Extrusion-based bioprinting is a powerful tool for fabricating complex cell-laden constructs. Embedded ink writing (EIW) is an extrusion-based printing technique wherein a nozzle embedded into a support bath writes continuous filaments. Because it allows for low-viscosity inks, EIW is particularly useful for bioprinting. One of the largest challenges in extrusion-based bioprinting is limiting the damage that cells experience inside the nozzle. Longer shear stress durations and higher shear stress magnitudes lead to more damage. Shape fidelity is also critical for bioprinting. Filaments in EIW can exhibit defects such as sharp edges and large aspect ratios, which can lead to porosity, surface roughness, and poor mechanical properties in the final part. We use numerical computational fluid dynamics simulations in OpenFOAM to evaluate whether common shear stress mitigation techniques improve cell viability without causing shape defects. Critically, we find that using a conical nozzle, increasing the nozzle diameter, decreasing the print speed, and decreasing the ink viscosity can improve the viability of stress magnitude-sensitive cells, but using a conical nozzle, increasing the nozzle length, and decreasing the print speed can increase damage in stress duration-sensitive cells. Additionally, using a conical nozzle or a larger nozzle can lead to larger shape defects in printed filaments. Material selection and printing parameter selection in embedded bioprinting should take into account allowable shape defects, allowable cell damage, and cell type.

1.
I. T.
Ozbolat
and
M.
Hospodiuk
, “
Current advances and future perspectives in extrusion-based bioprinting
,”
Biomaterials
76
,
321
343
(
2016
).
2.
C. S.
O'Bryan
,
T.
Bhattacharjee
,
S. R.
Niemi
,
S.
Balachandar
,
N.
Baldwin
,
S. T.
Ellison
,
C. R.
Taylor
,
W. G.
Sawyer
, and
T. E.
Angelini
, “
Three-dimensional printing with sacrificial materials for soft matter manufacturing
,”
MRS Bull.
42
,
571
577
(
2017
).
3.
L.
Ning
and
X.
Chen
, “
A brief review of extrusion–based tissue scaffold bio–printing
,”
Biotechnol. J.
12
,
1600671
(
2017
).
4.
E.
Mirdamadi
,
N.
Muselimyan
,
P.
Koti
,
H.
Asfour
, and
N.
Sarvazyan
, “
Agarose slurry as a support medium for bioprinting and culturing freestanding cell-laden hydrogel constructs
,”
3D Print. Addit. Manuf.
6
,
158
164
(
2019
).
5.
S.
Boularaoui
,
G.
Al Hussein
,
K. A.
Khan
,
N.
Christoforou
, and
C.
Stefanini
, “
An overview of extrusion-based bioprinting with a focus on induced shear stress and its effect on cell viability
,”
Bioprinting
20
,
e00093
(
2020
).
6.
A.
Blaeser
,
D. F.
Duarte Campos
,
U.
Puster
,
W.
Richtering
,
M. M.
Stevens
, and
H.
Fischer
, “
Controlling shear stress in 3D bioprinting is a key factor to balance printing resolution and stem cell integrity
,”
Adv. Healthcare Mater.
5
,
326
333
(
2016
).
7.
L.
Ning
,
A.
Guillemot
,
J.
Zhao
,
G.
Kipouros
, and
X.
Chen
, “
Influence of flow behavior of alginate-cell suspensions on cell viability and proliferation
,”
Tissue Eng., Part C
22
,
652
662
(
2016
).
8.
M.
Li
,
X.
Tian
,
N.
Zhu
,
D. J.
Schreyer
, and
X.
Chen
, “
Modeling process-induced cell damage in the biodispensing process
,”
Tissue Eng., Part C
16
,
533
542
(
2010
).
9.
M.
Li
,
X.
Tian
,
D. J.
Schreyer
, and
X.
Chen
, “
Effect of needle geometry on flow rate and cell damage in the dispensing–based biofabrication process
,”
AIChE J.
27
,
1777
1784
(
2011
).
10.
R.
Paul
,
J.
Apel
,
S.
Klaus
,
F.
Schügner
,
P.
Schwindke
, and
H.
Reul
, “
Shear stress related blood damage in laminar Couette flow
,”
Artif. Organs
27
,
517
529
(
2003
).
11.
L.
Ning
,
N.
Betancourt
,
D. J.
Schreyer
, and
X.
Chen
, “
Characterization of cell damage and proliferative ability during and after bioprinting
,”
ACS Biomater. Sci. Eng.
4
,
3906
3918
(
2018
).
12.
J.
Emmermacher
,
D.
Spura
,
J.
Cziommer
,
D.
Kilian
,
T.
Wollborn
,
U.
Fritsching
,
J.
Steingroewer
,
T.
Walther
,
M.
Gelinsky
, and
A.
Lode
, “
Engineering considerations on extrusion-based bioprinting: Interactions of material behavior, mechanical forces and cells in the printing needle
,”
Biofabrication
12
,
025022
(
2020
).
13.
G.
Gao
,
B. S.
Kim
,
J.
Jang
, and
D.-W.
