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International Journal of Bioprinting Bioprinted tissue-on-a-chip in drug screening

neuroblastoma tissue on the chip. The bioink was printed on Several issues need to be addressed to obtain predictive
the central groove, and the above procedures were repeated and cogent results from microarrays: (ⅰ) The appropriate
after printing vessels with sacrificial bioink (Pluronic). In quantity of cells required in microdroplets needs to be
order to distribute the ECs evenly on the channel walls, an determined. (ⅱ) Consistent culture conditions should be
orbital oscillator was integrated to form the vascular wall. maintained in different microdroplets. (ⅲ) Taking high
The fully automated process eliminated the manual steps throughput as the prerequisite, further development of
of the traditional tumor-on-a-chip and was expected to structural complexity is necessary.
enable high-throughput screening (Figure 6E).
5. Prospects in precision medicine
Zhang et al. printed the vessel model with branches
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in GelMA hydrogel, and inoculated erythrocytes following The 3D-bioprinted microfluidic model can be used not
perfusion with whole blood for a while. The coagulant was only in preclinical stages but also in the evaluation of drug
added in one branch to enable the thrombus formation therapy effects on different patients. To provide effective
to ensure perfusability of another branch. The addition treatment options for different patients, it is important
of thrombolytic agents and co-culture with fibroblasts for the model to incorporate more characteristics from
confirmed the potential application in pathological patient microenvironments. Drug treatment can be
tailored based on specific pathogenesis and dosage for
models, including thrombus, thrombolysis, fibrosis, and each person. The inaccurately predictive results of animal
related drug studies. models, the gap between animal models and humans, and

The disease-on-a-chip will no longer be limited to the high experimental cost promote the advancement
reproducing the lesion locations. Taking the artificial of human-derived in vitro models using emerging
tumor model as an example, the interaction between tumor manufacturing technologies. Precision medicine utilizes
and vessels that plays a role in tumor metastasis gives pathological information such as genetic materials to
impetus to developing a vascularized tumor-on-a-chip, distinguish specific patients from other patients with
which enhances physiological correlation and exhibits the similar disease characteristics and match them with
potential to screen drugs for inhibiting angiogenesis and personalized treatment options. These individual-based
tumor metastasis. treatments result in lower dosages, fewer side effects,
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and less toxicity. Personalized human-derived in vitro
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4.3. 3D-bioprinted microfluidic arrays models are the perfect solution for the implementation
Microfluidic arrays with multiple reaction sites require of personalized medicine. The research of patient-derived
repeated manual operations. Nevertheless, inkjet-based models, multi-organ chips, and drug therapy lays a solid
bioprinting provides a solution that fully automates both foundation for precision medicine.
cell inoculation and model formation, thereby realizing 5.1. Patient-oriented models
high-throughput analysis.
In the fabrication of bioprinted OOCs, ordinary
Microarrays have ten-fold reaction sites generated by functional hydrogels and animal-derived bioinks are
pre-mixed bioinks. This program realizes high-throughput replaced by human-derived bioinks, such as dECM
drug screening and minimal reagent consumption. extracted from human tissues. The quality of prepared
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Multiple microarrays in which an ejected droplet is a bioink is critical for the maturation of the models. When
reaction site are always incorporated with automated the bioink exhibits significant individual differences, it
3D inkjet-based bioprinting. Inkjet-based bioprinting contains individual genetic information and expresses
is effective in printing droplets with cells, whereas functional protein. As a result, the patient-derived models
the resulting bioprinted constructs are simple at the constructed from such bioink have more individual
cellular level. specificity. Consequently, optimal treatment can be
identified to achieve the goal of precision medicine.
In this study, 400 single-cell microreactors were created Moreover, the cultured cells could be substituted by tissues
using inkjet bioprinting on a microfluidic chip after the excised from each patient. Constructs from patients with
printing parameters were optimized. However, each the same disease are fabricated to explore the individual
microreactor contained cancer cells with weak migration variability according to their drug response. Although
ability, and the reaction in each microreactor was unable to patient-derived chips may not fully replicate genetic
recapitulate that in organs. Ultimately, paclitaxel at varying information, the parental tumor phenotype and the
concentrations, which was found to be dose-dependent, heterogeneity that decide the variation of drug resistance
was applied on this chip. are retained. As a result, the models have high accuracy
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Volume 10 Issue 3 (2024) 188 doi: 10.36922/ijb.1951