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Priyadarshini, et al.
The biocompatibility of cells with the materials adherent CHO-K1 cells and primary hippocampal
used for 3D-printing also affects cell viability neurons . Elsewhere, bovine endothelial
[18]
and survivability. Biocompatibility could cells were immobilized on a 3D transparent
be achieved with post-printing modification microfluidic chip made from photocurable resins
and has already been reviewed earlier . The by material jetting. Owing to unknown resin
[46]
compatibility of zebrafish larvae on parts 3D- properties, the internal channels of the chip were
printed by FDM (using acrylonitrile butadiene coated with polydimethylsiloxane (PDMS) and
styrene, [ABS]) and SLA (using photocurable polystyrene, respectively. Cell adherence and
liquid resin) (Figure 1A) indicated that materials survival were favorable to PDMS, in comparison
used for FDM were less toxic compared to to polystyrene-coated, polished, and untreated
SLA evidenced by significantly lower rates of samples .
[31]
malformations. Following the UV treatment of 2.1.2 3D-printed bioreactor for cell
SLA parts, the toxicity was significantly reduced encapsulation
but not completely eliminated . In contrast,
[17]
a concurrent study indicated the potential of A pump-free perfusion device was fabricated
transparent PEG-DA-250 resin disks (printed by SLA (3D Systems Accura 60) and material
by SLA) for supporting the long-term culture of jetting (VeroClear-RGD810) for immobilizing
multicellular spheroids and maintaining their
A B viability. Even though SLA resulted in cell-
immobilizing microstructures with smoother
surfaces, good spheroid functionality, and prolonged
viability compared to PolyJet printing, the inferior
C
optical properties restricted sample visualization
by microscopy . Despite a conducive capsule
[32]
D housing for cell culture, it remains a challenging task
to entrap certain cell models with biocompatible
substrates and mandates optical transparency of
capsules due to their suitability for cell imaging.
2.1.3 3D-printed bioreactor for cell/tissue
models

Figure 1. (A) Resin disks three-dimensional In addition to providing a complex yet
(3D)-printed by fused deposition modeling, controlled ambient for cell viability and cell
stereolithography (SLA), and SLA w UV used encapsulation through spatial and temporal
for testing resin toxicity on zebrafish (40 mm control of cell growth, the increasing versatility
diameter and 4 mm height) . (B) 3D-printed of 3D-printing also enables the development
[17]
device design showing adapters for syringe- of tissue culture constructs that mimic
based pumps, channels, membrane insertion port, specific biological functions and capture cell-
and outlets. (C) The side view schematic of the tissue interactions inside the culture system.
3D-printed device to understand the channel and For example, the pathogenesis associated
fluid to flow under the membrane. The membrane with a tissue can be studied. A 3D-printed
is manually inserted into the port on top of the multichambered bioreactor fabricated with non-
device. Finally, there is an outlet to allow fluid cytotoxic Eshell 300 resin using SLA was fitted
to leave the device . (D) Potentiometric sensor- into a microfluidic base, creating tissue-specific
[34]
based biosensor chip showing inlet, outlet, and environments for the study of interactions
sensing area (20.5 mm × 4.3 mm) with attached between chondral and osseous tissues during
microfluidic channels . osteochondral differentiation [33] . This system
[45]
International Journal of Bioprinting (2020)–Volume 6, Issue 4 85