Q.1 What is the primary purpose of using scaffolds in tissue engineering?
To deliver drugs to target cells
To provide structural support for cell growth
To generate electrical signals
To analyze genetic mutations
Explanation - Scaffolds mimic the extracellular matrix, offering a three‑dimensional structure that supports cell adhesion, proliferation, and differentiation.
Correct answer is: To provide structural support for cell growth
Q.2 Which cell type is commonly used for autologous skin grafts in regenerative medicine?
Mesenchymal stem cells
Keratinocytes
Hepatocytes
Neutrophils
Explanation - Keratinocytes are the main cells of the epidermis and are harvested from the patient’s skin for autologous grafts.
Correct answer is: Keratinocytes
Q.3 What is a key advantage of using bioreactors in cell‑based therapies?
They reduce the need for antibiotics
They enable large‑scale, controlled cell culture
They eliminate the need for scaffolds
They automatically differentiate cells into any lineage
Explanation - Bioreactors provide controlled environments (oxygen, nutrients, shear) for expanding therapeutic cells at scale.
Correct answer is: They enable large‑scale, controlled cell culture
Q.4 Which of the following is NOT a typical component of a tissue engineering construct?
Growth factors
Scaffold material
Genetic material
Electrical wiring
Explanation - While electrical stimulation can be applied, actual wiring is not a typical component of the construct itself.
Correct answer is: Electrical wiring
Q.5 In the context of CAR‑T cell therapy, what does CAR stand for?
Cytokine‑Activating Receptor
Chimeric Antigen Receptor
Cellular Antigen Receptor
Chronic Antibody Response
Explanation - CAR‑T cells are engineered to express a chimeric antigen receptor that recognizes tumor‑specific antigens.
Correct answer is: Chimeric Antigen Receptor
Q.6 Which technique is commonly used to assess the viability of cultured cells before implantation?
Western blotting
Live/dead staining with calcein AM and propidium iodide
PCR for housekeeping genes
Mass spectrometry of extracellular vesicles
Explanation - Live/dead staining allows rapid visualization of live (green) and dead (red) cells in culture.
Correct answer is: Live/dead staining with calcein AM and propidium iodide
Q.7 Which material is often chosen for its biodegradability and similarity to native cartilage ECM?
Polylactic acid (PLA)
Polyethylene glycol (PEG)
Polycaprolactone (PCL)
Collagen type I
Explanation - Collagen I is a natural ECM protein that degrades over time and supports cartilage tissue formation.
Correct answer is: Collagen type I
Q.8 What is the main regulatory challenge for cell‑based medicinal products in the EU?
Lack of defined classification in the GMP guidelines
High cost of raw materials
Unclear patent law for genetically modified cells
Absence of a unified clinical trial design
Explanation - The EU has specific GMP requirements, but the classification of advanced therapy medicinal products (ATMPs) can be ambiguous.
Correct answer is: Lack of defined classification in the GMP guidelines
Q.9 What is the purpose of a bioreactor's perfusion system in tissue engineering?
To sterilize the scaffold
To provide mechanical stimulation
To supply nutrients and remove waste continuously
To freeze the construct for storage
Explanation - Perfusion delivers media through the scaffold, enhancing nutrient transport and waste removal, mimicking vascular flow.
Correct answer is: To supply nutrients and remove waste continuously
Q.10 Which cell surface marker is commonly used to identify mesenchymal stem cells?
CD34
CD45
CD73
CD19
Explanation - CD73 (5′‑nucleotidase) is one of several markers (CD73, CD90, CD105) used to characterize MSCs.
Correct answer is: CD73
Q.11 The process of inducing pluripotent stem cells from somatic cells is known as:
Differentiation
Reprogramming
Transdifferentiation
Apoptosis
Explanation - Reprogramming converts differentiated cells back to a pluripotent state, typically using Yamanaka factors.
Correct answer is: Reprogramming
Q.12 Which of the following best describes a 3D bioprinter's nozzle?
A laser that cross‑links polymers
An extrusion head that deposits cell‑laden bioinks
A microfluidic channel for nutrient delivery
A sensor array detecting scaffold porosity
Explanation - 3D bioprinters use extrusion nozzles to print layers of bioink containing living cells.
Correct answer is: An extrusion head that deposits cell‑laden bioinks
Q.13 Why is oxygen tension controlled during stem cell differentiation?
To prevent bacterial contamination
To maintain the temperature
To influence lineage commitment
To adjust the pH of the media
Explanation - Hypoxic or normoxic conditions can steer differentiation toward specific cell types (e.g., osteogenesis in low O2).
Correct answer is: To influence lineage commitment
Q.14 Which scaffold fabrication technique allows for precise control over pore size distribution?
Freeze‑casting
Electrospinning
Stereolithography
3D printing (additive manufacturing)
Explanation - 3D printing can build scaffolds layer‑by‑layer with designed pore architectures.
Correct answer is: 3D printing (additive manufacturing)
Q.15 What is the main function of the extracellular matrix in engineered tissues?
To provide electrical conductivity
To supply genetic material
To offer mechanical support and biochemical cues
To eliminate immune responses
Explanation - ECM provides both structural integrity and signals (growth factors) that guide cell behavior.
Correct answer is: To offer mechanical support and biochemical cues
Q.16 In which type of bioreactor is shear stress deliberately applied to promote cell maturation?
Static culture
Spinner flask
Perfusion bioreactor
Rotating wall vessel
Explanation - The rotating wall vessel generates low‑shear, microgravity‑like conditions conducive to differentiation.
Correct answer is: Rotating wall vessel
Q.17 Which imaging technique is best suited for non‑invasive monitoring of tissue growth inside a scaffold?
Confocal microscopy
Computed tomography (CT)
Magnetic resonance imaging (MRI)
X‑ray diffraction
Explanation - MRI can image soft tissues and scaffold integration without damaging the construct.
Correct answer is: Magnetic resonance imaging (MRI)
Q.18 What is the primary advantage of using induced pluripotent stem cells (iPSCs) over embryonic stem cells in therapy?
They are more differentiated
They are less expensive to produce
They avoid ethical concerns and immune rejection
They require less growth factor supplementation
Explanation - iPSCs are derived from adult cells, reducing ethical issues and allowing patient‑specific therapies.
Correct answer is: They avoid ethical concerns and immune rejection
Q.19 Which signaling pathway is critical for maintaining stem cell pluripotency?
Wnt/β‑catenin
MAPK/ERK
PI3K/Akt
Notch
Explanation - Wnt signaling is key for self‑renewal and pluripotency in embryonic stem cells.
Correct answer is: Wnt/β‑catenin
Q.20 Which type of growth factor is most commonly used to promote angiogenesis in tissue‑engineered constructs?
VEGF
TGF‑β
BMP-2
IGF‑1
Explanation - Vascular endothelial growth factor (VEGF) drives the formation of new blood vessels within engineered tissues.
