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International Journal of Bioprinting Medical regenerative in situ bioprinting

Bioprinting is increasingly demanded due to conditions tomography (CT), before printing and transplantation to
such as osteosarcoma, osteoporosis, and skin the wound site, but the time-consuming nature of MRI
7,8
5,6
burns. 9–11 Given the complex hierarchical architectures or CT scanning makes this approach challenging for
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of human organs and the individual differences among time-sensitive clinical cases ; (ii) the printed scaffolds
patients, conventional tissue engineering strategies fail to may deform or contract after implantation, making it
2
fabricate scaffolds with controlled surface chemistry and challenging to precisely match the defects ; (iii) before
complex microstructure. 12,13 Bioprinting can construct surgical implantation, the scaffold requires in vitro
24
artificial tissue grafts with precise cell and regenerative maturation that lasts several weeks. Hence, it is necessary
factor placements, overcoming the limitations of donor to overcome these barriers in 3D bioprinting to meet the
availability. Bioprinting is also widely used to create tissue needs of emergency clinical applications. 25
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models for drug testing 15–18 and disease modeling. 19–22 Conversely, in situ, bioprinting, introduced in 2007 as
However, there are still limitations that hinder its an emerging strategy for clinical translation of bioprinting,
development: (i) conventional bioprinting strategies has recently gained traction. 26,27 This technology, also called
require a computer-aided design (CAD) model, generated intraoperative bioprinting, directly prints biomaterials
by magnetic resonance imaging (MRI) or X-ray computed inside tissue defects. 28,29 In situ bioprinting bypasses in

Figure 1. Schematic diagrams of (A) robotic-assisted in situ bioprinting system (RASBS) and (B) handheld in situ bioprinting system (HISBS). Adapted,
with permission, from Levin et al. (A) and Cheng et al. (B).
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Volume 10 Issue 5 (2024) 48 doi: 10.36922/ijb.3366