Q.1 Which of the following electrical stimulation parameters is most commonly used to promote angiogenesis in engineered tissue constructs?
Continuous DC at 1 mA
Pulsed AC at 200 Hz
Pulsed DC at 50 Hz, 1 V/cm
High‑frequency AC at 1 kHz
Explanation - Pulsed direct current (DC) at low frequency (≈50 Hz) and moderate field strength (~1 V/cm) has been shown to enhance endothelial cell proliferation and new vessel formation in vitro and in vivo.
Correct answer is: Pulsed DC at 50 Hz, 1 V/cm
Q.2 What is the primary bioelectric signal generated by cardiac pacemaker cells that drives heart rhythm?
Action potential
Synaptic vesicle release
G‑protein coupled receptor activation
Long‑term potentiation
Explanation - Cardiac pacemaker cells generate spontaneous action potentials that propagate through the heart’s conduction system, maintaining rhythmic contraction.
Correct answer is: Action potential
Q.3 Which material is commonly used as an electrically conductive scaffold for nerve regeneration?
Polylactic acid (PLA)
Polycaprolactone (PCL)
Gold nanoparticles
Polydimethylsiloxane (PDMS)
Explanation - Gold nanoparticles can be incorporated into polymeric scaffolds to provide electrical conductivity and promote neurite outgrowth, aiding peripheral nerve repair.
Correct answer is: Gold nanoparticles
Q.4 In tissue‑engineering microfluidic devices, what is the purpose of applying an electric field across a porous membrane?
To sterilize the device
To induce convective flow and enhance cell‑matrix interactions
To measure membrane resistance
To label cells with fluorescent dyes
Explanation - Electrokinetic forces, such as electroosmosis, can drive fluid through porous membranes, improving nutrient transport and cell alignment within microfluidic tissue constructs.
Correct answer is: To induce convective flow and enhance cell‑matrix interactions
Q.5 What role does the piezoelectric effect play in bone tissue engineering?
It provides structural support to the scaffold
It generates electrical signals upon mechanical loading that stimulate osteogenesis
It degrades the scaffold material
It acts as a magnetic resonance contrast agent
Explanation - Piezoelectric materials like hydroxyapatite composites produce micro‑volt signals when mechanically stressed, which can up‑regulate bone‑forming cell activity.
Correct answer is: It generates electrical signals upon mechanical loading that stimulate osteogenesis
Q.6 Which parameter is critical when designing a wearable electrical stimulation patch for skin wound healing?
Electrode material conductivity
Pulse duration of 0.1–10 ms
Ambient temperature
Device weight above 100 g
Explanation - Short pulse durations (milliseconds) are preferred to deliver high‑frequency biphasic currents that stimulate fibroblast proliferation without causing tissue damage.
Correct answer is: Pulse duration of 0.1–10 ms
Q.7 In neural interface design, why are micro‑scale electrodes favored over macro‑scale ones?
They are cheaper to manufacture
They reduce the risk of infection
They provide higher spatial resolution and lower impedance
They require less power
Explanation - Smaller electrodes couple more effectively to individual neurons, allowing precise stimulation and recording while minimizing tissue damage.
Correct answer is: They provide higher spatial resolution and lower impedance
Q.8 What is a major advantage of using graphene in biopotential recording electrodes?
It is biodegradable
It offers ultra‑high electrical conductivity and flexibility
It is magnetic
It dissolves in aqueous media
Explanation - Graphene’s superior conductivity and mechanical flexibility make it ideal for conformal, high‑sensitivity recording of bioelectric signals.
Correct answer is: It offers ultra‑high electrical conductivity and flexibility
Q.9 Which of the following is NOT a typical effect of electrical stimulation on stem cell differentiation?
Enhanced osteogenic differentiation
Promotion of chondrogenic lineage
Induction of apoptosis in undifferentiated cells
Up‑regulation of connexin expression
Explanation - Electrical cues generally promote lineage specification and enhance intercellular communication; they do not typically trigger apoptosis in stem cells under controlled parameters.
Correct answer is: Induction of apoptosis in undifferentiated cells
Q.10 What is the function of a Faraday cage in bioelectronic device testing?
To enhance device sensitivity
To shield the device from external electromagnetic interference
To provide a thermal environment
To act as a power supply
Explanation - A Faraday cage blocks external electric fields, ensuring that measured bioelectric signals originate from the device itself.
Correct answer is: To shield the device from external electromagnetic interference
Q.11 Which frequency band of electrical stimulation is most effective for promoting Schwann cell migration in peripheral nerve repair?
Low‑frequency (<5 Hz)
Intermediate (10–30 Hz)
High‑frequency (200–500 Hz)
Ultra‑high (kHz range)
Explanation - Intermediate frequencies mimic physiological myelin potentials, encouraging Schwann cells to align and support axon regeneration.
Correct answer is: Intermediate (10–30 Hz)
Q.12 Which sensing technology is commonly integrated into 3D‑printed bone scaffolds to monitor electrical impedance changes during healing?
Capacitive sensors
Resistive strain gauges
Piezoelectric transducers
Inductive coils
Explanation - Resistive sensors can detect changes in tissue conductivity, indicating scaffold integration and new bone formation.