Correct answer is: VEGF
Q.21 What is the role of decellularized extracellular matrix (dECM) in regenerative medicine?
To act as a scaffold with native biochemical cues
To provide a source of DNA for gene editing
To function as a drug delivery device
To replace damaged organs permanently
Explanation - dECM retains the composition of native tissues, guiding cell behavior without immunogenicity.
Correct answer is: To act as a scaffold with native biochemical cues
Q.22 Which of the following is NOT a common method for measuring scaffold porosity?
Mercury intrusion porosimetry
Scanning electron microscopy (SEM)
Micro‑CT imaging
Dynamic light scattering (DLS)
Explanation - DLS is used for nanoparticles in suspension, not for macro‑scale scaffold porosity.
Correct answer is: Dynamic light scattering (DLS)
Q.23 In the context of tissue engineering, what does the term 'biocompatibility' refer to?
The ability to conduct electricity
The material’s resistance to corrosion
The lack of toxic or immunogenic response in the body
The capacity to be processed by a bioreactor
Explanation - Biocompatible materials do not elicit harmful immune reactions when implanted.
Correct answer is: The lack of toxic or immunogenic response in the body
Q.24 What distinguishes a ‘cell‑based therapy’ from a ‘gene‑based therapy’?
Cell‑based therapy uses drugs, gene‑based therapy uses viruses
Cell‑based therapy delivers live cells, gene‑based therapy delivers genetic material
Cell‑based therapy is always autologous, gene‑based therapy is always allogenic
Cell‑based therapy cannot be regulated, gene‑based therapy can
Explanation - Cell therapies introduce living cells; gene therapies introduce or modify genes.
Correct answer is: Cell‑based therapy delivers live cells, gene‑based therapy delivers genetic material
Q.25 Which of the following is a common source of MSCs for cartilage repair?
Bone marrow
Spleen
Liver
Adipose tissue
Explanation - Adipose‑derived MSCs are abundant, easy to harvest, and effective for cartilage regeneration.
Correct answer is: Adipose tissue
Q.26 What is the function of a 'spheroid' in stem cell culture?
To mimic a tumor
To provide a 3D microenvironment for differentiation
To act as a bioreactor
To be a source of extracellular vesicles
Explanation - Spheroids simulate a 3D niche, improving differentiation efficiency compared to 2D monolayers.
Correct answer is: To provide a 3D microenvironment for differentiation
Q.27 Which device is commonly used to apply controlled electrical stimulation to engineered tissues?
Electrospinning machine
Cytometer
Electrical pulse stimulator
Thermal cycler
Explanation - Pulse stimulators deliver precise electrical signals to enhance tissue maturation, e.g., muscle or nerve tissue.
Correct answer is: Electrical pulse stimulator
Q.28 Which scaffold material is known for its high tensile strength and suitability for tendon repair?
Poly(lactic-co-glycolic acid) (PLGA)
Polycaprolactone (PCL)
Silk fibroin
Alginate
Explanation - Silk fibroin offers excellent mechanical strength and biocompatibility, ideal for tendon applications.
Correct answer is: Silk fibroin
Q.29 What is the primary concern when using viral vectors for gene delivery in cell therapies?
Low transfection efficiency
Immunogenicity and insertional mutagenesis
High cost of viral production
Limited cargo capacity
Explanation - Viral vectors can trigger immune responses and randomly integrate into host DNA, posing safety risks.
Correct answer is: Immunogenicity and insertional mutagenesis
Q.30 Which technique allows for the selective removal of cellular components while preserving the ECM structure?
Centrifugation
Decellularization
Cryopreservation
Electroporation
Explanation - Decellularization removes cells, leaving behind the ECM scaffold for regenerative applications.
Correct answer is: Decellularization
Q.31 Which parameter is most critical to control when scaling up bioreactor cultures for therapeutic cell production?
Temperature
pH
Oxygen transfer rate (OTR)
Light intensity
Explanation - Adequate OTR ensures sufficient oxygen for high‑density cultures and prevents hypoxia‑induced apoptosis.
Correct answer is: Oxygen transfer rate (OTR)
Q.32 In a scaffold designed for bone regeneration, why is the incorporation of hydroxyapatite (HA) beneficial?
It enhances electrical conductivity
It mimics bone mineral composition and promotes osteointegration
It provides antibacterial properties
It increases scaffold porosity dramatically
Explanation - HA is similar to the mineral phase of bone, improving bone bonding and cell attachment.
Correct answer is: It mimics bone mineral composition and promotes osteointegration
Q.33 Which of the following is a typical outcome measure for evaluating engineered skin in vivo?
Blood glucose level
Epidermal thickness and barrier function
Lung compliance
Cardiac output
Explanation - Engineered skin is assessed by its structural thickness and barrier properties such as transepidermal water loss.
Correct answer is: Epidermal thickness and barrier function
Q.34 What is a key advantage of using microfluidic platforms in tissue‑engineered organoids?
They reduce the need for oxygen
They allow precise control of nutrient gradients
They enable large‑scale production
They eliminate the requirement for scaffolds
Explanation - Microfluidic channels can deliver spatially varying conditions, mimicking organ microenvironments.
Correct answer is: They allow precise control of nutrient gradients
Q.35 Which biomarker is commonly used to confirm the differentiation of induced pluripotent stem cells into cardiomyocytes?
GATA4
Oct4
Sox2
Nestin
Explanation - GATA4 is a transcription factor essential for cardiac lineage differentiation.
Correct answer is: GATA4
Q.36 What is the main purpose of using a 'bioreactor‑integrated sensor' in cell culture?
To sterilize the culture medium
To provide real‑time monitoring of culture parameters
To harvest cells automatically
To enhance scaffold stiffness
Explanation - Sensors detect pH, oxygen, glucose, enabling precise control and early detection of culture deviations.
Correct answer is: To provide real‑time monitoring of culture parameters
Q.37 Which of the following is NOT a characteristic of a Good Manufacturing Practice (GMP) compliant cell culture facility?
Controlled environmental conditions
Traceability of all materials
Open bench access for all personnel
Validated cleaning procedures
Explanation - GMP requires restricted access to maintain sterile, controlled environments.
Correct answer is: Open bench access for all personnel
Q.38 Which type of stem cell therapy is most suitable for treating acute spinal cord injury?
Autologous adipose MSCs
Allogeneic iPSC‑derived neural progenitors
Hematopoietic stem cells
Dental pulp stem cells
Explanation - Neural progenitors derived from iPSCs can differentiate into neurons and glia, aiding spinal cord repair.
Correct answer is: Allogeneic iPSC‑derived neural progenitors
Q.39 Why are 'bioprinting' approaches preferred for complex organoid fabrication?
They are cheaper than static culture
They allow precise placement of multiple cell types in 3D
They eliminate the need for growth factors
They increase cell proliferation rates
Explanation - Bioprinting can deposit distinct cell populations in defined architectures, replicating organ complexity.
