polymeric electrodes match tissue mechanics, decreasing the foreign body response.
Correct answer is: Reduced tissue encapsulation
Q.73 When designing a scaffold for electro‑responsive drug release, which parameter should be modulated to trigger the release event?
Scaffold color
Electrical potential applied to the scaffold
Scaffold temperature
Scaffold mechanical stiffness
Explanation - Applying a voltage can cause redox reactions or conformational changes that release the drug.
Correct answer is: Electrical potential applied to the scaffold
Q.74 Which of the following statements about the use of piezoelectric ceramics (e.g., PZT) in tissue engineering is correct?
They are fully biodegradable.
They can convert mechanical stress into electrical signals that stimulate cells.
They are magnetic and used for MRI‑compatible devices.
They have low mechanical strength.
Explanation - Piezoelectric ceramics generate voltage under strain, providing endogenous electrical stimulation.
Correct answer is: They can convert mechanical stress into electrical signals that stimulate cells.
Q.75 What is the main reason for using a “hydrogel‑based conductive composite” rather than a dry polymer for soft tissue engineering?
Hydrogels are more conductive in dry conditions.
Hydrogels better mimic the hydrated environment of soft tissues.
Dry polymers have higher optical transparency.
Hydrogels are always mechanically stronger.
Explanation - The high water content of hydrogels provides a physiologically relevant milieu for cell survival and function.
Correct answer is: Hydrogels better mimic the hydrated environment of soft tissues.
Q.76 Which of the following electrical parameters is most directly linked to the stimulation of calcium influx in electrically excitable cells?
Electric field strength (V/m)
Pulse frequency (Hz)
Pulse duration (ms)
Waveform shape
Explanation - The magnitude of the field determines the depolarization needed to open voltage‑gated calcium channels.
Correct answer is: Electric field strength (V/m)
Q.77 A conductive scaffold for peripheral nerve repair is designed with a gradient of conductivity, high at one end and low at the other. What is the intended biological effect?
To create a mechanical load gradient.
To guide axonal growth directionally via electrophoretic cues.
To vary the degradation rate along the scaffold.
To change the scaffold’s color from one end to the other.
Explanation - A conductivity gradient establishes an electric field that can steer growing axons toward the higher conductivity region.
Correct answer is: To guide axonal growth directionally via electrophoretic cues.
Q.78 Which of the following is a commonly reported cytotoxic effect of excessive electrical stimulation on cultured cells?
Increased proliferation
Membrane rupture due to electroporation
Enhanced differentiation
Improved metabolic activity
Explanation - High electric fields can cause uncontrolled pore formation, damaging cell membranes and leading to cell death.
Correct answer is: Membrane rupture due to electroporation
Q.79 In the context of tissue‑engineered cardiac patches, what does the term “synchronization index” quantify?
The uniformity of pore size distribution.
The degree of coordinated contraction across the patch.
The electrical resistance of the scaffold.
The biodegradation rate of the material.
Explanation - A high synchronization index indicates that cardiomyocytes contract in unison, reflecting functional integration.
Correct answer is: The degree of coordinated contraction across the patch.
Q.80 Which of the following best explains why a scaffold containing polyaniline (PANI) may appear dark blue in color?
PANI absorbs in the ultraviolet region.
The oxidation state of PANI determines its visible light absorption.
PANI reacts with water to form a colored complex.
The scaffold’s porosity causes light scattering.
Explanation - The emeraldine salt form of PANI exhibits a blue color due to its electronic structure.
Correct answer is: The oxidation state of PANI determines its visible light absorption.
Q.81 A tissue engineer wants to ensure that an electrically active scaffold can be sterilized by gamma irradiation without losing conductivity. Which material choice is most suitable?
Metallic silver nanowires
Gold nanoparticles
Conductive polymers with stable doping
Graphene oxide without reduction
Explanation - Certain doped conductive polymers retain their electrical properties after gamma irradiation, unlike many metal nanostructures that may agglomerate.
Correct answer is: Conductive polymers with stable doping
Q.82 What is the main purpose of incorporating a “charge‑balancing” layer in a bio‑electronic implant?
To increase the overall device weight.
To prevent net DC charge buildup at the tissue interface.
To make the device visible under X‑ray.
To improve the mechanical strength of the implant.
Explanation - Charge‑balancing layers ensure that each stimulation pulse is biphasic, avoiding accumulation of charge that could cause tissue damage.
Correct answer is: To prevent net DC charge buildup at the tissue interface.
Q.83 When assessing the effect of electrical stimulation on stem cell differentiation, which molecular marker would most likely be measured for neuronal lineage?