Correct answer is: Resistive strain gauges
Q.13 What is the typical voltage range used to stimulate cardiac tissue ex vivo without causing arrhythmias?
0.1–0.3 V
0.5–1 V
2–5 V
10–20 V
Explanation - Low‑voltage biphasic pulses around 0.5–1 V are sufficient to depolarize cardiomyocytes while minimizing pro‑arrhythmic risk.
Correct answer is: 0.5–1 V
Q.14 Why is impedance spectroscopy useful in evaluating the quality of engineered skin constructs?
It measures electrical resistance only
It provides information about tissue porosity and cell density
It detects bacterial contamination
It determines the mechanical stiffness of the scaffold
Explanation - Impedance spectra correlate with cell packing, ECM composition, and scaffold integrity, serving as a non‑invasive health indicator.
Correct answer is: It provides information about tissue porosity and cell density
Q.15 Which of the following is a primary safety concern when implanting electrical bio‑devices in the brain?
Thermal heating
Radiation exposure
Chemical toxicity of electrode material
Increased blood pressure
Explanation - Electrical currents can generate localized heat, potentially damaging neural tissue; thus power limits are strictly regulated.
Correct answer is: Thermal heating
Q.16 How does electrical field stimulation influence fibroblast migration during wound healing?
It repels fibroblasts from the wound site
It guides fibroblasts toward the leading edge of the wound
It induces fibroblast apoptosis
It has no effect on fibroblasts
Explanation - Electric fields create galvanotaxis cues that direct fibroblast movement toward the wound margin, facilitating closure.
Correct answer is: It guides fibroblasts toward the leading edge of the wound
Q.17 What is the role of micro‑electrodes in cardiac tissue engineering?
To provide mechanical support
To deliver electrical pacing signals to sync contractions
To sense blood pressure
To deliver drugs via iontophoresis
Explanation - Micro‑electrodes can pace engineered cardiac patches, ensuring coordinated beating when implanted.
Correct answer is: To deliver electrical pacing signals to sync contractions
Q.18 Which property of collagen scaffolds is most affected by applying a low‑frequency electric field?
Molecular weight
Fiber alignment
pH
Thermal stability
Explanation - Electric fields can align collagen fibers, mimicking the anisotropic structure of native tissues and guiding cell alignment.
Correct answer is: Fiber alignment
Q.19 What is a common method to reduce the impedance of carbon‑based electrodes used in neural recording?
Increasing electrode size
Coating with PEDOT
Using high‑frequency AC
Placing electrodes in saline solution
Explanation - Poly(3,4‑ethylenedioxythiophene) (PEDOT) coatings lower impedance and improve charge transfer at the electrode–tissue interface.
Correct answer is: Coating with PEDOT
Q.20 Which phenomenon explains how cells sense and respond to electric fields during regeneration?
Phototaxis
Electrotaxis
Chemotaxis
Mechanotaxis
Explanation - Electrotaxis is the directed migration of cells toward the cathode or anode under applied electric fields, aiding tissue repair.
Correct answer is: Electrotaxis
Q.21 What is the main advantage of using biodegradable conductive polymers for scaffold fabrication?
They never degrade
They provide long‑term conductivity after implantation
They can conduct electricity while gradually resorbing, avoiding removal surgery
They are cheaper than metals
Explanation - Biodegradable conductors such as polypyrrole can support early tissue growth and then safely degrade, reducing foreign body presence.
Correct answer is: They can conduct electricity while gradually resorbing, avoiding removal surgery
Q.22 Which electrical parameter is most critical for preventing electrolysis at electrode interfaces?
Pulse width
Frequency
Amplitude
Total charge per phase
Explanation - Limiting the charge per phase ensures that the applied potential stays within the water window, preventing electrochemical reactions that damage tissue.
Correct answer is: Total charge per phase
Q.23 How does electrical stimulation influence collagen deposition in engineered cartilage?
It decreases collagen type II production
It increases glycosaminoglycan content only
It enhances collagen type II synthesis and alignment
It has no effect
Explanation - Controlled electrical cues up‑regulate chondrogenic markers, leading to improved collagen type II production and oriented fiber deposition.
Correct answer is: It enhances collagen type II synthesis and alignment
Q.24 What is the purpose of incorporating micro‑channels in electrically conductive hydrogel scaffolds?
To prevent electrical conduction
To guide vascular infiltration and nutrient transport
To increase scaffold stiffness
To serve as optical fibers
Explanation - Micro‑channels provide paths for cells and vessels, enhancing integration while maintaining electrical pathways for stimulation.
Correct answer is: To guide vascular infiltration and nutrient transport
Q.25 Which of the following best describes the concept of bioelectronic medicine?
Using bioinformatics to design electrical circuits
Using electrical devices to treat diseases by modulating biological signals
Using mechanical devices to deliver drugs
Using chemical sensors to measure blood glucose
Explanation - Bioelectronic medicine involves implantable or wearable electronics that interact with the nervous system or other bioelectric pathways to treat conditions.
Correct answer is: Using electrical devices to treat diseases by modulating biological signals
Q.26 Which parameter determines the depth of penetration of electrical stimulation in soft tissue?
Electrode size
Electric field strength
Frequency
Pulse duration
Explanation - The magnitude of the electric field governs how far the stimulation effects propagate within conductive tissue media.