Correct answer is: They allow precise placement of multiple cell types in 3D
Q.40 Which assay is most suitable for assessing the mechanical strength of a scaffold before implantation?
Tensile test
ELISA
MTT assay
Flow cytometry
Explanation - Tensile testing measures the load‑to‑failure, giving the scaffold’s mechanical strength.
Correct answer is: Tensile test
Q.41 What is a key challenge in translating in‑vitro engineered tissues to clinical applications?
Availability of bioreactors
High cost of growth media
Ensuring vascular integration and nutrient delivery
Lack of funding
Explanation - Without vascularization, implanted tissues suffer from hypoxia and cell death.
Correct answer is: Ensuring vascular integration and nutrient delivery
Q.42 Which of the following best describes 'cell‑laden bioink' used in 3D bioprinting?
A hydrogel with embedded living cells
A polymer that dissolves in water
A cross‑linking chemical only
A non‑biological resin
Explanation - Cell‑laden bioink is a printable hydrogel that contains viable cells for tissue fabrication.
Correct answer is: A hydrogel with embedded living cells
Q.43 In the context of regenerative medicine, what does the acronym 'ATMP' stand for?
Advanced Therapeutic Medical Protocol
Advanced Therapy Medicinal Product
Acellular Tissue Matrix Product
Antibody‑Targeted Medical Program
Explanation - ATMP refers to cell‑based, gene‑based, or tissue‑engineered therapies regulated by the EU.
Correct answer is: Advanced Therapy Medicinal Product
Q.44 Which parameter is most critical for ensuring uniform cell seeding in a porous scaffold?
Scaffold thickness
Pore size distribution
Media temperature
Light exposure
Explanation - Appropriate pore sizes allow cells to infiltrate evenly throughout the scaffold.
Correct answer is: Pore size distribution
Q.45 Which cell signaling pathway is often targeted to enhance osteogenic differentiation of MSCs?
Wnt/β‑catenin
NF‑κB
JAK/STAT
MAPK/ERK
Explanation - Activation of Wnt signaling promotes bone formation from MSCs.
Correct answer is: Wnt/β‑catenin
Q.46 Why are hydrogels commonly used as bioinks in bioprinting?
They are electrically conductive
They provide a soft, cell‑friendly environment
They are rigid and stable
They are made of synthetic polymers only
Explanation - Hydrogels mimic natural ECM, supporting cell viability and proliferation.
Correct answer is: They provide a soft, cell‑friendly environment
Q.47 Which of the following is NOT an advantage of using allogeneic MSCs?
Immediate availability
Reduced immunogenicity
Higher potency than autologous MSCs
Potential for batch standardization
Explanation - Allogeneic MSCs may show similar potency but are not inherently more potent than autologous cells.
Correct answer is: Higher potency than autologous MSCs
Q.48 What is the purpose of using a 'mimetic' growth factor release system in scaffolds?
To degrade the scaffold faster
To provide a sustained, spatially controlled release of growth factors
To increase scaffold porosity
To make the scaffold magnetic
Explanation - Controlled release mimics natural signaling patterns, improving tissue regeneration.
Correct answer is: To provide a sustained, spatially controlled release of growth factors
Q.49 Which imaging modality is best for real‑time monitoring of cell migration within a scaffold?
Computed tomography (CT)
Bioluminescence imaging (BLI)
Magnetic resonance imaging (MRI)
Ultrasound
Explanation - BLI can track luciferase‑expressing cells in living organisms non‑invasively.
Correct answer is: Bioluminescence imaging (BLI)
Q.50 Which of the following best describes an 'organ‑on‑a‑chip' platform?
A miniature organ fabricated from plastic
A microfluidic device that mimics organ physiology
A 3D printed whole organ for implantation
A device for storing organ tissue samples
Explanation - Organ‑on‑a‑chip integrates cells and microfluidics to replicate organ-level functions in vitro.
Correct answer is: A microfluidic device that mimics organ physiology
Q.51 In cell therapy, what is a 'differentiation bottleneck'?
A point where cells cannot survive due to low oxygen
A stage where differentiation efficiency drops drastically
A regulatory hurdle for clinical trials
A mechanical limitation of bioreactors
Explanation - A differentiation bottleneck refers to a developmental stage where cells fail to progress, limiting yield.
Correct answer is: A stage where differentiation efficiency drops drastically
Q.52 Which polymer is most commonly used as a biodegradable scaffold for soft tissue engineering?
Poly(lactic acid) (PLA)
Polyethylene glycol (PEG)
Polycaprolactone (PCL)
Polylactic-co-glycolic acid (PLGA)
Explanation - PEG hydrogels are highly biocompatible, hydrophilic, and degrade into non‑toxic products.
Correct answer is: Polyethylene glycol (PEG)
Q.53 Which cell type is most relevant for studying immunomodulatory effects in tissue‑engineered constructs?
Neuronal cells
Macrophages
Cardiomyocytes
Osteoblasts
Explanation - Macrophages interact with scaffolds and influence inflammation, a key factor in tissue integration.
Correct answer is: Macrophages
Q.54 What role does the 'Notch signaling pathway' play in tissue engineering?
It promotes osteogenic differentiation of MSCs
It controls cell fate decisions during differentiation
It induces apoptosis in engineered tissues
It regulates scaffold degradation rate
Explanation - Notch signaling influences lineage commitment of progenitor cells within engineered constructs.
Correct answer is: It controls cell fate decisions during differentiation
Q.55 Which of the following is NOT a typical feature of a hydrogel scaffold?
High water content
Permeability to nutrients
Rigid mechanical strength
Biodegradability
Explanation - Hydrogels are generally soft and compliant, not rigid.
Correct answer is: Rigid mechanical strength
Q.56 Which assay is used to quantify DNA content as a surrogate for cell number in tissue constructs?
DAPI staining
DNA microarray
Picogreen assay
RNA‑seq
Explanation - Picogreen provides a sensitive fluorescent measurement of double‑stranded DNA.
Correct answer is: Picogreen assay
Q.57 What does the term 'cell‑seeding density' refer to?
Number of cells per scaffold volume
Total number of cells in the bioreactor
Density of the scaffold material
Concentration of growth factors
Explanation - Cell‑seeding density defines how many cells are initially placed within a scaffold per unit volume.
Correct answer is: Number of cells per scaffold volume
Q.58 Which type of analysis is essential for determining the differentiation status of stem cells post‑culture?
PCR for lineage‑specific markers
Blood pressure measurement
Calcium imaging of bone tissue
Surface temperature mapping
Explanation - Gene expression of lineage markers confirms successful differentiation.
Correct answer is: PCR for lineage‑specific markers
Q.59 What is the primary purpose of using a 'gel‑like' extracellular matrix in engineered tissues?