Myosin heavy chain
β‑III tubulin (Tuj1)
Alkaline phosphatase
Collagen type I
Explanation - β‑III tubulin is a specific cytoskeletal protein expressed in neurons, used as a marker for neuronal differentiation.
Correct answer is: β‑III tubulin (Tuj1)
Q.84 Which of the following is a typical consequence of applying high‑frequency (>1 kHz) electrical stimulation to cardiac tissue engineered constructs?
Enhanced contractile force
Induction of arrhythmic activity
Inhibition of calcium channels
Improved scaffold degradation
Explanation - High‑frequency stimulation can disrupt the natural pacing of cardiomyocytes, leading to irregular contractions.
Correct answer is: Induction of arrhythmic activity
Q.85 A scaffold made from a blend of polycaprolactone (PCL) and polypyrrole is intended for bone regeneration. What is the primary role of the polypyrrole component?
To increase scaffold biodegradability
To provide electrical conductivity for stimulation of osteogenesis
To act as a cross‑linking agent
To make the scaffold magnetic
Explanation - Polypyrrole imparts conductivity, enabling electrical cues that promote bone formation.
Correct answer is: To provide electrical conductivity for stimulation of osteogenesis
Q.86 Which of the following measurement techniques can be used to map the spatial distribution of conductivity within a 3‑D scaffold?
Electrical impedance tomography (EIT)
Fourier transform infrared spectroscopy (FTIR)
Differential scanning calorimetry (DSC)
Thermogravimetric analysis (TGA)
Explanation - EIT reconstructs internal conductivity maps by applying currents and measuring resulting voltages.
Correct answer is: Electrical impedance tomography (EIT)
Q.87 In a conductive hydrogel used for cardiac tissue patches, why is it important to limit the swelling ratio of the gel?
To prevent excessive electrical resistance
To maintain mechanical integrity and avoid delamination from the heart surface
To increase the degradation rate
To improve optical clarity
Explanation - Excessive swelling can weaken the scaffold and cause it to detach from the beating heart.
Correct answer is: To maintain mechanical integrity and avoid delamination from the heart surface
Q.88 Which of the following is an advantage of using a “layered” scaffold architecture (conductive layer sandwiched between insulating layers) for neural interfacing?
It maximizes overall scaffold conductivity.
It isolates electrical stimulation to specific regions, reducing off‑target effects.
It makes the scaffold completely biodegradable.
It increases scaffold transparency.
Explanation - Insulating layers confine current flow, allowing targeted stimulation of desired neural populations.
Correct answer is: It isolates electrical stimulation to specific regions, reducing off‑target effects.
Q.89 A conductive polymer is doped with an anionic surfactant to improve its water solubility. Which property is most directly affected by this doping?
Mechanical stiffness
Electrical conductivity
Optical transparency
Thermal stability
Explanation - Doping introduces charge carriers, enhancing conductivity while also increasing solubility.
Correct answer is: Electrical conductivity
Q.90 Which of the following best explains why a higher percolation threshold is undesirable for a biodegradable conductive scaffold?
It requires more filler, which can compromise biodegradability and biocompatibility.
It leads to excessive scaffold stiffness.
It reduces scaffold porosity.
It makes the scaffold too transparent.
Explanation - More filler means higher load of potentially non‑degradable or toxic material, affecting scaffold performance.
Correct answer is: It requires more filler, which can compromise biodegradability and biocompatibility.
Q.91 When designing a scaffold for electromechanical actuation (e.g., muscle tissue), which material property must be optimized alongside conductivity?
Magnetic permeability
Elastic modulus matching native muscle (~10–100 kPa)
Thermal conductivity
Optical reflectivity
Explanation - Mechanical compliance compatible with muscle is essential for functional contraction and force transmission.
Correct answer is: Elastic modulus matching native muscle (~10–100 kPa)
Q.92 Which of the following statements regarding the use of conductive hydrogels in wound healing is correct?
They always accelerate scar formation.
They can enhance cell migration and angiogenesis when electrically stimulated.
They prevent any bacterial colonization.
They make the wound area opaque to light.
Explanation - Electrical cues from conductive hydrogels can promote the processes needed for rapid, healthy wound repair.
Correct answer is: They can enhance cell migration and angiogenesis when electrically stimulated.
Q.93 A tissue engineering device uses a flexible, conductive polymer electrode that conforms to brain tissue. Which failure mode is most likely if the Young's modulus of the electrode is significantly higher than that of the brain?