Cho
, “
Recent strategies in extrusion-based three-dimensional cell printing toward organ biofabrication
,”
ACS Biomater. Sci. Eng.
5
,
1150
1169
(
2019
).
14.
T.
Billiet
,
E.
Gevaert
,
T.
De Schryver
,
M.
Cornelissen
, and
P.
Dubruel
, “
The 3D printing of gelatin methacrylamide cell-laden tissue-engineered constructs with high cell viability
,”
Biomaterials
35
,
49
62
(
2014
).
15.
R.
Chang
,
J.
Nam
, and
W.
Sun
, “
Effects of dispensing pressure and nozzle diameter on cell survival from solid freeform fabrication-based direct cell writing
,”
Tissue Eng., Part A
14
,
41
48
(
2008
).
16.
N.
Chen
,
K.
Zhu
,
Y. S.
Zhang
,
S.
Yan
,
T.
Pan
,
M.
Abudupataer
,
G.
Yu
,
M. F.
Alam
,
L.
Wang
,
X.
Sun
,
Y.
Yu
,
C.
Wang
, and
W.
Zhang
, “
Hydrogel bioink with multilayered interfaces improves dispersibility of encapsulated cells in extrusion bioprinting
,”
ACS Appl. Mater. Interfaces
11
,
30585
30595
(
2019
).
17.
A. M.
Compaan
,
K.
Song
,
W.
Chai
, and
Y.
Huang
, “
Cross-linkable microgel composite matrix bath for embedded bioprinting of perfusable tissue constructs and sculpting of solid objects
,”
ACS Appl. Mater. Interfaces
12
,
7855
(
2020
).
18.
S. R.
Moxon
,
M. E.
Cooke
,
S. C.
Cox
,
M.
Snow
,
L.
Jeys
,
S. W.
Jones
,
A. M.
Smith
, and
L. M.
Grover
, “
Suspended manufacture of biological structures
,”
Adv. Mater.
29
,
1605594
(
2017
).
19.
L.
Ning
,
R.
Mehta
,
C.
Cao
,
A.
Theus
,
M.
Tomov
,
N.
Zhu
,
E. R.
Weeks
,
H.
Bauser-Heaton
, and
V.
Serpooshan
, “
Embedded 3D bioprinting of gelatin methacryloyl-based constructs with highly tunable structural fidelity
,”
ACS Appl. Mater. Interfaces
12
,
44563
44577
(
2020
).
20.
L. M.
Friedrich
and
J. E.
Seppala
, “
Simulated filament shapes in embedded 3D printing
,”
Soft Matter
17
,
8027
(
2021
).
21.
A.
Shapira
,
N.
Noor
,
H.
Oved
, and
T.
Dvir
, “
Transparent support media for high resolution 3D printing of volumetric cell-containing ECM structures
,”
Biomed. Mater.
15
,
045018
(
2020
).
22.
H.
Ding
and
R.
Chang
, “
Printability study of bioprinted tubular structures using liquid hydrogel precursors in a support bath
,”
Appl. Sci.
8
,
403
(
2018
).
23.
T.
Calais
,
N. D.
Sanandiya
,
S.
Jain
,
E. V.
Kanhere
,
S.
Kumar
,
R. C.-H.
Yeow
, and
P.
Valdivia y Alvarado
, “
Freeform liquid 3D printing of soft functional components for soft robotics
,”
ACS Appl. Mater. Interfaces
14
,
2301
2315
(
2022
).
24.
L. M.
Friedrich
,
R. T.
Gunther
, and
J. E.
Seppala
, “
Suppression of filament defects in embedded 3D printing
,”
ACS Appl. Mater. Interfaces
14
,
32561
(
2022
).
25.
T.
Bhattacharjee
,
S. M.
Zehnder
,
K. G.
Rowe
,
S.
Jain
,
R. M.
Nixon
,
W. G.
Sawyer
, and
T. E.
Angelini
, “
Writing in the granular gel medium
,”
Sci. Adv.
1
,
e1500655
(
2015
).
26.
Y.
Jin
,
A.
Compaan
,
W.
Chai
, and
Y.
Huang
, “
Functional nanoclay suspension for printing-then-solidification of liquid materials
,”
ACS Appl. Mater. Interfaces
9
,
20057
20066
(
2017
).
27.
T. J.
Hinton
,
Q.
Jallerat
,
R. N.
Palchesko
,
J. H.
Park
,
M. S.
Grodzicki
,
H.-J.
Shue
,
M. H.
Ramadan
,
A. R.
Hudson
, and
A. W.
Feinberg
, “
Three-dimensional printing of complex biological structures by freeform reversible embedding of suspended hydrogels
,”
Sci. Adv.
1
,
e1500758
(
2015
).
28.
M. E.
Cooke
and
D. H.
Rosenzweig
, “
The rheology of direct and suspended extrusion bioprinting
,”
APL Bioeng.
5
,
011502
(
2021
).
29.
M.
Jalaal
,
G.
Cottrell
,
N.
Balmforth
, and
B.
