[Week 3] NPTEL Organ Printing Assignment Answers 2023

NPTEL Organ Printing Assignment Solutions 2023

NPTEL Organ Printing Week 3 Assignment Answers 2023

1. Which fundamental attributes should an ideal bioink possess to support successful bioprinting of complex tissue structures?

• High electrical conductivity and resistance to temperature changes
• Biocompatibility, suitable rheological properties, and support for cellular viability
• Bright color and luminescence for real-time visualization
• Low viscosity and rapid degradation for efficient printing
• Both c and d

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2. What considerations are crucial when selecting the base material for bioink formulation to ensure cell survival and tissue-specific functions?

• Optical properties and fluorescence behavior under specific wavelengths
• Economic cost and ease of mass production
• Mechanical stability, biodegradability, and resemblance to native tissue environment
• Water solubility and ease of handling in the printing process
• None of the above

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3. Explain the significance of bioink biocompatibility and how it influences the cellular response and integration within bioprinted tissues.

• Bioink biocompatibility is negligible in bioprinting; cell viability is usually dependent on cell type
• Biocompatibility affects bioink color and opacity; it doesn’t impact cellular behavior
• Bioink biocompatibility can yield cell proliferation; non-biocompatible bioinks hinder cell growth
• Biocompatible bioinks ensures cell survival and function, supporting tissue regeneration
• Both a and b

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4. Consider the role of cell-laden bioinks in single-material and multimaterial bioink systems for bioprinting. How can these bioinks be engineered to support specific tissue functions and interactions within a complex tissue construct?

• Cell-laden bioinks are unnecessary for bioprinting; scaffolds alone are sufficient
• Cell-laden bioinks enhance structural integrity but hinder cell differentiation
• Cell-laden bioinks facilitate cell communication and tissue maturation in both systems
• Single-material bioinks rely on cell-laden bioinks, while multimaterial systems do not

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5. The inkjet bioprinting technique requires –

Low viscous bioink
Moderate viscous bioink
High viscous bioink
All of the above

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6. Highly viscous bioink –

• Maintains the initial shape after deposition
• Allows deformation of the printed structure
• Facilitates collapsing of the structure
• None of the above

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7. What is the challenge with bioinks with dissimilar swelling behavior?

• Deformation of the structure
• Disintegration of the structure
• Stability of the structure
• All of the above
• None of the above

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8. Which factor is critical for the success of a bioink in bioprinting?

• Color and appearance
• Viscosity and printability
• Biodegradability and disposal
• Fluorescence and luminescence
• All of the above

Answer :- 

9. The printing fidelity is very good with –

• Low viscous bioink
• Moderate viscous bioink
• High viscous bioink
• All of the above

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10. Risk of laser exposure is associated with what kind of crosslinking –

• Physical crosslinking
• Chemical crosslinking
• Photo crosslinking
• All of the above
• Both b and c

Answer :- 

11. What is the purpose of crosslinking in the context of hydrogel-based bioinks?

• To increase the fluidity of the bioink
• To enhance the transparency of the printed structure
• To improve the biocompatibility of the hydrogel
• To stabilize the printed structure and maintain its shape
• All of the above

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12. High polymer concentrations can be restrictive environments for cell migration due to –

• Dense polymeric network
• Open porous network
• Softer microenvironment
• All of the above
• Both b and c

Answer :- 

13. Shear Thinning behavior is related to –

• Increase in viscosity with increase in shear rate
• Decrease in viscosity with increase in shear rate
• No change in viscosity with increase in shear rate
• Increase in viscosity during bioprinting
• None of the above

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14. Which method is commonly used for crosslinking hydrogels in 3D bioprinting?

• Microwave irradiation
• Mechanical agitation
• Freezing and thawing cycles
• Chemical agents or UV light exposure
• None of the above

Answer :- 

15. Yield stress is related to –

• The critical stress that that must be overcome to initiate flow
• Polymer chains form of a fragile, physically crosslinked network
• Break down of physically crosslinked network by shear forces and reorganization of the network
• All of the above
• None of the above

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16. Gelatin based bioink shows –

• Ionic Crosslinking
• Stereocomplex Crosslinking
• Thermal Crosslinking
• None of the above
• All of the above

Answer :- 

17. Which crosslinking does provide better structural stability and higher mechanical property?

• Physical crosslinking
• Chemical crosslinking
• Photo crosslinking
• All of the above
• None of the above

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18. What advantage does a multimaterial bioink system offer over a single-material system?