Electrode delamination
Mechanical irritation leading to gliosis
Loss of electrical conductivity
Rapid biodegradation
Explanation - Stiff electrodes cause micromotion‑induced damage, provoking a glial scar formation that impairs function.
Correct answer is: Mechanical irritation leading to gliosis
Q.94 In a conductive scaffold, the term “electrochemical stability window” determines:
The temperature range the scaffold can withstand.
The voltage range within which the scaffold does not undergo irreversible reactions.
The mechanical strain limits of the scaffold.
The pore size distribution.
Explanation - Operating within this window prevents degradation of the conductive material and harmful side reactions.
Correct answer is: The voltage range within which the scaffold does not undergo irreversible reactions.
Q.95 Which of the following is a primary reason to use a “biphasic” pulse rather than a monophasic pulse when stimulating cardiac tissue engineered constructs?
Biphasic pulses are easier to generate.
They reduce net charge injection, minimizing electrode corrosion and tissue damage.
They double the stimulation frequency.
They increase the scaffold’s mechanical strength.
Explanation - Balancing positive and negative phases avoids accumulation of charge that could lead to electrochemical damage.
Correct answer is: They reduce net charge injection, minimizing electrode corrosion and tissue damage.
Q.96 Which of the following best describes the purpose of adding a “hydrophilic” coating to a conductive polymer used in a tissue scaffold?
To increase the scaffold’s electrical resistance.
To improve cell adhesion and nutrient diffusion.
To make the scaffold more rigid.
To change the scaffold’s color.
Explanation - Hydrophilic surfaces attract proteins and water, facilitating cell attachment and transport of soluble factors.
Correct answer is: To improve cell adhesion and nutrient diffusion.
Q.97 A conductive scaffold is designed to release nitric oxide (NO) upon electrical stimulation. Which of the following mechanisms most likely enables this release?
Electrochemical reduction of a nitrite‑containing polymer matrix
Thermal heating of the scaffold
Magnetic field‑induced breakdown
Mechanical compression of the scaffold
Explanation - Applying a voltage can reduce nitrite groups to release NO, a bioactive gas that promotes vasodilation and angiogenesis.
Correct answer is: Electrochemical reduction of a nitrite‑containing polymer matrix
Q.98 Which of the following is a commonly used biodegradable conductive polymer for transient bio‑electronic applications?
Polypyrrole (PPy)
Poly(3,4‑ethylenedioxythiophene) (PEDOT)
Poly(3‑hexylthiophene) (P3HT)
Poly(lactic‑co‑glycolic acid) (PLGA) doped with conductive fillers
Explanation - PLGA is biodegradable; when combined with conductive nanofillers it forms a transient conductive scaffold.
Correct answer is: Poly(lactic‑co‑glycolic acid) (PLGA) doped with conductive fillers
Q.99 Why might a researcher choose a “low‑impedance” electrode for interfacing with a neural tissue construct?
To reduce the power consumption of the stimulation device.
To increase the mechanical stiffness of the scaffold.
To improve the visibility of the electrode under microscopy.
To prevent scaffold degradation.
Explanation - Low impedance minimizes voltage drop, allowing efficient current delivery with less power.
Correct answer is: To reduce the power consumption of the stimulation device.
Q.100 Which of the following phenomena can cause a temporary increase in the measured conductivity of a hydrogel scaffold during electrical stimulation?
Thermal expansion
Electro‑osmotic flow increasing ion transport
Polymer chain degradation
Color change of the scaffold
Explanation - Electric fields can drive fluid movement, enhancing ion mobility and apparent conductivity.
Correct answer is: Electro‑osmotic flow increasing ion transport
Q.101 In an in‑vitro model of skeletal muscle, what is the typical range of pulse amplitudes (voltage) used for electrical stimulation to promote myotube formation?
0.1–0.5 V
1–5 V
10–20 V
30–50 V
Explanation - Moderate voltages (1–5 V) are sufficient to depolarize myoblasts without causing damage.
Correct answer is: 1–5 V
Q.102 Which of the following conductive nanomaterials has the highest aspect ratio, making it especially effective at lowering the percolation threshold?
Silver nanoparticles
Graphene flakes
Carbon nanotubes
Gold nanospheres
Explanation - Their elongated shape provides long conductive pathways at low volume fractions.
Correct answer is: Carbon nanotubes
Q.103 When designing a bio‑electronic implant for chronic use, which property is most important for preventing fibrotic encapsulation?
High electrical conductivity
Low Young's modulus comparable to surrounding tissue
Bright color
Magnetic susceptibility
Explanation - Mechanical compliance reduces chronic inflammation and fibrotic capsule formation.
