Advanced Bioinks for 3D Printing: A Materials Science Perspective The recent emergence of 3D printing technology in tissue engineering DESIGN PARAMETERS FOR ADVANCED BIOINK DEVELOPMENT MULTIMATERIAL BIOINKS FOR 3D PRINTING A Materials Science Perspective

1. Welcome
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4. Contents
1. Introduction
2. Types of bioprinting and biomaterial needed
3. Desired properties in bioink
4. Biofabrication Window
5. Advanced bioinks
a. Multimaterial bioink for 3D printing
b. Nanocomposite bioink for 3D printing
6. Conclusion
7. References
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5. Introduction
• 3D Bioprinting is a technology, where
bioinks mixed with living cells and
printed in 3D format to construct 3D
structure of natural tissue.
• Instead of plastic that we are using in
3D printing, here in bioprinting we use
bioinks.
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3D Bioprinter

6. • Bioprinting is specific for
manufacturing biological materials
like tissue & organs etc.
• 3D bioprinting is based on the layer
by layer precise positioning of
biological constituents.
• Patients own cells can be used for
construction of tissues & organs.
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Layer by layer deposition of material by
3D bioprinter
Bioprinting construct

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1.Extrusion
bioprinting
Bioink should have
higher viscosity for
proper shape fidelity.
Shear thinning
material is necessary.
2.Inkjet bioprinting
Biomaterial should
have low viscosity.
Should have low
thermal stress to
prevent heat damage
to the cells.
3.Laser assisted
Viscous material can
be used.
Print fidelity is be high
(accuracy of printing).
4.Stereolithography
 - Bioink should have
high mechanical
strength.
 - No need of curing.
 (Directly UV rays are
being applied)
Heater

8. DESIRED
PROPERTIES
IN BIOINK
Porosity of
construct
(Cytocompatibil-
ity)
Viscosity
(For uniform
cell
encapsulation)
Hydration
Degree
(Nutrient
diffusion)
Viscoelasticity
(Protect cells
from shear
stress)
Biocompatibility
(High cell
viability)
Shear-thinning
(Printability)
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9. Biofabrication Window
• The biofabrication window is a concept that describes the variables optimization that can
be made to design bioink by compromising between printability and biocompatibility.
• Biofabrication window is more if acceptable printability and biocompatibility can be
obtain by changing parameters of polymer.
• In contrast biofabrication window is less if acceptable printability and biocompatibility
can’t be obtained by changing parameters of polymer.
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10. Advanced bioinks
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Multimaterial Bioinks Nanocomposite Bioinks
 Two or more materials are combined
together.
 Nanoparticles are incorporated in biomaterial.
 Contain characteristics of both polymer
combined together.
 Small amount of nanoparticles added to
polymer can change various physical and
chemical characteristics of bioink.
 Strength is improved by crosslinking.  Can be used as targeting drug delivery vehicle
 Rheological properties can be modified by
combining different polymers.
 Lower risk of bacterial contamination.

11. Biocompatibility
Printability
Ideal
inks for
3D printing
Traditional
Bioinks
Ideal cell
culture
hydrogels
Advanced
Bioinks
Cytotoxic Proliferation
Cell adhesion
Deformities
Well printed
structure
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Graph showing characteristics of advanced bioink

12. a) Multimaterial bioinks for 3D bioprinting
• Multimaterial hydrogels are the
most widely investigated bioinks
to overcome the limitations of
single component hydrogels.
• Multi-head printer is used to print
a complex interwoven scaffold
consisting of hydrogel bioinks.
• At a time only one extruder prints.
• Heater can be attached to extruder
if the material is difficult to
extrude without melting.
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Multi-head bioprinter

13. • Advantages
• Characteristics of different polymers
can be combined.
• Better mimic native cellular
microenvironment.
• Better rheological characteristics.
• Better printability
• More crosslinking increase strength.
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Disadvantages
• Decreased cell compatibility.
• May loose structural integrity.
• Require more time for
printing.
• Curing step is required during
printing ( stimulate crosslink-
ing).

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Bioink components Bioink Robust Gel
Ex. Bioink consist of GelMA and PEG crosslinker.
• The length of PEG crosslinker can be modulated to control the mechanical properties
of printed structures.
• 3D printed structures show high cell viability and support cell proliferation.