Correct answer is: Electric field strength
Q.27 What is the typical range of electric field strengths used in bone tissue engineering to stimulate osteogenesis?
1–10 V/m
50–100 V/m
200–500 V/m
1–5 kV/m
Explanation - Low‑intensity electric fields (≈1–10 V/m) are sufficient to activate osteogenic pathways without causing adverse effects.
Correct answer is: 1–10 V/m
Q.28 Why are platinum‑iridium electrodes preferred for long‑term neural interfaces?
They are transparent
They resist corrosion and maintain low impedance
They are magnetic
They dissolve in body fluids
Explanation - PtIr alloys exhibit excellent electrochemical stability and biocompatibility, ensuring reliable long‑term performance.
Correct answer is: They resist corrosion and maintain low impedance
Q.29 Which phenomenon allows tissue‑engineered constructs to generate their own bioelectric fields during growth?
Piezoelectricity
Electrochemical gradients
Magnetoresistance
Thermal conduction
Explanation - Cells establish ion gradients across membranes, producing endogenous bioelectric fields that influence migration and differentiation.
Correct answer is: Electrochemical gradients
Q.30 Which technology is most effective for delivering spatially patterned electrical stimulation to a 3D tissue construct?
Uniform surface electrode
Multi‑channel electrode array
Single‑point needle electrode
Magnetic induction coil
Explanation - Arrays provide localized, controllable stimulation spots, enabling precise patterning within a 3D scaffold.
Correct answer is: Multi‑channel electrode array
Q.31 What is a key advantage of using inductive coupling in wireless power transfer for implantable bioelectronics?
It requires direct contact with the battery
It allows deep tissue penetration without wires
It increases the risk of tissue heating
It is only effective at extremely low frequencies
Explanation - Inductive coupling transmits energy across small gaps, enabling battery‑free operation of implanted devices.
Correct answer is: It allows deep tissue penetration without wires
Q.32 Which of the following best describes electroporation?
Using heat to increase permeability
Applying a high‑frequency electric field to permeabilize cell membranes
Injecting drugs mechanically
Using magnetic fields to open pores
Explanation - Electroporation uses short, high‑voltage pulses to transiently create pores in cell membranes, facilitating gene delivery or drug uptake.
Correct answer is: Applying a high‑frequency electric field to permeabilize cell membranes
Q.33 What is the primary role of microelectrodes in cardiac organoid development?
To measure temperature
To provide mechanical support
To monitor and stimulate electrical activity
To deliver oxygen
Explanation - Microelectrodes capture action potentials and can pace organoids to maintain physiological beating patterns.
Correct answer is: To monitor and stimulate electrical activity
Q.34 Which technique is used to quantify the electrical conductivity of engineered tissues?
Four‑point probe measurement
Mass spectrometry
X‑ray diffraction
Fluorescence imaging
Explanation - The four‑point probe technique accurately measures bulk conductivity, minimizing contact resistance errors.
Correct answer is: Four‑point probe measurement
Q.35 Which property of gold nanowire electrodes makes them suitable for neural recording?
High resistivity
Large surface area and flexible conductivity
Inability to adhere to tissue
Thermal instability
Explanation - Gold nanowires provide a large electroactive surface and maintain conductivity while conforming to tissue curvature.
Correct answer is: Large surface area and flexible conductivity
Q.36 What is a common method to reduce biofouling on implanted electrodes?
Applying a hydrophobic polymer coating
Increasing current density
Using high‑temperature sterilization
Adding metallic ions to the environment
Explanation - Hydrophobic coatings deter protein adsorption, decreasing biofouling and maintaining signal fidelity.
Correct answer is: Applying a hydrophobic polymer coating
Q.37 Which frequency range is used in electrical stimulation protocols for spinal cord injury rehabilitation?
0.1–1 Hz
5–20 Hz
50–100 Hz
1–5 kHz
Explanation - Low‑frequency stimulation (5–20 Hz) mimics natural spinal reflexes and facilitates motor pathway activation.
Correct answer is: 5–20 Hz
Q.38 What is the main benefit of using ion‑tunable conductive hydrogels in tissue engineering?
They increase degradation rate
They allow reversible control of conductivity
They produce magnetic fields
They are non‑conductive
Explanation - Ion concentration can be modulated to switch conductivity on/off, enabling dynamic stimulation protocols.
Correct answer is: They allow reversible control of conductivity
Q.39 Which of the following best describes the water window in electrochemical stimulation?
The frequency range where water conducts
The voltage range between hydrogen and oxygen evolution potentials
The time window for pulse application
The range of safe temperatures
Explanation - Operating within the water window (~−0.6 V to +0.8 V vs. Ag/AgCl) avoids electrolysis and tissue damage.
Correct answer is: The voltage range between hydrogen and oxygen evolution potentials
Q.40 What is the effect of electrical stimulation on mesenchymal stem cells (MSCs) cultured on a graphene scaffold?
It inhibits MSC proliferation
It promotes osteogenic differentiation via RUNX2 activation
It causes MSC death
It has no effect
Explanation - Electrical cues on conductive scaffolds up‑regulate osteogenic transcription factors such as RUNX2, enhancing bone formation.