To increase scaffold stiffness
To provide a 3D environment for cells
To act as an electrical conductor
To inhibit cell migration
Explanation - Gel‑like matrices emulate the natural soft environment cells experience in vivo.
Correct answer is: To provide a 3D environment for cells
Q.60 Which cell line is commonly used as a model for hepatocyte function in tissue engineering?
HeLa
HepG2
MCF‑7
Jurkat
Explanation - HepG2 is a human liver carcinoma cell line that retains many hepatocyte functions.
Correct answer is: HepG2
Q.61 What is a key advantage of using induced pluripotent stem cells (iPSCs) for personalized medicine?
They can differentiate into any cell type without risk
They eliminate the need for immunosuppressants
They are derived from the patient, reducing rejection
They are cheaper to produce than MSCs
Explanation - iPSCs can be autologous, thereby minimizing immune rejection in therapy.
Correct answer is: They are derived from the patient, reducing rejection
Q.62 Which technique can be used to functionalize scaffold surfaces with adhesion peptides?
Electrospinning
Chemical cross‑linking with EDC/NHS
High‑temperature curing
Laser ablation
Explanation - EDC/NHS chemistry attaches peptides like RGD to scaffold surfaces to enhance cell adhesion.
Correct answer is: Chemical cross‑linking with EDC/NHS
Q.63 In bioreactors, what is the significance of 'mixing time'?
Time taken to fill the vessel
Duration required for homogeneous distribution of nutrients
Time for cells to adhere to the scaffold
Interval between media changes
Explanation - Mixing time ensures even distribution of oxygen, nutrients, and cells within the culture.
Correct answer is: Duration required for homogeneous distribution of nutrients
Q.64 Which of the following is a typical outcome of applying cyclic mechanical stretch to engineered muscle tissue?
Reduced cell viability
Enhanced myogenic differentiation and alignment
Increased scaffold degradation
Inhibition of protein synthesis
Explanation - Mechanical cues mimic natural muscle loading, promoting maturation and alignment.
Correct answer is: Enhanced myogenic differentiation and alignment
Q.65 Which scaffold material is known for its antibacterial properties due to silver ion release?
Polyurethane
Poly(lactic acid) (PLA)
Polycaprolactone (PCL) with silver nanoparticles
Silk fibroin
Explanation - Silver ions from incorporated nanoparticles provide sustained antibacterial activity.
Correct answer is: Polycaprolactone (PCL) with silver nanoparticles
Q.66 Which of the following best describes the 'Matrigel' used in cell culture?
A synthetic polymer scaffold
A natural basement membrane extract rich in ECM proteins
A bacterial growth medium
A chemical cross‑linker
Explanation - Matrigel mimics the basement membrane, supporting stem cell differentiation.
Correct answer is: A natural basement membrane extract rich in ECM proteins
Q.67 What is the main challenge in scaling up cell therapies from the bench to bedside?
Ensuring sufficient cell numbers while maintaining potency
Finding suitable bioreactors
Reducing the cost of scaffolds
Obtaining patient consent
Explanation - Large‑scale production must preserve cell function and phenotype.
Correct answer is: Ensuring sufficient cell numbers while maintaining potency
Q.68 Which of the following is NOT a standard quality attribute assessed for ATMPs?
Sterility
Potency
Stability
Color
Explanation - Color is not a critical quality attribute for cell‑based medicinal products.
Correct answer is: Color
Q.69 What is the purpose of adding 'serum‑free media' in therapeutic cell culture?
To reduce contamination risk
To enhance cell proliferation
To enable clinical compliance and reproducibility
All of the above
Explanation - Serum‑free conditions improve safety, consistency, and regulatory compliance.
Correct answer is: All of the above
Q.70 Which biomaterial is known for its shape‑memory properties useful in dynamic scaffolds?
Hydroxyapatite
Polyethylene glycol
Shape‑memory polymer (e.g., poly(glycolide‑trimethylene carbonate))
Collagen
Explanation - Shape‑memory polymers can change shape in response to stimuli, allowing dynamic scaffold behavior.
Correct answer is: Shape‑memory polymer (e.g., poly(glycolide‑trimethylene carbonate))
Q.71 Which technique is used to monitor cell viability in real time without disrupting the culture?
Fluorescence microscopy
Optical coherence tomography (OCT)
Electron microscopy
Mass spectrometry
Explanation - OCT provides non‑invasive, high‑resolution imaging of live tissues and cells.
Correct answer is: Optical coherence tomography (OCT)
Q.72 What is the primary function of 'hypoxia‑inducible factor 1 alpha (HIF‑1α)' in tissue engineering?
It promotes angiogenesis under low oxygen
It inhibits cell proliferation
It degrades the scaffold
It stimulates immune cells
Explanation - HIF‑1α activates VEGF expression, enhancing vascularization in hypoxic environments.
Correct answer is: It promotes angiogenesis under low oxygen
Q.73 Which type of cell therapy involves delivering cells that secrete therapeutic factors rather than replacing damaged tissue?
Cell replacement therapy
Paracrine therapy
Immunotherapy
Gene editing therapy
Explanation - Paracrine therapy relies on cell‑derived secretomes to mediate repair.
Correct answer is: Paracrine therapy
Q.74 Why is the use of 'xeno‑free' components important in clinical cell manufacturing?
To reduce cost
To avoid cross‑species contamination and immune reactions
To increase cell growth rate
To simplify the protocol
Explanation - Xeno‑free media eliminates animal‑derived components, enhancing safety.
Correct answer is: To avoid cross‑species contamination and immune reactions
Q.75 Which of the following is a key characteristic of a 'self‑assembling peptide' scaffold?
It requires high temperature to form
It spontaneously forms nanofibers in aqueous solution
It is electrically conductive
It degrades within 24 hours
Explanation - Self‑assembling peptides can form fibrillar networks without external stimuli.
Correct answer is: It spontaneously forms nanofibers in aqueous solution
Q.76 Which of the following assays is used to detect the presence of endotoxins in cell culture products?
Lactate dehydrogenase (LDH) assay
Limulus amebocyte lysate (LAL) assay
MTT assay
ELISA for cytokines
Explanation - LAL is the gold standard for detecting bacterial endotoxins.
Correct answer is: Limulus amebocyte lysate (LAL) assay
Q.77 Which factor is most critical when designing a scaffold for neural tissue engineering?
Electrical conductivity
High mechanical stiffness
High porosity
Low surface roughness
Explanation - Neural tissues respond to electrical cues; conductive scaffolds can enhance neuronal growth.
Correct answer is: Electrical conductivity
Q.78 What is the main benefit of 'gradient scaffolds' in regenerative medicine?
Uniform cell distribution
Spatial variation in material properties and cell types
Simplified manufacturing
Reduced cost
Explanation - Gradient scaffolds mimic tissue interfaces, guiding differentiation and integration.