• Faster printing speed
• Lower cost of production
• Ability to create complex, heterogeneous structures
• Reduced need for cell culturing
• Both c and d

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19. Arrange the printability of a bioink having polymer with (Low to High)

• High molecular weight>Moderate molecular weight >Low molecular weight
• Low molecular weight > High molecular weight>Moderate molecular weight
• Low molecular weight >Moderate molecular weight>High molecular weight

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20. Shear stress induced cell damage is high in

• Inkjet bioprinting
• Laser-assisted bioprinting
• Extrusion bioprinting
• All of the above
• None of the above

Answer :- 

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NPTEL Organ Printing Week 2 Assignment Answers 2023

1. What is the main advantage of Laser-assisted Bioprinting over other bioprinting techniques?

• High printing speed for large-scale tissue constructs
• Precise control of cell placement and high cell viability
• Ability to print tissues without the need for supporting structures
• Compatibility with a wide range of bioinks, including hydrogels and polymers

Answer :- Precise control of cell placement and high cell viability.

2. How does Laser-induced Forward Transfer (LIFT) differ from traditional laser printing in Laser-assisted Bioprinting?

• LIFT uses higher laser power, leading to cell damage
• LIFT involves laser ablation of tissue for 2D printing applications
• LIFT transfers living cells without damaging them in a contact-free manner
• LIFT uses ink cartridges to dispense bioink onto the substrate

Answer :- LIFT transfers living cells without damaging them in a contact-free manner.

3. The form of material in the AFA-LIFT technique is –

• Powder
• Granules
• Filament
• Ribbon

Answer :- Ribbon

4. Which bioprinting technology provides a wide choice of materials?

• Inkjet printing
• Extrusion bioprinting
• Laser-assisted bioprinting
• All of the above

Answer :- Extrusion bioprinting

5. How does Extrusion-based Bioprinting differ from Inkjet Bioprinting in terms of bioink delivery?

• Extrusion-based Bioprinting uses continuous strands of bioink, while Inkjet Bioprinting relies on droplet ejection
• Extrusion-based Bioprinting requires contact with the substrate, while Inkjet Bioprinting is contactless
• Extrusion-based Bioprinting uses a laser to solidify the bioink, while Inkjet Bioprinting utilizes UV light
• Extrusion-based Bioprinting allows the use of multiple materials, while Inkjet Bioprinting is limited to a single bioink type

Answer :- Extrusion-based Bioprinting uses continuous strands of bioink, while Inkjet Bioprinting relies on droplet ejection.

6. Which one of bioprinters is most expensive?

• Inkjet printing
• Extrusion bioprinting
• Laser-assisted bioprinting
• All of the above

Answer :- Laser-assisted bioprinting

7. High cell densities can be bioprinted with –

• Inkjet printing
• Extrusion bioprinting
• Laser-assisted bioprinting
• All of the above

Answer:- Extrusion bioprinting

8. Complex 3D geometries can be very well printed with

• Inkjet printing
• Extrusion bioprinting
• Laser-assisted bioprinting
• All of the above

Answer :- Extrusion bioprinting

9. Low power laser pulses operating in the UV or near-UV wavelength and sacrificial energy absorbing layer made of a biopolymer instead of metals are used in –

• AFA-LIFT
• LIFT
• MAPLE DW
• BioLP

Answer :- MAPLE DW

10. 800 nm laser beam to move the cells in a liquid suspension (usually in cell media), also the laser beam is coupled with hollow optical fibers in –

• AFA-LIFT
• LG DW
• MAPLE DW
• LIFT

Answer :- LG DW

11. Biopolymer-based absorbing layer is present in –

• AFA-LIFT
• LG DW
• MAPLE DW
• LIFT

Answer :- LG DW

12. Arrange the bioprinting technologies in terms of capability of using biomaterials viscosities (Low to High)

• Inkjet bioprinting > Extrusion bioprinting > Laser-assisted bioprinting
• Inkjet bioprinting > Laser-assisted bioprinting > Extrusion bioprinting
• Extrusion bioprinting > Inkjet bioprinting > Laser-assisted bioprinting

Answer :- Inkjet bioprinting > Laser-assisted bioprinting > Extrusion bioprinting.

13. Arrange the bioprinting technologies in terms their Print speed (Low to High)

• Inkjet bioprinting > Extrusion bioprinting > Laser-assisted bioprinting
• Inkjet bioprinting > Laser-assisted bioprinting > Extrusion bioprinting
• Extrusion bioprinting > Laser-assisted bioprinting > Inkjet bioprinting

Answer :- Inkjet bioprinting > Laser-assisted bioprinting > Extrusion bioprinting.