Correct answer is: It promotes osteogenic differentiation via RUNX2 activation
Q.41 Which analytical technique is used to monitor the real‑time charge transfer at the electrode–tissue interface?
Cyclic voltammetry
Dynamic light scattering
Differential scanning calorimetry
Atomic force microscopy
Explanation - Cyclic voltammetry provides information on electrochemical behavior and interfacial charge transfer processes.
Correct answer is: Cyclic voltammetry
Q.42 Which electrical stimulus pattern has been shown to enhance vascular endothelial growth factor (VEGF) expression in MSCs?
Continuous DC at 1 mA
Pulsed AC at 50 Hz
Biphasic square pulses at 20 Hz, 200 µs
Random noise stimulation
Explanation - Low‑frequency biphasic pulses stimulate VEGF production, promoting angiogenesis in engineered tissues.
Correct answer is: Biphasic square pulses at 20 Hz, 200 µs
Q.43 Why is the use of flexible electronics critical in neural prosthetics?
They are cheaper
They conform to brain curvature, reducing mechanical mismatch
They cannot be sterilized
They provide higher electrical resistance
Explanation - Flexibility reduces tissue damage and glial scarring, improving long‑term device performance.
Correct answer is: They conform to brain curvature, reducing mechanical mismatch
Q.44 What is the primary mechanism by which electrical stimulation accelerates cartilage repair?
Inducing apoptosis
Increasing glycosaminoglycan synthesis
Reducing collagen type II expression
Blocking cell proliferation
Explanation - Electrical cues up‑regulate anabolic pathways, boosting GAG production critical for cartilage matrix formation.
Correct answer is: Increasing glycosaminoglycan synthesis
Q.45 Which parameter is critical when designing an electrospun conductive scaffold for muscle tissue engineering?
Fiber diameter
Scaffold porosity
Electrical conductivity of the fibers
All of the above
Explanation - Fiber diameter influences cell alignment, porosity affects nutrient transport, and conductivity drives electrical signaling.
Correct answer is: All of the above
Q.46 What is the main advantage of using a three‑terminal potentiostat in bioelectronic device testing?
It reduces cost
It eliminates solution resistance effects
It requires no reference electrode
It works only in vacuum
Explanation - The reference electrode monitors potential, minimizing errors due to solution resistance in impedance measurements.
Correct answer is: It eliminates solution resistance effects
Q.47 Which of the following describes the 'water window' in electrochemistry?
The temperature range where water boils
The potential window where water is stable against oxidation and reduction
The voltage range for neural stimulation
The frequency range for optical imaging
Explanation - Within the water window (~−0.6 V to +0.8 V vs. Ag/AgCl), no water electrolysis occurs, preventing gas bubble formation.
Correct answer is: The potential window where water is stable against oxidation and reduction
Q.48 Which factor is least important when evaluating the long‑term biocompatibility of an implantable electrode?
Electrode material corrosion rate
Mechanical flexibility
Electrical resistance
Color of the electrode
Explanation - Color does not affect biocompatibility; material degradation, flexibility, and resistance are critical determinants.
Correct answer is: Color of the electrode
Q.49 Which electrical parameter is directly correlated with the magnitude of electrotaxis?
Temperature
Electric field strength
Light intensity
Chemical gradient
Explanation - Higher field strengths increase the directional migration speed of cells during electrotaxis.
Correct answer is: Electric field strength
Q.50 What is a typical application of optogenetics combined with electrical stimulation in tissue engineering?
To visualize bone density
To control cell contractility via light‑activated ion channels
To measure electrical impedance
To sterilize scaffolds
Explanation - Optogenetic tools can be activated by light while electrical cues guide differentiation, creating sophisticated control over tissue maturation.
Correct answer is: To control cell contractility via light‑activated ion channels
Q.51 Which of the following best explains why micro‑electrodes are preferred for chronic neural recording?
They are less expensive
They reduce the foreign body response by matching neural tissue impedance
They are larger in size
They require high current
Explanation - Smaller electrodes lower the mechanical mismatch and minimize glial scarring, sustaining signal quality over time.
Correct answer is: They reduce the foreign body response by matching neural tissue impedance
Q.52 What is the primary mechanism of action for magnetoelectric scaffolds in bone regeneration?
Direct magnetic field stimulation of osteocytes
Conversion of ambient magnetic fields into local electrical stimuli that promote osteogenesis
Thermal heating of bone
Providing a scaffold for blood clot formation
Explanation - Magnetoelectric materials generate electrical potentials when exposed to magnetic fields, stimulating bone‑forming cells.
Correct answer is: Conversion of ambient magnetic fields into local electrical stimuli that promote osteogenesis
Q.53 Which characteristic of a neural interface is most critical for preventing high‑frequency noise contamination?
Large electrode area
Low‑noise amplifier
High electrode impedance
Magnetic shielding
Explanation - Amplifiers with low intrinsic noise preserve the fidelity of the recorded bioelectric signals, especially at high frequencies.
Correct answer is: Low‑noise amplifier
Q.54 How does electrical stimulation influence the alignment of fibroblasts in wound healing?
It randomizes cell orientation
It aligns cells parallel to the electric field lines
It induces cell death
It has no effect
Explanation - Fibroblasts exhibit galvanotaxis, aligning themselves along the electric field, which promotes organized extracellular matrix deposition.