Correct answer is: Spatial variation in material properties and cell types
Q.79 Which of the following is a typical method for sterilizing 3D printed biocompatible scaffolds?
Gamma irradiation
High‑temperature autoclaving
UV irradiation
All of the above
Explanation - Different sterilization methods are applied depending on material sensitivity.
Correct answer is: All of the above
Q.80 Which cell lineage marker is used to confirm osteogenic differentiation of MSCs?
Collagen type II
Osteocalcin (OCN)
Nestin
Aquaporin‑4
Explanation - OCN is a late marker of bone formation and indicates osteogenic commitment.
Correct answer is: Osteocalcin (OCN)
Q.81 What is the role of 'matrix metalloproteinases (MMPs)' in tissue engineering?
They provide structural integrity
They remodel the extracellular matrix
They act as growth factors
They inhibit cell differentiation
Explanation - MMPs degrade ECM components, enabling cell migration and scaffold remodeling.
Correct answer is: They remodel the extracellular matrix
Q.82 Which technique is commonly employed to enhance the mechanical strength of hydrogel scaffolds?
Cross‑linking with glutaraldehyde
Adding nanocellulose fibers
UV irradiation alone
High‑speed stirring
Explanation - Incorporating nanocellulose improves mechanical properties while preserving biocompatibility.
Correct answer is: Adding nanocellulose fibers
Q.83 What is a typical criterion for evaluating cell differentiation in a 3D culture?
Cell diameter measurement
Expression of lineage‑specific surface markers via flow cytometry
Ambient temperature
pH of the medium
Explanation - Flow cytometry quantitatively assesses differentiation markers in 3D‑grown cells.
Correct answer is: Expression of lineage‑specific surface markers via flow cytometry
Q.84 Which of the following is NOT a component of the standard GMP guidelines for cell therapies?
Sterility testing
Batch traceability
Patient‑specific labeling
Environmental monitoring
Explanation - Patient labeling is part of quality control but not a standalone GMP requirement.
Correct answer is: Patient‑specific labeling
Q.85 In an organoid model, what is the significance of a 'core‑shell' architecture?
It mimics the vascular core of organs
It ensures even cell distribution
It allows gradient of nutrients
All of the above
Explanation - A core‑shell design can replicate tissue architecture, nutrient gradients, and vascularization.
Correct answer is: All of the above
Q.86 Which of the following materials is widely used as a conductive polymer for cardiac tissue engineering?
Poly(3,4‑ethylenedioxythiophene) (PEDOT)
Polylactic acid (PLA)
Chitosan
Polycaprolactone (PCL)
Explanation - PEDOT provides electrical conductivity conducive to cardiac tissue function.
Correct answer is: Poly(3,4‑ethylenedioxythiophene) (PEDOT)
Q.87 Which of the following best describes the term 'bioprinting resolution'?
The speed of printing
The smallest feature size that can be accurately fabricated
The number of cell types that can be printed
The cost per printed scaffold
Explanation - Resolution determines how fine the printed structures can be, affecting cell distribution.
Correct answer is: The smallest feature size that can be accurately fabricated
Q.88 What is the main benefit of using a 'hydrogel‑based microcarrier' in suspension bioreactor cultures?
Increases oxygen diffusion
Reduces shear stress on cells
Facilitates cell aggregation and expansion
All of the above
Explanation - Hydrogel microcarriers provide a 3D niche, improve mass transfer, and reduce shear damage.
Correct answer is: All of the above
Q.89 Which of the following is a key consideration for the long‑term storage of engineered tissues?
Cryopreservation rate
Scaffold porosity
Cell density
All of the above
Explanation - Controlled freezing and thawing are critical to maintain cell viability post‑storage.
Correct answer is: Cryopreservation rate
Q.90 Which of the following is a major hurdle in translating iPSC‑derived retinal cells to clinical use?
Low differentiation efficiency
Risk of tumorigenicity
High immunogenicity
Inability to culture in 3D
Explanation - Residual undifferentiated iPSCs can form teratomas, posing safety concerns.
Correct answer is: Risk of tumorigenicity
Q.91 What does 'sequential differentiation' refer to in tissue engineering?
Differentiation into one lineage at a time
Simultaneous differentiation into multiple lineages
Using a single growth factor for all cell types
Differentiation in a 2D environment only
Explanation - Sequential differentiation involves guiding cells through multiple lineage steps to form complex tissues.
Correct answer is: Simultaneous differentiation into multiple lineages
Q.92 Which of the following best describes the 'bioink viscosity' effect on printability?
Higher viscosity leads to better shape fidelity but harder extrusion
Lower viscosity reduces cell viability
Viscosity has no effect on print resolution
Viscosity determines the degradation rate of the scaffold
Explanation - Balancing viscosity is key: too low yields poor shape, too high requires high pressure.
Correct answer is: Higher viscosity leads to better shape fidelity but harder extrusion
Q.93 Which cell type is commonly used in engineered liver constructs for drug metabolism studies?
Hepatocyte‑like cells from iPSCs
Cardiomyocytes
Neurons
Chondrocytes
Explanation - iPSC‑derived hepatocyte‑like cells retain metabolic enzymes useful for toxicity testing.
Correct answer is: Hepatocyte‑like cells from iPSCs
Q.94 What is the primary purpose of using 'shear‑stress‑sensitive' scaffolds?
To resist fluid flow
To enhance cell adhesion under flow conditions
To degrade faster under mechanical stress
To block immune cell infiltration
Explanation - Shear‑stress‑sensitive materials respond to fluid dynamics, promoting endothelialization.
Correct answer is: To enhance cell adhesion under flow conditions
Q.95 Which of the following is a hallmark of a 'clinical‑grade' cell therapy product?
Non‑GMP production
Use of animal‑derived components
Compliance with GMP and regulatory approvals
Uncontrolled cell proliferation
Explanation - Clinical‑grade products must meet stringent GMP standards and regulatory requirements.
Correct answer is: Compliance with GMP and regulatory approvals
Q.96 Which of these techniques can be used to measure the stiffness of a hydrogel scaffold?
Dynamic mechanical analysis (DMA)
Gel electrophoresis
Flow cytometry
Spectrophotometry
Explanation - DMA measures viscoelastic properties like stiffness and modulus of hydrogels.
Correct answer is: Dynamic mechanical analysis (DMA)
Q.97 Which factor is most critical when choosing a scaffold for cartilage tissue engineering?
High electrical conductivity
Mechanical properties resembling native cartilage
Fast degradation
Low porosity
Explanation - Cartilage requires a balance of stiffness and flexibility to function mechanically.
Correct answer is: Mechanical properties resembling native cartilage
Q.98 What is the main advantage of using 'dynamic compression' in engineered bone tissue?
It reduces cell death
It promotes osteogenic differentiation
It increases scaffold porosity
It sterilizes the construct
Explanation - Mechanical loading mimics bone loading, enhancing mineral deposition and cell maturation.