Stoeber
, “
On the rheology of Pluronic F127 aqueous solutions
,”
J. Rheol.
61
,
139
146
(
2017
).
30.
G. P.
Roberts
and
H. A.
Barnes
, “
New measurements of the flow-curves for Carbopol dispersion without slip artefacts
,”
Rheol. Acta
40
,
499
503
(
2001
).
31.
W.
Feng
,
Y.
Chai
,
J.
Forth
,
P. D.
Ashby
,
T. P.
Russell
, and
B. A.
Helms
, “
Harnessing liquid-in-liquid printing and micropatterned substrates to fabricate three-dimensional all-liquid fluidic devices
,”
Nat. Commun.
10
,
1095
(
2019
).
32.
R.
Xu
,
T.
Liu
,
H.
Sun
,
B.
Wang
,
S.
Shi
, and
T. P.
Russell
, “
Interfacial assembly and jamming of polyelectrolyte surfactants: A simple route to print liquids in low-viscosity solution
,”
ACS Appl. Mater. Interfaces
12
,
18116
18122
(
2020
).
33.
C.
Poon
, “
Measuring the density and viscosity of culture media for optimized computational fluid dynamics analysis of in vitro devices
,”
J. Mech. Behav. Biomed. Mater.
126
,
105024
(
2022
).
34.
OpenFOAM v8 (
The OpenFOAM Foundation,
2020
).
35.
Certain commercial equipment, instruments, or materials are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose.
36.
G.
Van Rossum
and
F. L.
Drake
,
Python 3 Reference Manual
(
CreateSpace, Scotts Valley
,
CA
,
2009
).
37.
L. M.
Friedrich
,
R. T.
Gunther
, and
J. E.
Seppala
(
2022
). “Python tools for OpenFOAM simulations of filament shapes in embedded 3D printing,”
NIST Public Data Repository
, .
38.
J.
Ahrens
,
B.
Geveci
, and
C.
Law
,
ParaView: An End-User Tool for Large Data Visualization
(
Elsevier
,
2005
).
39.
L. M.
Friedrich
,
R. T.
Gunther
, and
J. E.
Seppala
(
2022
), “OpenFOAM simulations of stress mitigation strategies in embedded 3D bioprinting,”
NIST Public Data Repository
, .
40.
J.
Kajtez
,
M. F.
Wessler
,
M.
Birtele
,
F. R.
Khorasgani
,
D. R.
Ottosson
,
A.
Heiskanen
,
T.
Kamperman
,
J.
Leijten
,
A.
Martínez-Serrano
,
N. B.
Larsen
,
T. E.
Angelini
,
M.
Parmar
,
J. U.
Lind
, and
J.
Emnéus
, “
Embedded 3D printing in self-healing annealable composites for functional patterning of human neural constructs
,”
Adv. Sci.
2022
,
2201392
.
41.
S. M.
Damián
and
N.
Nigro
, “
An extended mixture model for the simultaneous treatment of small-scale and large-scale interfaces
,”
Int. J. Numer. Methods Fluids
75
,
547
574
(
2014
).
42.
S. M.
Damián
, “
An extended mixture model for the simultaneous treatment of small-scale and large-scale interfaces
,” Ph.D. thesis (
Universidad Nacional del Litoral
,
2013
).
43.
S. S.
Deshpande
,
L.
Anumolu
, and
M. F.
Trujillo
, “
Evaluating the performance of the two-phase flow solver interFoam
,”
Comput. Sci. Dis.
5
,
014016
(
2012
).
44.
T.
Holtzmann
,
Mathematics, Numerics, Derivations, and OpenFOAM
(Holzmann CFD,
2019
).
45.
R.
Burdis
and
D. J.
Kelly
, “
3D bioprinting hardware
,” in
Polymer-based Additive Manufacturing
(
Springer
,
2019
), pp.
161
186
.
46.
S. M.
Hull
,
L. G.
Brunel
, and
S. C.
Heilshorn
, “
3D bioprinting of cell-laden hydrogels for improved biological functionality
,”
Adv. Mater.
34
,
2103691
(
2022
).
47.
M.
Nooranidoost
,
D.
Izbassarov
,
S.
Tasoglu
, and
M.
Muradoglu
, “
A computational study of droplet-based bioprinting: Effects of viscoelasticity
,”
Phys. Fluids
31
,
081901
(
2019
).
48.
L.
Friedrich
,
R.
Collino
,
T.
Ray
, and
M.
Begley
, “
Acoustic control of microstructures during direct ink writing of two-phase materials
,”
Sens. Actuators, A
268
,
213
221
(
2017
).
49.
Y.
Sriphutkiat
,
S.
Kasetsirikul
,
D.
Ketpun
, and
Y.
Zhou
, “
Cell alignment and accumulation using acoustic nozzle for bioprinting
,”
Sci. Rep.
9
,
17774
(
2019
).
50.
D.
Leighton
and
A.
Acrivos
, “
The shear-induced migration of particles in concentrated suspensions
,”
J. Fluid Mech.
181
,
415
439
(
1987
).

Supplementary Material

You do not currently have access to this content.