Correct answer is: It aligns cells parallel to the electric field lines
Q.55 Which type of electrical stimulation is considered best for promoting neural regeneration after spinal cord injury?
High‑frequency AC
Low‑frequency biphasic DC
Static DC
Randomized pulse patterns
Explanation - Low‑frequency biphasic currents (≈30 Hz) support axon sprouting while minimizing tissue damage.
Correct answer is: Low‑frequency biphasic DC
Q.56 What is the main benefit of using a bioresorbable electrode in transient bioelectronics?
It can be retrieved by surgery
It degrades over time eliminating the need for removal
It provides permanent recording
It increases cost significantly
Explanation - Bioresorbable electrodes dissolve after their functional period, avoiding chronic implant complications.
Correct answer is: It degrades over time eliminating the need for removal
Q.57 Which material property is crucial for a conductive hydrogel used in cardiac tissue scaffolds?
High optical transparency
Thermal stability above 100 °C
Electrical conductivity in the physiological range (µS–mS/cm)
High brittleness
Explanation - Conductivity within the physiological range allows electrical coupling while maintaining hydrogel softness.
Correct answer is: Electrical conductivity in the physiological range (µS–mS/cm)
Q.58 What does the term 'charge density' refer to in the context of neural stimulation?
Amount of charge per unit area
Amount of charge per unit volume
Total charge delivered over time
Charge per pulse
Explanation - Charge density is calculated as charge divided by electrode surface area; it determines safety limits for stimulation.
Correct answer is: Amount of charge per unit area
Q.59 Which of the following is NOT a typical feature of a 'biphasic' stimulation pulse?
Two opposite polarity phases
Net zero charge delivery
High amplitude
Equal phase durations
Explanation - Biphasic pulses are designed to cancel net charge; high amplitude would risk tissue damage regardless of phase polarity.
Correct answer is: High amplitude
Q.60 What is the purpose of adding carbon nanotubes to a collagen scaffold for neural tissue engineering?
To increase degradation rate
To enhance mechanical stiffness only
To provide electrical pathways that promote neurite outgrowth
To color the scaffold blue
Explanation - Carbon nanotubes improve conductivity and create micro‑tracks guiding nerve cell extension.
Correct answer is: To provide electrical pathways that promote neurite outgrowth
Q.61 Which of the following parameters is essential for avoiding electrode polarization in long‑term implants?
High impedance
Low charge per phase
High pulse frequency
Large electrode surface area
Explanation - A larger surface area reduces polarization by spreading charge over a broader area, maintaining stable potentials.
Correct answer is: Large electrode surface area
Q.62 Why are multi‑modal sensing capabilities (electrical + optical) valuable in tissue‑engineering devices?
To increase cost
To allow simultaneous monitoring of electrical activity and fluorescence markers
To avoid using electrodes
To simplify device architecture
Explanation - Combining modalities provides richer data on cell function and viability during tissue maturation.
Correct answer is: To allow simultaneous monitoring of electrical activity and fluorescence markers
Q.63 What is a common challenge when integrating high‑density electrode arrays into soft tissue constructs?
Poor electrical contact
Limited mechanical compliance
High manufacturing cost
Low optical transparency
Explanation - High‑density arrays can stiffen the construct, leading to mechanical mismatch and inflammation.
Correct answer is: Limited mechanical compliance
Q.64 Which electrical stimulation protocol is frequently used to promote myoblast differentiation in vitro?
Continuous low‑frequency AC
Pulsed DC at 2 V/cm, 20 Hz
High‑frequency AC at 1 kHz
No stimulation
Explanation - This protocol mimics the electrical activity of muscle cells, inducing myogenic differentiation.
Correct answer is: Pulsed DC at 2 V/cm, 20 Hz
Q.65 What is the primary advantage of using a 'floating' electrode configuration for bioelectronic implants?
Reduces foreign body response by allowing electrode movement with tissue
Increases power consumption
Simplifies wiring
Makes the device heavier
Explanation - Floating electrodes minimize mechanical stress at the interface, extending device lifespan.
Correct answer is: Reduces foreign body response by allowing electrode movement with tissue
Q.66 Which of the following best describes the term 'galvanotaxis'?
Cell movement guided by chemical gradients
Cell movement guided by magnetic fields
Cell movement guided by electrical fields
Cell movement guided by mechanical stiffness
Explanation - Galvanotaxis refers to directional cell migration induced by external electric fields.
Correct answer is: Cell movement guided by electrical fields
Q.67 What is the typical safe current density for chronic electrical stimulation of the peripheral nerve?
Below 0.1 mA/mm²
Between 0.1–0.3 mA/mm²
Between 0.3–1 mA/mm²
Above 1 mA/mm²
Explanation - Exceeding 0.3 mA/mm² increases the risk of nerve damage due to excessive heating and electrochemical reactions.
Correct answer is: Between 0.1–0.3 mA/mm²
Q.68 Why is impedance matching important in bioelectronic device design?
It increases signal noise
It maximizes power transfer and reduces reflection losses
It reduces device size
It increases the electrode surface area
Explanation - Matching the electrical impedance of the electrode to the tissue impedance ensures efficient signal acquisition and stimulation.