Correct answer is: It promotes osteogenic differentiation
Q.99 Which of the following is NOT a characteristic of a 'bioactive ceramic' scaffold?
Supports osteoconduction
Is inherently biodegradable
Can release therapeutic ions
Is electrically conductive
Explanation - Bioactive ceramics (e.g., hydroxyapatite) are not known for electrical conductivity.
Correct answer is: Is electrically conductive
Q.100 What does the term 'in‑silico modeling' refer to in tissue engineering?
Physical testing of scaffolds
Computer simulations to predict tissue behavior
In vitro cell culture
Animal implantation studies
Explanation - In‑silico modeling uses computational tools to simulate mechanical, biochemical, and transport phenomena.
Correct answer is: Computer simulations to predict tissue behavior
Q.101 Which of the following is a commonly used method to evaluate the immunogenicity of engineered tissues?
ELISA for cytokines
PCR for viral genes
Mass spectrometry of scaffold
Chromatography of culture media
Explanation - Measuring cytokine profiles (e.g., IL‑6, TNF‑α) indicates inflammatory responses.
Correct answer is: ELISA for cytokines
Q.102 What is a key feature of a 'smart scaffold' in regenerative medicine?
It can change its properties in response to stimuli
It is purely passive
It degrades in less than 24 hours
It contains no cells
Explanation - Smart scaffolds respond to changes such as pH, temperature, or electrical signals.
Correct answer is: It can change its properties in response to stimuli
Q.103 Which of the following is a typical endpoint for evaluating angiogenesis in an engineered tissue?
Number of apoptotic cells
Extent of vascular network formation
Total scaffold weight
Gene expression of osteogenic markers
Explanation - Angiogenesis is measured by vessel density, length, and perfusion in the tissue.
Correct answer is: Extent of vascular network formation
Q.104 Which of these molecules is commonly used to cross‑link gelatin hydrogels?
Glutaraldehyde
Genipin
Ethylenediaminetetraacetic acid (EDTA)
Tannic acid
Explanation - Genipin is a natural cross‑linker that is less cytotoxic than glutaraldehyde.
Correct answer is: Genipin
Q.105 What is the main purpose of adding 'micro‑RNA (miRNA)' to cell cultures in tissue engineering?
To serve as a scaffold
To regulate gene expression post‑transcriptionally
To provide structural support
To act as an antibiotic
Explanation - miRNAs modulate the expression of target genes involved in differentiation and regeneration.
Correct answer is: To regulate gene expression post‑transcriptionally
Q.106 Which of the following is a challenge associated with 3D printing of vascularized tissues?
Achieving high resolution
Ensuring long‑term patency of micro‑vessels
Finding suitable bioinks
All of the above
Explanation - Vascularization requires precise printing, stable vessels, and compatible bioinks.
Correct answer is: All of the above
Q.107 Which of the following is NOT a typical component of a 'bioreactor culture media' for stem cells?
Defined growth factors
Serum substitute
Antibiotic/antimycotic
High glucose
Explanation - Standard media use physiological glucose levels; excessive glucose can alter differentiation.
Correct answer is: High glucose
Q.108 What is the main function of 'micro‑tissue constructs' in drug screening?
To replace animal testing completely
To provide more physiologically relevant models than 2D cultures
To increase the speed of cell proliferation
To reduce the cost of drug manufacturing
Explanation - Micro‑tissues mimic 3D cell–cell and cell–ECM interactions, improving predictive value.
Correct answer is: To provide more physiologically relevant models than 2D cultures
Q.109 Which of the following is a key parameter for controlling oxygen levels in a perfusion bioreactor?
Flow rate
Media pH
Light exposure
Temperature alone
Explanation - Flow rate directly influences oxygen transfer and shear forces in the bioreactor.
Correct answer is: Flow rate
Q.110 Which of the following best describes 'extracellular vesicle (EV)' therapy?
Injecting whole cells into the body
Using secreted vesicles from stem cells for paracrine effects
Genetically editing target cells
Administering antibiotics to infected tissues
Explanation - EVs carry proteins, RNAs, and lipids that mediate tissue repair without delivering cells.
Correct answer is: Using secreted vesicles from stem cells for paracrine effects
Q.111 Which of the following is an advantage of using 'dual‑stage' bioreactors?
Simultaneous perfusion and mechanical stimulation
Reduced manufacturing time
Higher nutrient diffusion
All of the above
Explanation - Dual‑stage designs combine perfusion and mechanical cues to mimic physiological conditions.
Correct answer is: All of the above
Q.112 Which of the following is NOT a typical function of a 'spheroid‑based' organoid system?
Mimicking 3D cell–cell interactions
Allowing high‑throughput drug screening
Providing uniform nutrient diffusion to all cells
Enabling co‑culture of multiple cell types
Explanation - Spheroids have limited diffusion depth, creating gradients rather than uniform supply.
Correct answer is: Providing uniform nutrient diffusion to all cells
Q.113 Which of these is a major consideration when using a 'photocrosslinkable' hydrogel in tissue engineering?
Light penetration depth
Temperature sensitivity
Presence of oxygen
All of the above
Explanation - Photocrosslinking requires appropriate light dose, temperature control, and oxygen levels.
Correct answer is: All of the above
Q.114 Which cell type is most commonly used for engineering blood vessels in vitro?
Endothelial cells
Chondrocytes
Neural stem cells
Fibroblasts
Explanation - Endothelial cells line blood vessels and are essential for vascular tissue engineering.
Correct answer is: Endothelial cells
Q.115 Which of the following is a key parameter for evaluating the degradation profile of a biodegradable scaffold?
Mass loss over time
Mechanical stiffness retention
pH of the surrounding medium
All of the above
Explanation - Degradation is assessed by mass loss, mechanical changes, and pH shifts in the media.
Correct answer is: All of the above
Q.116 What is the purpose of using 'hydrogel micro‑gel' particles in 3D printing?
To increase print resolution
To act as sacrificial material for channels
To improve scaffold mechanical strength
To provide electrical conductivity
Explanation - Micro‑gel particles can be dissolved to create channels, enabling vascularization.
Correct answer is: To act as sacrificial material for channels
Q.117 Which of the following is a commonly used method for assessing cell proliferation within 3D cultures?
MTT assay
EdU incorporation assay
Western blotting
Flow cytometry of cell cycle markers
Explanation - EdU labels newly synthesized DNA, allowing measurement of proliferating cells in 3D matrices.
Correct answer is: EdU incorporation assay
Q.118 Which of the following best describes the 'cell seeding density' influence on osteogenic differentiation?
Higher density always enhances differentiation
Optimal density balances cell–cell signaling and nutrient availability
Density has no effect
Low density promotes differentiation
Explanation - Too high density can cause hypoxia; too low may limit paracrine signals.
Correct answer is: Optimal density balances cell–cell signaling and nutrient availability
Q.119 What is a critical consideration when using 'nanoparticle‑loaded' scaffolds for drug delivery?
