BACKGROUND: Three-dimensional (3D) printing using hydrogel has made great strides when it comes to mimicking 3Dartificial tissue in the medical field. However, most structures do not mimic the dynamic movement of the tissues. Withoutimitating dynamic movements, there are limitations on the extent to which the proper implementation of the tissue’s ownfunctions can be achieved.METHOD: In this study, we intend to present an approach to solving this problem using hydroxybutyl methacrylatedchitosan (HBC-MA), a photo-crosslinkable/temperature reversible chitosan polymer. In addition, stereolithography-3D(SLA-3D) printing technology was used, which is more likely to mimic the complex microstructure. As a control, a 3Dstructure made with pristine poly(ethylene glycol) dimethacrylate (PEG-DMA) was created, and a 4D structure wasprepared by adding HBC-MA to poly(ethylene glycol) dimethacrylate (PEG-DMAP) resin. RESULTS: HBC-MA caused the expansion of water into the polymer matrix at low temperature, and the 4D structureresulted in expansion of the polymer volume, generating dynamic movement due to the expansion of water. Conversely, asthe temperature rose, deswelling occurred, followed by a decrease in the volume, showing a shape memory property ofreturning to the existing structure. Morphological, swelling, and mechanical analysis further confirmed the principle ofdynamic movement. In addition, parameters were provided through calculation of the bending ratio angle (h). CONCLUSION Through this, it is suggested that HBC-MA can be applied as a core polymer for SLA-4D printing, andhas high potential for realizing the dynamic movement of tissue.

BACKGROUND: Three-dimensional (3D) printing using hydrogel has made great strides when it comes to mimicking 3Dartificial tissue in the medical field. However, most structures do not mimic the dynamic movement of the tissues. Withoutimitating dynamic movements, there are limitations on the extent to which the proper implementation of the tissue’s ownfunctions can be achieved.METHOD: In this study, we intend to present an approach to solving this problem using hydroxybutyl methacrylatedchitosan (HBC-MA), a photo-crosslinkable/temperature reversible chitosan polymer. In addition, stereolithography-3D(SLA-3D) printing technology was used, which is more likely to mimic the complex microstructure. As a control, a 3Dstructure made with pristine poly(ethylene glycol) dimethacrylate (PEG-DMA) was created, and a 4D structure wasprepared by adding HBC-MA to poly(ethylene glycol) dimethacrylate (PEG-DMAP) resin. RESULTS: HBC-MA caused the expansion of water into the polymer matrix at low temperature, and the 4D structureresulted in expansion of the polymer volume, generating dynamic movement due to the expansion of water. Conversely, asthe temperature rose, deswelling occurred, followed by a decrease in the volume, showing a shape memory property ofreturning to the existing structure. Morphological, swelling, and mechanical analysis further confirmed the principle ofdynamic movement. In addition, parameters were provided through calculation of the bending ratio angle (h). CONCLUSION Through this, it is suggested that HBC-MA can be applied as a core polymer for SLA-4D printing, andhas high potential for realizing the dynamic movement of tissue.