14. What is the main role of the support bath in 3D Bioprinting?

To provide structural integrity to the printed tissue construct
To prevent cross-contamination between different bioinks
To act as a barrier for maintaining a sterile bioprinting environment
To provide mechanical support and reduce the effects of gravity during printing

Answer :- To provide mechanical support and reduce the effects of gravity during printing.

15. Which factor should be primarily considered when selecting the optimal support bath for a specific bioprinting application?

• The bath’s ability to dissolve in various solvents and media
• The color and transparency of the support bath
• The density and melting point of the support bath material
• The printing temperature required for the chosen bioink

Answer :- The printing temperature required for the chosen bioink.

16. In 3D bioprinting using a support bath, what is the role of sacrificial materials?

• To act as a buffer to control pH during the printing process
• To serve as a nutrient-rich medium for cell growth
• To provide structural support during printing and dissolve post-printing
• To enhance cell adhesion to the substrate and prevent detachment

Answer :- To provide structural support during printing and dissolve post-printing.

17. What distinguishes Drop-on-Demand (DOD) Bioprinting from Continuous Inkjet (CIJ) Bioprinting?

• DOD Bioprinting uses a single bioink type, while CIJ Bioprinting allows for multiple materials
• CIJ Bioprinting requires contact with the substrate, while DOD Bioprinting is non-contact
• DOD Bioprinting prints continuous strands of bioink, while CIJ Bioprinting prints individual droplets
• CIJ Bioprinting achieves higher printing speeds compared to DOD Bioprinting

Answer :- DOD Bioprinting prints continuous strands of bioink, while CIJ Bioprinting prints individual droplets.

18. What role does the “ribbon” play in Laser-assisted Bioprinting?

• It is a specialized nozzle that deposits the bioink on the substrate
• It acts as a transfer medium for cells and biomaterials during the printing process
• It supports the 3D printed tissue construct during post-printing handling
• It is a laser-scanning component that controls the spatial arrangement of the bioink

Answer :- It acts as a transfer medium for cells and biomaterials during the printing process.

19. Most control over cell distribution within the printed tissue construct?

• Inkjet printing
• Extrusion bioprinting
• Laser-assisted bioprinting
• None of the above

Answer :- Laser-assisted bioprinting

20. A tissue engineering team aims to create a bioartificial liver using Extrusion Bioprinting. What makes Extrusion Bioprinting suitable for this application?

• Capability to print miniature functional liver lobules
• Compatibility with metallic inks for liver support structures
• High printing speed for large-scale liver constructs
• Ability to print conductive materials for liver-electrode interfaces

Answer :- Capability to print miniature functional liver lobules

NPTEL Organ Printing Week 1 Assignment Answers 2023

1. What makes 3D bioprinting different from traditional tissue engineering techniques?

• 3D bioprinting only uses biological cells as building blocks
• 3D bioprinting does not require the use of scaffolds
• 3D bioprinting is a faster process with immediate results
• 3D bioprinting allows for precise spatial arrangement of cells and biomaterials

Answer :- 3D bioprinting allows for precise spatial arrangement of cells and biomaterials.

Traditional tissue engineering techniques typically involve growing cells on scaffolds in a controlled environment to create functional tissue. In contrast, 3D bioprinting is a more advanced method that enables the precise placement of cells, biomaterials, and growth factors in a layer-by-layer fashion to create complex 3D structures. This precision in spatial arrangement is a key differentiator of 3D bioprinting compared to traditional methods, and it has the potential to mimic the intricate architecture of natural tissues more accurately.

2. Which of the following best defines tissue engineering?

• The process of creating artificial organs for transplantation
• The use of nanotechnology to repair damaged tissues
• The application of engineering and biological principles to develop functional tissues
• The study of tissue structure under a microscope

Answer :- The application of engineering and biological principles to develop functional tissues.

Tissue engineering involves combining principles from both engineering and biology to design and develop functional tissue constructs that can replace, repair, or enhance damaged or diseased tissues in the human body. This field aims to create artificial tissues and organs for transplantation or to facilitate tissue repair and regeneration.

3. Which of the following is NOT a key component of tissue engineering?

• Scaffold or framework for tissue support
• Growth factors and signaling molecules
• Biodegradable materials for implantation
• Antibiotics for preventing infections

Answer :- Antibiotics for preventing infections.

While antibiotics can play a role in preventing infections associated with tissue engineering procedures, they are not a key component of tissue engineering itself. The main components of tissue engineering include:

Scaffold or framework for tissue support: This provides structural support for cells to grow and organize into functional tissue.