Correct answer is: Low Young's modulus comparable to surrounding tissue
Q.104 What is the primary function of a “charge‑injection” electrode in a bio‑electronic scaffold?
To release growth factors mechanically.
To deliver controlled electrical charge to the surrounding tissue.
To increase scaffold porosity.
To absorb excess water.
Explanation - Charge‑injection electrodes provide precise electrical stimuli that modulate cellular behavior.
Correct answer is: To deliver controlled electrical charge to the surrounding tissue.
Q.105 Which of the following is a reason to avoid using high‑frequency AC (>10 kHz) for stimulating chondrocytes in cartilage tissue engineering?
It can cause excessive heating.
It leads to rapid scaffold degradation.
It does not affect cell behavior.
It makes the scaffold brittle.
Explanation - High‑frequency currents can generate Joule heating, potentially damaging heat‑sensitive cartilage cells.
Correct answer is: It can cause excessive heating.
Q.106 A conductive polymer scaffold is doped with a bio‑compatible anion to improve its performance. Which of the following anions is commonly used for this purpose?
Chloride (Cl⁻)
Perchlorate (ClO₄⁻)
Poly(styrenesulfonate) (PSS⁻)
Fluoride (F⁻)
Explanation - PSS⁻ is a large, stable anion that enhances conductivity while remaining biocompatible.
Correct answer is: Poly(styrenesulfonate) (PSS⁻)
Q.107 Which of the following statements about the use of “magnetoelectric” composites in tissue engineering is TRUE?
They require external magnetic fields to generate electrical potentials within the scaffold.
They are always biodegradable.
They cannot be used for neural applications.
They have no effect on cell behavior.
Explanation - Magnetoelectric materials convert magnetic stimuli into electric fields, enabling wireless stimulation.
Correct answer is: They require external magnetic fields to generate electrical potentials within the scaffold.
Q.108 In a conductive scaffold designed for skeletal muscle regeneration, what is the expected effect of applying a cyclic stretch together with electrical stimulation?
Reduced myotube formation
Enhanced alignment and maturation of muscle fibers
Increased scaffold degradation rate
Decreased cell viability
Explanation - Combined mechanical and electrical cues synergistically promote myogenic differentiation and fiber organization.
Correct answer is: Enhanced alignment and maturation of muscle fibers
Q.109 Which of the following is a key advantage of using a “self‑assembling peptide” that forms a conductive nanofiber network for tissue engineering?
It provides magnetic properties.
It can be formed under mild, cell‑friendly conditions.
It is highly rigid and non‑degradable.
It blocks ion transport.
Explanation - Self‑assembling peptides can gel at physiological pH and temperature, allowing cell encapsulation without harsh processing.
Correct answer is: It can be formed under mild, cell‑friendly conditions.
Q.110 What is the primary reason for using a “low‑impedance” recording electrode when monitoring action potentials from neurons cultured on a conductive scaffold?
To increase the mechanical strength of the scaffold.
To reduce thermal noise and improve signal quality.
To make the electrode visible under fluorescence microscopy.
To accelerate scaffold degradation.
Explanation - Low impedance minimizes Johnson noise, yielding clearer electrophysiological recordings.
Correct answer is: To reduce thermal noise and improve signal quality.
Q.111 Which of the following is a typical effect of exposing conductive polymer scaffolds to UV light for sterilization?
Permanent increase in conductivity
Potential degradation of polymer backbone, reducing conductivity
Change in scaffold color to red
Increase in mechanical stiffness
Explanation - UV radiation can break conjugated bonds in conductive polymers, diminishing their electrical properties.
Correct answer is: Potential degradation of polymer backbone, reducing conductivity
Q.112 A researcher wants to evaluate the effect of scaffold conductivity on osteoblast proliferation. Which experimental control is most appropriate?
A non‑conductive scaffold made of the same polymer matrix.
A scaffold with double the pore size.
A scaffold with higher mechanical stiffness.
A scaffold soaked in saline for 24 h.
Explanation - Keeping all variables identical except conductivity isolates the effect of electrical properties on cell behavior.
Correct answer is: A non‑conductive scaffold made of the same polymer matrix.
Q.113 Which of the following statements accurately describes the role of “bio‑electrochemical coupling” in tissue engineered constructs?
It refers to the mechanical bonding between scaffold fibers.
It describes the interaction between electrical signals and biochemical pathways in cells.
It is the process of converting light into electricity.
It indicates the thermal insulation properties of the scaffold.
Explanation - Bio‑electrochemical coupling involves how electrical cues influence signaling cascades, gene expression, and metabolic processes.