Nanoparticle size distribution
Scaffold porosity
Release kinetics
All of the above
Explanation - Size, porosity, and release profile all influence drug release efficacy.
Correct answer is: All of the above
Q.120 Which of the following is a major advantage of using 'electrospun' fibrous scaffolds?
High porosity with nano‑scale fibers
Simplified fabrication process
Inherent electrical conductivity
Rapid degradation in vivo
Explanation - Electrospinning creates nanofibrous mats that mimic the native ECM structure.
Correct answer is: High porosity with nano‑scale fibers
Q.121 What is the main reason for using 'pre‑vascularized' scaffolds in large tissue constructs?
To speed up scaffold synthesis
To provide immediate blood flow after implantation
To reduce scaffold cost
To enhance electrical stimulation
Explanation - Pre‑vascularization reduces hypoxia by establishing a vascular network before implantation.
Correct answer is: To provide immediate blood flow after implantation
Q.122 Which of the following best describes the 'mammalian‑cell‑derived extracellular matrix (MCM)'?
An artificial synthetic polymer
A decellularized matrix enriched in proteins
A pure collagen solution
A mixture of bacterial peptides
Explanation - MCM retains native ECM proteins, enhancing cell adhesion and function.
Correct answer is: A decellularized matrix enriched in proteins
Q.123 Which of these is a key challenge in integrating engineered neural tissues with host nervous systems?
Establishing electrical connectivity
Achieving mechanical strength
Preventing scaffold degradation
Increasing scaffold porosity
Explanation - Functional integration requires synaptic and electrical coupling with host neurons.
Correct answer is: Establishing electrical connectivity
Q.124 Which of the following is an advantage of using a 'dynamic bioreactor' over a static culture for cartilage engineering?
Lower nutrient consumption
Increased mechanical loading, enhancing matrix deposition
Reduced scaffold degradation
Simpler operation
Explanation - Dynamic loading simulates joint movement, promoting cartilage ECM production.
Correct answer is: Increased mechanical loading, enhancing matrix deposition
Q.125 What does the 'spheroid‑to‑organoid' transition involve?
Adding vascular cells to a spheroid
Expanding the spheroid into a larger, structured tissue
Changing the culture medium
Applying electrical stimulation
Explanation - Organoids grow from spheroids into organized, multi‑cellular structures mimicking organs.
Correct answer is: Expanding the spheroid into a larger, structured tissue
Q.126 Which of the following is a commonly used 'bio‑inspired' material in tissue engineering?
Silk fibroin
Polystyrene
PVC
PET
Explanation - Silk fibroin is a natural protein with excellent mechanical and biocompatible properties.
Correct answer is: Silk fibroin
Q.127 Which of the following is a key feature of a 'dual‑gel' scaffold system?
Two distinct cross‑linking chemistries for sequential gelation
One gel that dissolves upon injection
A single gel with variable stiffness
A gel that changes color with pH
Explanation - Dual‑gel systems allow spatial control of material properties via two chemistries.
Correct answer is: Two distinct cross‑linking chemistries for sequential gelation
Q.128 What is the purpose of including 'biochemical cues' (e.g., growth factors) in a scaffold?
To degrade the scaffold faster
To direct cell fate and function
To reduce mechanical strength
To act as an antibiotic
Explanation - Biochemical cues guide differentiation, proliferation, and maturation of embedded cells.
Correct answer is: To direct cell fate and function
Q.129 Which of the following best describes the 'shear‑stress threshold' for endothelial cell alignment?
1–10 dyn/cm²
50–100 dyn/cm²
0.01–0.1 dyn/cm²
100–200 dyn/cm²
Explanation - Endothelial cells align parallel to flow when exposed to 1–10 dyn/cm² of shear stress.
Correct answer is: 1–10 dyn/cm²
Q.130 Which of the following is a key parameter in designing a 'vascularized organoid'?
Inclusion of endothelial cells
Use of high‑glycemic media
Absence of growth factors
Non‑porous scaffold
Explanation - Endothelial cells are required to form vascular networks within organoids.
Correct answer is: Inclusion of endothelial cells
Q.131 Which of the following is a major risk factor when using iPSC‑derived cardiomyocytes for therapy?
Teratoma formation
Arrhythmogenic potential
High immunogenicity
Rapid differentiation
Explanation - Engineered cardiomyocytes can cause arrhythmias if they do not integrate electrically.
Correct answer is: Arrhythmogenic potential
Q.132 What is the main advantage of using a 'hydrogel‑based' cell delivery system for spinal cord injury?
Rapid degradation
Electrical conductivity
Cell protection and localized delivery
High mechanical stiffness
Explanation - Hydrogels encapsulate cells, protect them, and localize them at the injury site.
Correct answer is: Cell protection and localized delivery
Q.133 Which of the following is a key criterion for selecting a 'biodegradable polymer' for scaffold fabrication?
Degradation rate matching tissue regeneration rate
High cost
Low mechanical strength
Poor biocompatibility
Explanation - The scaffold should degrade at a rate that supports tissue formation without premature loss of support.
Correct answer is: Degradation rate matching tissue regeneration rate
Q.134 Which of the following best describes 'self‑healing' scaffolds?
Scaffolds that can regenerate after being damaged
Scaffolds that can adjust porosity in vivo
Scaffolds that release growth factors continuously
Scaffolds that can be sterilized multiple times
Explanation - Self‑healing materials can repair micro‑damage autonomously, maintaining structural integrity.
Correct answer is: Scaffolds that can regenerate after being damaged
Q.135 Which of the following is a common method for delivering oxygen to cells in a static scaffold culture?
Adding oxygen‑soluble perfluorocarbons
Increasing ambient humidity
Reducing media volume
Using magnetic fields
Explanation - Perfluorocarbons can dissolve large amounts of O₂, enhancing cell survival in 3D constructs.
Correct answer is: Adding oxygen‑soluble perfluorocarbons
Q.136 Which of the following is NOT a typical feature of an 'in‑vitro disease model' built with tissue‑engineered constructs?
Recapitulation of disease‑specific cellular phenotypes
High reproducibility
Large‑scale production
Use of patient‑derived cells
Explanation - In‑vitro disease models focus on fidelity rather than high‑throughput production.
Correct answer is: Large‑scale production
Q.137 Which of the following is a critical factor for ensuring the mechanical integrity of a 3D‑printed cartilage scaffold?
High porosity
Low cross‑link density
Optimized printing temperature
Rigid polymer composition
Explanation - Cartilage scaffolds require sufficient stiffness to support mechanical loads.
Correct answer is: Rigid polymer composition
Q.138 What is a common method to evaluate the immunomodulatory properties of MSCs?