15. b) Nanocomposite bioink for 3D bioprinting
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• Nanocomposite bioink have been
obtained from the combination of
hydrogel biomaterial and
nanoparticles.
• Nanomaterials are used like gold
nanoparticles, nanosilicates,
nanocellulose, hydroxyapatite, etc.
• Nanoparticles also called nanofillers
they reinforce hydrogel based
bioinks. Nanocomposite bioink

16. Types of
Nanoparticles
Carbonaceous Filler
Graphene, Carbon
Nanotubes
Metallic Nanoparticles
Gold Nanoparticles
Clay based Fillers
Laponite, Montmorillonite,
silica
Gold Nanoparticles
Laponite
silica
Nanoparticles 16

17. Advantages
• Enhanced electrical
conductivity
• Enhanced printability
• Enhanced strength
• Share thinning
• Improved functionality
Disadvantages
• Accumulate in specific
tissues
• May cause carcinogenic
effect
• May be immunogenic
• Not biodegradable
• High cost
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18. • Ex. Shear thinning hydrogels were
prepared by combining synthetic
nanosilicates with gelatin methacrylate
(GelMA).
• The addition of nanosilicates to GelMA
results in high print fidelity and structural
stability.
• After UV (curing) crosslinking increases
and printed hydrogel shows high
physiological stability.
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Shear thinning

19. Formation of Nanocomposite hydrogels
+
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20. Effect of adding Nanosilicate Nanoparticles
Printing Gelatin Methacrylate without
adding nanosilicate nanoparticles
Printing Gelatin Methacrylate with adding
nanosilicate nanoparticles
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21. Conclusion
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Desired
properties
in bioink
Shape retention
for long time
Biodegradability
Cytocompatibility
Printability
High
mechanical
strength
Structural
fidelity

22. Conclusion
Desired properties in
bioink can be obtained
and improved by
Increased polymer
density
Increased
crosslinking
Formulating
multimaterial
hydrogels
By adding
nanoparticles to
bioink
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23. References
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Jun;12(6):478-9.
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Cell-imprinted substrates direct the fate of stem cells. ACS nano. 2013 Oct 22;7(10):8379-84.
• Gaharwar AK, Peppas NA, Khademhosseini A. Nanocomposite hydrogels for biomedical
applications. Biotechnology and bioengineering. 2014 Mar;111(3):441-53.
• Hoffman AS. Hydrogels for biomedical applications. Advanced drug delivery reviews. 2012 Dec
1;64:18-23.
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extrusion-based 3D-printing. Journal of Materials Chemistry B. 2015;3(20):4105-17.
• Melchels FP, Domingos MA, Klein TJ, Malda J, Bartolo PJ, Hutmacher DW. Additive manufacturing of
tissues and organs. Progress in polymer science. 2012 Aug 1;37(8):1079-104.
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24. References
• Murphy SV, Atala A. 3D bioprinting of tissues and organs. Nature biotechnology. 2014
Aug;32(8):773-85.
• Pati F, Gantelius J, Svahn HA. 3D bioprinting of tissue/organ models. Angewandte Chemie
International Edition. 2016 Apr 4;55(15):4650-65.
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May 1;34(5):356-7.
• Malda J, Visser J, Melchels FP, Jüngst T, Hennink WE, Dhert WJ, Groll J, Hutmacher DW. 25th
anniversary article: engineering hydrogels for biofabrication. Advanced materials. 2013
Sep;25(36):5011-28.
• Bertassoni LE, Cecconi M, Manoharan V, Nikkhah M, Hjortnaes J, Cristino AL, Barabaschi G,
Demarchi D, Dokmeci MR, Yang Y, Khademhosseini A. Hydrogel bioprinted microchannel networks
for vascularization of tissue engineering constructs. Lab on a Chip. 2014;14(13):2202-11.
• Carrow JK, Gaharwar AK. Bioinspired polymeric nanocomposites for regenerative medicine.
Macromolecular Chemistry and Physics. 2015 Feb;216(3):248-64.
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25. References
• Discher DE, Mooney DJ, Zandstra PW. Growth factors, matrices, and forces combine and control
stem cells. Science. 2009 Jun 26;324(5935):1673-7.
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• Xavier JR, Thakur T, Desai P, Jaiswal MK, Sears N, Cosgriff-Hernandez E, Kaunas R, Gaharwar AK.
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