Growth factors and signaling molecules: These molecules are used to guide cell behavior, promote cell proliferation, and encourage tissue regeneration.

Biodegradable materials for implantation: Biodegradable materials are often used to create scaffolds that degrade over time as the tissue regenerates, eliminating the need for surgical removal.

4. Which type of bioink is commonly used in inkjet bioprinting?

• Plastic-based bioinks
• Synthetic polymers
• Hydrogels and cell-laden solutions
• Metal-based inks

Answer :- Hydrogels and cell-laden solutions

5. Which one is true for inkjet printing?

• Non-contact
• High-throughput
• High-resolution
• All of the above
• None of the above

Answer :- All of the above.

Inkjet printing, including bioprinting, typically offers the following characteristics:

Non-contact: Inkjet printing is a non-contact printing technique where droplets of ink (or bioink in bioprinting) are ejected from a print head without physically touching the substrate. This allows for precise deposition without damaging delicate materials.

High-throughput: Inkjet printing can be high-throughput, meaning it can rapidly deposit multiple droplets of ink or bioink in a short amount of time, which is beneficial for creating complex structures efficiently.

High-resolution: Inkjet printing can achieve high-resolution printing, allowing for the precise placement of droplets with fine control over the printed pattern. This is important for creating detailed and accurate structures.

6. The preprocessing step of bioprinting involves the following.

• Preparation of bioink
• Making the CAD model
• Bioprinting of 3D structure
• Incubation of the printed construct by providing all necessary conditions

Answer :- Making the CAD model.

Before the actual bioprinting process begins, a Computer-Aided Design (CAD) model of the desired 3D structure is created. This CAD model serves as a digital blueprint that guides the bioprinter in depositing the bioink layer by layer to build the intended tissue or structure. The preparation of the bioink and other steps typically follow the CAD model creation during the bioprinting workflow.

7. The processing step of bioprinting involves the following.

• Preparation of bioink
• Making the CAD model
• Bioprinting of 3D structure
• Incubation of the printed construct by providing all necessary conditions

Answer :- Bioprinting of 3D structure.

8. The post-processing step of bioprinting involves the following.

• Preparation of bioink
• Making the CAD model
• Bioprinting of 3D structure
• Incubation of the printed construct by providing all necessary conditions

Answer :- Incubation of the printed construct by providing all necessary conditions.

9. Which bioprinting technology has the following features – Drop-on-demand and non-contact material delivery

Extrusion-based bioprinting
Inkjet-based bioprinting
Laser-induced bioprinting
All of the above
None of the above

Answer :- Inkjet-based bioprinting

10. Biopaper is used for one of the bioprinting technology.

• Extrusion-based bioprinting
• Inkjet-based bioprinting
• Laser-induced bioprinting
• All of the above
• None of the above

Answer :- Inkjet-based bioprinting

11. The inkjet bioprinter can handle the following viscosity range.

High viscosity
Moderate viscosity
Low viscosity
All of the above

Answer :- Low viscosity

12. Which bioprinting technique can also be called as droplet-based bioprinting?

• Extrusion-based bioprinting
• Inkjet-based bioprinting
• Laser-induced bioprinting
• All of the above
• None of the above

Answer :- Inkjet-based bioprinting

13. The raw materials for bioprinting are the following.

Cells
Biomaterials
Bioactive factors
All of the above
None of the above

Answer :- All of the above.

The raw materials for bioprinting typically include:

Cells: Living cells are a crucial component in bioprinting. These cells can be sourced from various tissues and organs and are often used to create functional tissues and structures.

Biomaterials: Biomaterials serve as the scaffolds or matrices that provide structural support for the printed cells. These biomaterials can be natural or synthetic and should be biocompatible and suitable for cell growth and attachment.

Bioactive factors: Bioactive factors such as growth factors, cytokines, and signaling molecules are used to guide cell behavior, promote tissue regeneration, and enhance the functionality of the printed constructs.

14. Choice of a suitable bioprinting technique is highly dependent on the following.

• Desired application
• Biomaterial formulation
• Cell types
• All of the above

Answer :- All of the above.

15. What is the advantage of using inkjet bioprinting in tissue engineering?

It allows for the printing of electronics within the tissue structures
It provides a faster printing speed compared to other bioprinting techniques
It does not require any living cells, making it easier to handle
It offers high precision and the ability to create complex tissue architectures

Answer :- It offers high precision and the ability to create complex tissue architectures.