Correct answer is: It maximizes power transfer and reduces reflection losses
Q.69 What is the main function of a 'reference electrode' in a three‑terminal potentiostat?
To provide electrical contact with the device
To serve as a stable potential reference point
To measure impedance
To deliver current to the sample
Explanation - The reference electrode provides a known potential against which the working electrode’s potential is measured.
Correct answer is: To serve as a stable potential reference point
Q.70 Which of the following electrical characteristics is most relevant for a neural recording electrode?
High resistance
Low impedance
High capacitance
High noise floor
Explanation - Low‑impedance electrodes reduce thermal noise and improve signal quality in neural recordings.
Correct answer is: Low impedance
Q.71 What is the effect of a 1 µs pulse width in electroporation?
It creates large permanent pores
It is too short to permeabilize membranes
It induces transient pores suitable for DNA uptake
It causes irreversible cell death
Explanation - Microsecond pulses generate short‑duration pores that allow gene transfer while preserving cell viability.
Correct answer is: It induces transient pores suitable for DNA uptake
Q.72 Which type of electrode material is considered non‑conductive but useful for passive tissue scaffolds?
Gold
Silicon dioxide
PEDOT
Graphene
Explanation - SiO₂ is non‑conductive and provides a biocompatible substrate for tissue scaffolds, whereas the other options are conductive.
Correct answer is: Silicon dioxide
Q.73 What is the primary function of a 'bio‑resistor' in a tissue‑engineering circuit?
To store electrical charge
To regulate current flow through the scaffold
To generate heat
To provide optical signals
Explanation - A bio‑resistor limits current, ensuring safe levels for cell stimulation and protecting the device.
Correct answer is: To regulate current flow through the scaffold
Q.74 Which of the following is an advantage of using 'soft lithography' in electrode fabrication?
It allows high‑temperature processes
It produces rigid electrodes
It creates flexible micro‑electrodes that match tissue mechanics
It increases device cost
Explanation - Soft lithography uses elastomeric molds to pattern conductive inks on flexible substrates, improving conformability.
Correct answer is: It creates flexible micro‑electrodes that match tissue mechanics
Q.75 Which parameter is crucial for ensuring that an implanted electrode does not cause chronic inflammation?
High surface roughness
Biocompatible coating
High electrical resistance
Large electrode size
Explanation - Surface coatings such as PEG or poly‑ethylene glycol reduce protein adsorption and immune activation.
Correct answer is: Biocompatible coating
Q.76 What is the effect of applying a low‑intensity DC field on the differentiation of induced pluripotent stem cells (iPSCs)?
Promotes adipogenic differentiation
Promotes osteogenic differentiation via BMP signaling
Inhibits all differentiation
Causes iPSC apoptosis
Explanation - Low‑intensity DC fields can up‑regulate bone morphogenetic protein (BMP) pathways, steering iPSCs toward bone lineage.
Correct answer is: Promotes osteogenic differentiation via BMP signaling
Q.77 Which of the following is a typical safety limit for charge injection in neural stimulation?
10 mC/cm²
100 µC/cm²
1 mC/cm²
5 C/cm²
Explanation - Charge injection limits (~1 mC/cm²) prevent electrochemical damage to tissue and electrode degradation.
Correct answer is: 1 mC/cm²
Q.78 What is a common method to achieve uniform electrical field distribution in a microfluidic tissue‑engineering chip?
Using a single large electrode
Patterning multiple electrodes across the chip
Applying magnetic fields
Heating the chip uniformly
Explanation - Multiple electrode patterns create overlapping fields, ensuring even stimulation across the cell culture area.
Correct answer is: Patterning multiple electrodes across the chip
Q.79 Why is the 'water window' critical in designing electrodes for neural stimulation?
It determines the temperature tolerance
It defines the safe voltage window to avoid electrolysis
It limits the size of the electrodes
It sets the optical transparency
Explanation - Staying within the water window prevents gas formation and electrode corrosion, preserving tissue health.
Correct answer is: It defines the safe voltage window to avoid electrolysis
Q.80 Which of the following best describes the function of a 'shunt' in an implanted electrical device?
To amplify signals
To provide a low‑impedance pathway for excess charge
To store energy
To detect temperature changes
Explanation - A shunt electrode protects against over‑voltage by redirecting current safely away from sensitive tissue.
Correct answer is: To provide a low‑impedance pathway for excess charge
Q.81 What is the primary reason for using flexible polymers in neural electrode arrays?
To increase device cost
To match the mechanical properties of brain tissue
To prevent electrical conduction
To make the device heavy
Explanation - Flexible polymers reduce mechanical mismatch, lowering glial scar formation and improving signal longevity.
Correct answer is: To match the mechanical properties of brain tissue
Q.82 Which electrical stimulation protocol is most effective for promoting fibroblast proliferation in dermal wound healing?
High‑frequency (1 kHz) DC
Low‑frequency (10 Hz) biphasic pulses
Continuous AC at 50 Hz
No stimulation
Explanation - Low‑frequency biphasic stimulation enhances fibroblast proliferation and collagen deposition in healing skin.
