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International Journal of Bioprinting 3D-printed bioelectronic devices

cellular activity. In this context, bioelectric scaffolds that micropillar electrodes and elastic microwires to record
can apply physiological ES to cells have been developed electrophysiological signals and contractile functions.
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to investigate the underlying mechanisms of ES-mediated The DIW-based 3D printing method has allowed the
cellular responses and induce tissue regeneration in vitro fabrication of high-aspect-ratio micropillars by tuning
or in vivo. the height, electrochemical properties, and elasticity of
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For instance, a DIW 3D-printed PLA scaffold the electrodes.
containing bismuth ferrite (BFO) nanoparticles was 5. Conclusion and future perspectives
developed to construct a 3D cellular environment for
neural tissue engineering (Figure 6A). In this scaffold, 3D printing has emerged as a state-of-the-art manufacturing
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the physiological level of ES applied to stem cells induced technology in the biomedical field, offering patient-specific
cell alignment toward BFO lines. Similarly, a conductive customization through low-cost and efficient fabrication
and biodegradable scaffold made of polycaprolactone processes. 148–151 Diverse printing techniques and materials
and MWCNTs was 3D-printed using DIW for bone have enabled the construction of functional devices
tissue regeneration (Figure 6B). Following scaffold tailored to individual needs. These bioelectronic devices
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implantation at the bone defect site, exogenous ES was can be seamlessly integrated into biological systems and
applied using a transcutaneous electrical stimulator. The applied to patient care. However, challenges persist as
combination of conductive PCL/MWCNT scaffolds with 3D-printed models strive to achieve an ideal match with
ES promotes angiogenesis and mineralized bone tissue the human body in terms of mechanical, chemical, and
formation. functional aspects. In this section, the current challenges in
3D-printed applications in medicine and future directions
Various types of sensors have been integrated into tissue
engineering platforms to monitor biological functions in are discussed.
real time. An instrumented cardiac microphysiological For practical application of wearable and implantable
device incorporating soft strain gauge sensors, electrical devices, there are several key considerations, including
interconnects, and eight independent cell culture wells was biocompatibility, long-term stability, sensitivity,
fabricated using DIW multi-material 3D printing. This and measurement accuracy. The device should be
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device enabled the measurement of contraction strength biocompatible to avoid chronic immune responses and to
and beat rate in drug–dose response studies within an in ensure stable physiological biosignal monitoring during
vitro environment over a long testing period. Another long-term biointegration. Devices with high mechanical
cardiac microphysiological platform combined 3D-printed flexibility and stretchability should be designed for stable

Figure 6. 3D-printed tissue-engineered scaffolds. (A) 3D-printed scaffolds for stimulating human adipose-derived mesenchymal stem cells. Reproduced
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with permission from Wiley . Copyright © 2021 Wiley. (B) 3D-printed polycaprolactone (PCL)/multi-walled carbon nanotubes (MWCNTs) scaffolds with
electrical stimulation (ES) for bone tissue regeneration. Reproduced with permission from Springer Nature. Copyright © 2021 Springer.
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Volume 10 Issue 6 (2024) 105 doi: 10.36922/ijb.4139