Measuring secreted IL‑10 and TGF‑β levels
Assessing DNA repair capacity
Measuring electrical impedance
Testing mechanical stiffness
Explanation - IL‑10 and TGF‑β are key anti‑inflammatory cytokines released by MSCs.
Correct answer is: Measuring secreted IL‑10 and TGF‑β levels
Q.139 Which of the following is a typical endpoint for evaluating the osteo‑inductive potential of a scaffold?
Alkaline phosphatase activity
Neurite outgrowth
Collagen type II production
Myosin heavy chain expression
Explanation - ALP activity is an early marker of osteogenic differentiation.
Correct answer is: Alkaline phosphatase activity
Q.140 Which of the following best describes a 'multiscale' tissue‑engineering approach?
Integrating materials at the nano, micro, and macro levels
Using only nanoscale features
Using only macroscale structures
Avoiding any scaling issues
Explanation - Multiscale design ensures mechanical integrity and cellular interaction across dimensions.
Correct answer is: Integrating materials at the nano, micro, and macro levels
Q.141 Which of the following is a key challenge when designing scaffolds for bone–cartilage interface repair?
Uniform stiffness
Gradient mechanical properties
Rapid degradation
Lack of cell sources
Explanation - The interface requires gradual change in stiffness to connect bone and cartilage seamlessly.
Correct answer is: Gradient mechanical properties
Q.142 Which of the following is an advantage of 'cell‑sheet' engineering for cardiac patches?
Avoids scaffold‑induced immunogenicity
Simplifies vascularization
Reduces mechanical strength
Increases cell death
Explanation - Cell sheets maintain cell‑cell junctions and ECM, improving integration and reducing immune response.
Correct answer is: Avoids scaffold‑induced immunogenicity
Q.143 Which of the following is a commonly used marker for assessing chondrogenic differentiation?
Collagen type I
Collagen type II
Osteopontin
Keratin 18
Explanation - Collagen II is the principal collagen in hyaline cartilage, a marker of chondrogenesis.
Correct answer is: Collagen type II
Q.144 What is the main role of 'platelet‑rich plasma (PRP)' in regenerative medicine?
Providing a scaffold material
Delivering growth factors to enhance healing
Acting as an antibiotic
Serving as a cell source
Explanation - PRP contains high levels of growth factors (e.g., TGF‑β, PDGF) that stimulate tissue repair.
Correct answer is: Delivering growth factors to enhance healing
Q.145 Which of the following is a key factor in determining the 'printability' of a bioink?
Viscosity
Cell viability
Cross‑linking kinetics
All of the above
Explanation - Printability depends on rheology, viability, and rapid cross‑linking to maintain shape.
Correct answer is: All of the above
Q.146 Which of the following is a commonly used method to sterilize 3D‑printed scaffolds?
Gamma irradiation
Plasma sterilization
Low‑temperature hydrogen peroxide gas plasma
All of the above
Explanation - Each method is chosen based on material sensitivity and sterility requirements.
Correct answer is: All of the above
Q.147 Which of the following best explains 'immune privileged' cells?
Cells that do not elicit an immune response when transplanted
Cells that are immune cells themselves
Cells that can suppress the immune system
Cells that are only found in the brain
Explanation - Immune‑privileged cells, such as MSCs, can survive in allogeneic environments with minimal rejection.
Correct answer is: Cells that do not elicit an immune response when transplanted
Q.148 Which of the following is NOT typically used to assess the mechanical performance of engineered cartilage?
Compression testing
Tensile testing
Shear rheology
Electrical impedance spectroscopy
Explanation - While EIS can assess ECM composition, it is not a primary mechanical test for cartilage.
Correct answer is: Electrical impedance spectroscopy
Q.149 What is the main advantage of using a 'cell‑free' scaffold for regenerative purposes?
It eliminates the need for cell sourcing and handling
It accelerates cell proliferation
It guarantees immediate functional integration
It reduces scaffold degradation
Explanation - Cell‑free scaffolds rely on host cells for regeneration, avoiding complex cell culture steps.
Correct answer is: It eliminates the need for cell sourcing and handling
Q.150 Which of the following is a typical marker for assessing vascular endothelial differentiation?
CD31
CD45
Oct4
Nestin
Explanation - CD31 (PECAM‑1) is a hallmark endothelial cell surface marker.
Correct answer is: CD31
Q.151 Which of the following is a major drawback of using animal‑derived xenogenic matrices in human therapy?
High cost
Potential for immune rejection and disease transmission
Lack of mechanical strength
Low cell affinity
Explanation - Xenogenic matrices can carry zoonotic agents and provoke strong immune responses.
Correct answer is: Potential for immune rejection and disease transmission
Q.152 Which of the following best describes a 'smart drug delivery' system within a tissue scaffold?
Passive release over weeks
Responsive release triggered by stimuli (pH, temperature)
Immediate release upon implantation
No release of drug
Explanation - Smart systems release therapeutic agents in response to environmental cues, enhancing efficacy.
Correct answer is: Responsive release triggered by stimuli (pH, temperature)
Q.153 Which of the following is a key consideration for the use of '3D printed' bone grafts?
Mechanical compatibility with native bone
Rapid degradation
Low porosity
No need for vascularization
Explanation - 3D printed grafts must match bone's mechanical properties to load‑bear effectively.
Correct answer is: Mechanical compatibility with native bone
Q.154 Which of the following is a typical method to measure the permeability of a scaffold?
Fluorescence recovery after photobleaching (FRAP)
Tensile testing
Rheology
Flow rate in a permeation chamber
Explanation - Permeability is quantified by measuring fluid flow across the scaffold under a pressure gradient.
Correct answer is: Flow rate in a permeation chamber
Q.155 Which of the following best describes the 'hydrogel‑based drug release' mechanism?
Diffusion through the gel matrix
Chemical degradation of the gel
Both A and B
None of the above
Explanation - Drug release can occur by diffusion or by hydrogel degradation over time.
Correct answer is: Both A and B
Q.156 Which of the following is a key challenge in maintaining 'cell viability' in large‑scale 3D constructs?
Limited nutrient diffusion
Excessive oxygen supply
High scaffold stiffness
Low mechanical strength
Explanation - Mass transport limitations in large constructs lead to hypoxic cores and cell death.
Correct answer is: Limited nutrient diffusion
Q.157 What is the main function of a 'biodegradable polymer blend' in a composite scaffold?
To provide electrical conductivity
To combine mechanical strength with controlled degradation
To act as an antibiotic
To reduce scaffold porosity
Explanation - Polymer blends allow tuning of stiffness and degradation rate simultaneously.
Correct answer is: To combine mechanical strength with controlled degradation
Q.158 Which of the following is a primary benefit of using 'spheroid‑based' cardiac tissue constructs?
Improved electrical coupling and synchronous beating
Simplified fabrication
Reduced cost
All of the above
Explanation - Spheroids promote cell–cell interactions, essential for cardiac function.
Correct answer is: Improved electrical coupling and synchronous beating