Page 163 - IJB-10-1

International Journal of Bioprinting 3D-printed micro-perfused culture device

endogenous materials. The CYP3A subfamily was selected direct integration of aligned fibrous scaffold can be applied
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in this study since it contributes to the biotransformation to the device. Aligned fibrous scaffold can be applied to cells
of more than 50% of oxidatively metabolized drugs. requiring aligned ECM structure, such as smooth muscle
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From the gene expression studies in Figure 8, the albumin cells, tendons, bones and skeletal muscles. However, the
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gene expression was found to be significantly higher for current challenge in this process is the limitation of device
MPC platform compared to TCPS and static culture. This sizes that can be fabricated since the size cannot go beyond
significant upregulation indicates that the perfused culture the SLA build plate (current build area for printer is 119 ×
is favorable for the culturing of hepatocytes since the liver is 67 mm). Mass production is also limited on the SLA printer
also a highly perfused environment. Similarly, significant and hence would need equipment modifications.
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upregulation of CYP3A7 has been observed for perfused
culture (~3.4-fold), while the static culture did not exhibit 5. Conclusion
any enhancement. The expression of CYP3A7 was found A 3D-printed MPC device embedded with a 3D fibrous
to be significantly lower for the static culture compared to scaffold was demonstrated through the SLA printing process.
the other substrates. The lack of CYP3A4 function could be The fibrous and porous nature of the embedded scaffold
an indication of poor liver function on a static platform. 70,71 was used in this study to recapitulate the structure aspect of
There is no statistical difference between TCPS and MPC the ECM of a native tissue. This is the first instance where
platform for CYP3A4 enzyme. A further quantification a biological component in the form of a 3D miniaturized
of albumin synthesis was performed on static and MPC porous scaffold was embedded in a printed device. The model
platform. From Figure 8b, the albumin quantity at day 4 cells, Huh7.5 hepatocellular carcinoma cells, used in this
for the perfused culture had significantly higher amount study exhibited thicker cell construct on the MPC device than
of albumin secretion (~3 times). This indicates a more the static culture at day 4. In addition, the gene expression of
functional hepatocyte culture on a perfusion platform. albumin and CYP3A7 cytochrome was found to be much
Taken together, the 3D-printed MPC device has proven upregulated, ~3 times and 3.4 times, respectively, as compared
to be a more physiologically relevant platform for the to its static counterpart. In summary, the perfusion culture
maintenance of hepatocytes since the expression of albumin
and CYP3A enzymes were found to be upregulated or device reported here has proven to be a more physiologically
maintained near nominal, and albumin secretion test also relevant platform for the maintenance of hepatocytes, hence
indicated higher amount of albumin secretion for the MPC presenting the possibility of using additive manufacturing
device as compared to the static or TCPS substrate. technique (SLA) as a prototyping or manufacturing tool for
microfluidic chip with embedded functionalities.
In summary, the overall results presented in this study
are promising where micro-tissues can be formed in the Funding
presence of highly biomimicking features, e.g., the presence
of microfibrous scaffold and micro-perfusion. These This work is supported in part by the Singapore Institute
features, which are missing in conventional tissue culture of Manufacturing Technology, Agency for Science,
plates, are key to developing relevant 3D cells construct. Technology and Research (A*STAR) Singapore; MOE Tier
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The other advantage of the MPC device is the reduced 1 RG130/15 and HealthTech NTU.
consumption of cells and medium needed to develop a
thick 3D cell construct. Conventionally, 3D cell construct Conflict of interest
greater than 200 µm would require bioreactor circulation The authors declare no conflicts of interest.
of medium ; in this case, an MPC setup would need lesser
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cells and culture medium than if it were to be cultured Author contributions
in a bioreactor. Finally, the process on direct integration
of biological functional component means lesser steps Conceptualization: Yi-Chin Toh, Lay Poh Tan, Feng Lin Ng
involved in the fabrication process. The MPC device with Formal analysis: Feng Lin Ng
micro-perfusion channels would usually need secondary Investigation: Feng Lin Ng, Zhanhong Cen
bonding process if it were fabricated conventionally. In the Methodology: Feng Lin Ng, Yi-Chin Toh
current developed process, no secondary bonding process Writing – original draft: Feng Lin Ng
was needed to form closed channels and integration of Writing – review & editing: Yi-Chin Toh, Lay Poh Tan, Feng
biological component, presenting a simple fabrication Lin Ng
technique for future microfluidic chip. The developed MPC
device is highly adaptable to different cell line, for instance, Ethics approval and consent to participate
a random fibrous scaffold was used in this study, but the Not applicable.

Volume 10 Issue 1 (2024) 155 https://doi.org/10.36922/ijb.0226