Correct answer is: Low‑frequency (10 Hz) biphasic pulses
Q.83 What is the advantage of using a 'closed‑loop' stimulation system in neural prosthetics?
It simplifies device architecture
It automatically adjusts stimulation based on real‑time feedback
It uses more power
It requires no sensors
Explanation - Closed‑loop systems monitor neural activity and adapt stimulation, improving efficacy and safety.
Correct answer is: It automatically adjusts stimulation based on real‑time feedback
Q.84 Which of the following best explains the concept of 'electroactive hydrogels'?
Hydrogels that conduct electricity but do not change shape
Hydrogels that swell in response to electric fields
Hydrogels that conduct electricity and can change shape or release drugs upon stimulation
Hydrogels that are insulating
Explanation - Electroactive hydrogels combine conductivity with responsive behavior, useful for dynamic tissue scaffolds.
Correct answer is: Hydrogels that conduct electricity and can change shape or release drugs upon stimulation
Q.85 What is a typical application of 'magnetic nanoparticles' in tissue engineering?
To provide mechanical support only
To generate heat via inductive heating for controlled drug release
To prevent cell adhesion
To make the scaffold transparent
Explanation - Magnetically responsive nanoparticles can be heated remotely, triggering drug release or stimulating cells.
Correct answer is: To generate heat via inductive heating for controlled drug release
Q.86 Which parameter is NOT directly related to the design of a bioelectronic skin graft?
Electrical conductivity
Mechanical compliance
Thermal conductivity
Biodegradability
Explanation - While conductivity, compliance, and biodegradability affect device performance, thermal conductivity is less critical for skin grafts.
Correct answer is: Thermal conductivity
Q.87 Which of the following describes the 'charge‑balancing' requirement in biphasic stimulation?
Ensuring equal positive and negative charges per cycle
Providing a larger positive phase only
Using only negative pulses
Avoiding any charge injection
Explanation - Charge balancing prevents net charge buildup, reducing electrode corrosion and tissue damage.
Correct answer is: Ensuring equal positive and negative charges per cycle
Q.88 Why are 'tissue‑engineered' nerve grafts often combined with electrical stimulation?
To sterilize the graft
To reduce mechanical strength
To enhance axonal regeneration and functional recovery
To increase graft size
Explanation - Electrical cues promote growth cone advancement, accelerating nerve repair and restoring function.
Correct answer is: To enhance axonal regeneration and functional recovery
Q.89 What is the main purpose of 'electrospun' conductive fibers in cardiac tissue engineering?
To act as a nutrient source
To provide aligned electrical pathways that guide cardiomyocyte orientation
To increase scaffold rigidity
To reduce electrical conductivity
Explanation - Aligned conductive fibers mimic the heart’s anisotropic structure, encouraging synchronized beating.
Correct answer is: To provide aligned electrical pathways that guide cardiomyocyte orientation
Q.90 Which material property is essential for a conductive polymer used in neural recording electrodes?
High optical reflectivity
High electrical resistivity
High electrical conductivity and biocompatibility
Low chemical stability
Explanation - Conductive polymers must allow efficient signal transfer while being non‑toxic to neural tissue.
Correct answer is: High electrical conductivity and biocompatibility
Q.91 What is the most common method for delivering electrical stimulation to a 3‑D engineered bone construct?
Direct contact with a macro‑electrode
Embedding conductive fibers throughout the scaffold
Using magnetic resonance imaging
Applying static magnetic fields
Explanation - Distributed conductive elements provide uniform field distribution and mechanical support for bone tissue.
Correct answer is: Embedding conductive fibers throughout the scaffold
Q.92 Which of the following is a major challenge when using metallic electrodes in chronic implants?
They dissolve too quickly
They are too flexible
They can corrode and release ions over time
They cannot be sterilized
Explanation - Metallic electrodes may corrode, releasing ions that can cause inflammation or tissue damage.
Correct answer is: They can corrode and release ions over time
Q.93 What is the typical electrical conductivity range for a biocompatible hydrogel used in cardiac patches?
10⁻⁴ to 10⁻⁶ S/m
10⁻² to 10⁰ S/m
10⁰ to 10² S/m
10³ to 10⁵ S/m
Explanation - Conductivities of 10⁻² to 10⁰ S/m mimic physiological ranges, allowing effective electrical coupling.
Correct answer is: 10⁻² to 10⁰ S/m
Q.94 Which of the following best describes 'electro‑osmosis'?
Movement of ions across a membrane
Flow of liquid induced by an electric field through a porous medium
Generation of heat in an electrolyte
Chemical reaction at electrode surface
Explanation - Electro‑osmosis drives fluid motion in microfluidic devices, enhancing mass transport for tissue constructs.
Correct answer is: Flow of liquid induced by an electric field through a porous medium
Q.95 What is the role of 'micro‑LEDs' integrated into tissue‑engineering scaffolds?
To provide illumination for imaging
To stimulate cells via optogenetics
To generate heat for drug release
To act as mechanical support
Explanation - Micro‑LEDs can deliver light to activate genetically encoded ion channels, enabling precise control of cell activity.
Correct answer is: To stimulate cells via optogenetics
Q.96 Which electrical property is crucial for ensuring that a bioelectronic device does not interfere with cardiac pacemaking?