Correct answer is: It describes the interaction between electrical signals and biochemical pathways in cells.
Q.114 In a conductive scaffold for peripheral nerve regeneration, which neurotransmitter release is most likely enhanced by electrical stimulation?
Acetylcholine
Dopamine
Norepinephrine
Serotonin
Explanation - Acetylcholine is a primary neurotransmitter at neuromuscular junctions; electrical cues can increase its release during regeneration.
Correct answer is: Acetylcholine
Q.115 When measuring the conductivity of a hydrated conductive scaffold, which factor must be accounted for to obtain an accurate intrinsic material conductivity?
The scaffold’s color
The ionic conductivity of the surrounding medium
The scaffold’s magnetic susceptibility
The scaffold’s optical absorption
Explanation - The surrounding electrolyte contributes to measured resistance; correcting for this yields the scaffold’s true conductivity.
Correct answer is: The ionic conductivity of the surrounding medium
Q.116 Which of the following is a major benefit of using a “soft‑lithography” technique to pattern conductive features on a polymer scaffold?
It creates highly conductive bulk material.
It allows precise micro‑scale patterning without high temperatures that could damage biomolecules.
It reduces the scaffold’s degradation rate.
It makes the scaffold magnetic.
Explanation - Soft‑lithography uses elastomer stamps at low temperatures, preserving bioactive components while defining conductive pathways.
Correct answer is: It allows precise micro‑scale patterning without high temperatures that could damage biomolecules.
Q.117 A conductive scaffold designed for cardiac patches must maintain conductivity over a period of at least:
1 week
1 month
6 months
5 years
Explanation - Functional cardiac repair typically requires the scaffold to stay conductive throughout the remodeling phase, which can extend to several months.
Correct answer is: 6 months
Q.118 Which of the following is a commonly reported advantage of integrating gold nanorods into conductive polymer scaffolds?
They make the scaffold biodegradable.
They enhance electrical conductivity and can be tuned for optical properties.
They significantly increase scaffold porosity.
They reduce the scaffold’s mechanical strength.
Explanation - Gold nanorods provide high conductivity and surface plasmon resonance, enabling multifunctional scaffolds.
Correct answer is: They enhance electrical conductivity and can be tuned for optical properties.
Q.119 In the context of tissue‑engineered constructs, the term “electro‑spontaneous polarization” most closely refers to:
Mechanical stretching of the scaffold.
Self‑generation of an electric field due to material asymmetry.
Optical emission under UV light.
Thermal expansion.
Explanation - Certain piezoelectric or ferroelectric biomaterials develop internal polarization without external stimulus.
Correct answer is: Self‑generation of an electric field due to material asymmetry.
Q.120 Which of the following cell types is most commonly used to assess the neuro‑compatibility of a conductive scaffold?
Myoblasts
Chondrocytes
Neural stem cells (NSCs)
Fibroblasts
Explanation - NSCs can differentiate into neurons and glia, providing a relevant model for neural scaffold compatibility.
Correct answer is: Neural stem cells (NSCs)
Q.121 A conductive polymer scaffold is doped with anionic surfactants to increase its water solubility. How does this doping affect its biocompatibility?
It always makes the scaffold toxic.
It generally improves biocompatibility by enhancing water uptake and reducing hydrophobicity.
It makes the scaffold magnetic.
It reduces the scaffold’s mechanical strength to zero.
Explanation - Increased hydrophilicity promotes protein adsorption and cell adhesion while maintaining conductivity.
Correct answer is: It generally improves biocompatibility by enhancing water uptake and reducing hydrophobicity.
Q.122 When measuring the electrical properties of a 3‑D conductive scaffold, why might a researcher use a “four‑probe” configuration instead of a “two‑probe” setup?
Four‑probe eliminates contact resistance errors, giving a more accurate measurement.
Four‑probe is cheaper to implement.
Two‑probe cannot measure conductivity at all.
Four‑probe provides temperature data automatically.
Explanation - The outer probes source current, while the inner probes measure voltage drop, separating sample resistance from contact resistance.
Correct answer is: Four‑probe eliminates contact resistance errors, giving a more accurate measurement.
Q.123 Which of the following statements best describes why a scaffold’s “dielectric constant” matters for electrical stimulation of cells?
A higher dielectric constant reduces mechanical stiffness.
It influences how much electric field is stored within the scaffold material.
It determines the scaffold’s biodegradation rate.
It changes the scaffold’s color.
Explanation - Dielectric constant dictates capacitive behavior, affecting the distribution and strength of the electric field experienced by cells.
Correct answer is: It influences how much electric field is stored within the scaffold material.