Flexible Allyl-Modified Gelatin Photoclick Resin Tailored for Volumetric Bioprinting of Matrices for Soft Tissue Engineering

Volumetric bioprinting (VBP) is a light-based 3D printing platform, which recently prompted a paradigm shift for additive manufacturing (AM) techniques considering its capability to enable the fabrication of complex cell-laden geometries in tens of seconds with high spatiotemporal control and pattern accuracy. A flexible allyl-modified gelatin (gelAGE)-based photoclick resin is developed in this study to fabricate matrices with exceptionally soft polymer networks (0.2-1.0 kPa). The gelAGE-based resin formulations are designed to exploit the fast thiol-ene crosslinking in combination with a four-arm thiolated polyethylene glycol (PEG4SH) in the presence of a photoinitiator. The flexibility of the gelAGE biomaterial platform allows one to tailor its concentration spanning from 2.75% to 6% and to vary the allyl to thiol ratio without hampering the photocrosslinking efficiency. The thiol-ene crosslinking enables the production of viable cell-material constructs with a high throughput in tens of seconds. The suitability of the gelAGE-based resins is demonstrated by adipogenic differentiation of adipose-derived stromal cells (ASC) after VBP and by the printing of more fragile adipocytes as a proof-of-concept. Taken together, this study introduces a soft photoclick resin which paves the way for volumetric printing applications toward soft tissue engineering. Volumetric bioprinting (VBP) is a layer-less light-based 3D printing technique, which enables the fast production of convoluted cell-laden structures. A flexible allyl-modified gelatin-based photoclick resin is used as exceptionally soft (0.2-1.0 kPa) polymer platform for the high-throughput fabrication of adipose-derived stromal cell- and differentiated adipocyte-laden constructs in tens of seconds.image

Automated summary

This study introduces a soft photoclick resin that enables the fast production of complex cell-laden structures through volumetric bioprinting. The resin is suitable for the high-throughput fabrication of constructs containing adipose-derived stromal cells and differentiated adipocytes.