High impedance
Low noise floor
High power consumption
Large physical size
Explanation - High‑impedance interfaces minimize current injection, reducing the risk of unwanted cardiac pacing or arrhythmias.
Correct answer is: High impedance
Q.97 What is the main advantage of using a 'soft, porous' electrode for bone regeneration?
It blocks cell infiltration
It improves mechanical strength only
It allows vascular infiltration and cell migration while providing conductivity
It is non‑biodegradable
Explanation - Porosity promotes tissue ingrowth, and softness reduces foreign body response.
Correct answer is: It allows vascular infiltration and cell migration while providing conductivity
Q.98 Which type of stimulation is commonly used in spinal cord injury to promote axon regeneration?
High‑frequency AC
Low‑frequency pulsed DC
Continuous DC
Random noise
Explanation - Low‑frequency pulsed DC stimulates axonal growth and functional recovery while limiting tissue damage.
Correct answer is: Low‑frequency pulsed DC
Q.99 What is the purpose of a 'galvanic coupling' in a bio‑sensor array?
To transmit power wirelessly
To couple electrical signals between two electrodes via an electrolyte
To reduce impedance
To sterilize the device
Explanation - Galvanic coupling transfers signals across a conductive medium, enabling remote sensing.
Correct answer is: To couple electrical signals between two electrodes via an electrolyte
Q.100 Which of the following best explains why 'ion‑tunable' hydrogels are useful in dynamic tissue scaffolds?
They can change color
They allow reversible tuning of electrical conductivity via ion concentration
They are non‑conductive
They dissolve immediately
Explanation - Changing ion content modulates hydrogel conductivity, enabling on‑demand stimulation adjustments.
Correct answer is: They allow reversible tuning of electrical conductivity via ion concentration
Q.101 Which of the following is a key consideration when selecting an electrode material for retinal implants?
High magnetic susceptibility
High electrical conductivity and biocompatibility
Low optical transparency
High brittleness
Explanation - Retinal electrodes must conduct signals efficiently while remaining safe for ocular tissues.
Correct answer is: High electrical conductivity and biocompatibility
Q.102 Which parameter is most important for ensuring safe chronic stimulation of the spinal cord?
Pulse width
Amplitude
Total charge delivered per phase
Number of electrodes
Explanation - Limiting the charge per phase protects the spinal tissue from electrochemical damage.
Correct answer is: Total charge delivered per phase
Q.103 What is the role of 'polyimide' in flexible neural electrodes?
To act as a stiff support
To serve as a biocompatible, flexible substrate
To provide electrical insulation only
To degrade quickly in body fluids
Explanation - Polyimide offers flexibility, mechanical stability, and chemical resistance for implanted neural arrays.
Correct answer is: To serve as a biocompatible, flexible substrate
Q.104 Which of the following best describes the function of a 'transparent electrode' in optogenetics?
To block light
To allow optical illumination while recording electrical activity
To increase electrode size
To generate heat
Explanation - Transparent electrodes (e.g., ITO) permit light to pass through, enabling simultaneous optogenetic stimulation and electrophysiology.
Correct answer is: To allow optical illumination while recording electrical activity
Q.105 Which factor is least important for ensuring the long‑term stability of a bioelectronic implant?
Mechanical durability
Electrical impedance stability
Surface roughness
Device weight
Explanation - Weight has minimal impact on implant stability compared to material properties and impedance.
Correct answer is: Device weight
Q.106 What is a primary application of 'magnetoelectric' materials in bone tissue engineering?
To generate heat for hyperthermia
To convert magnetic fields into electrical potentials that stimulate bone cells
To provide optical contrast
To degrade the scaffold rapidly
Explanation - Magnetoelectric materials generate local electrical signals when exposed to external magnetic fields, promoting osteogenesis.
Correct answer is: To convert magnetic fields into electrical potentials that stimulate bone cells
Q.107 What is the purpose of a 'galvanic electrode' in a cardiac pacing system?
To provide mechanical support
To deliver electrical pulses directly to heart tissue
To generate heat
To provide optical imaging
Explanation - The galvanic electrode acts as the active site for delivering pacing currents to the myocardium.
Correct answer is: To deliver electrical pulses directly to heart tissue
Q.108 Which of the following is a characteristic of a 'high‑fidelity' neural recording system?
High thermal noise
Low impedance and low noise floor
High power consumption
Large electrode size
Explanation - Low impedance minimizes thermal noise and improves signal‑to‑noise ratio, essential for accurate neural recordings.
Correct answer is: Low impedance and low noise floor
Q.109 Which electrical property is crucial for designing a biocompatible electrode that promotes osteogenic differentiation?
High optical absorbance
Low electrical resistivity
High magnetic susceptibility
High thermal conductivity
Explanation - Low resistivity ensures efficient current delivery, stimulating osteogenic pathways in bone cells.
Correct answer is: Low electrical resistivity
Q.110 What is the primary advantage of 'electroactive' biomaterials in tissue scaffolds?
They are non‑conductive
They can change their shape or release drugs in response to electrical stimuli
They provide no electrical cues
They are hard to process
Explanation - Electroactive materials respond to electrical fields, offering dynamic control over scaffold behavior.
Correct answer is: They can change their shape or release drugs in response to electrical stimuli