Cross-Platform Bio-Inks for 3D Printing Seamless Hydrogels as In Vivo Pressure Sensing Devices

Novel technologies in the realm of additive manufacturing have inspired researchers to explore materials that can deliver desired functionalities within a complicated design structure. The use of custom biomaterials as inks for 3D printing (bio-Inks) have been explored to curate features that are otherwise near-impossible to obtain through conventional methods where structural delamination causes device failures. Here, we look into the customization of the polymers to obtain a bio-Ink to print a seamless, single-walled hydrogel tube construct with cross-sectional diameters ranging from 100 to 3000 micrometers. An aqueous composition of gelatin and poly (ethylene glycol) with methacrylate and diacrylate group additions are investigated for their tunable properties such as swelling, soft mechanical strength, non-reactivity and biocompatibility. These hydrogels have shown an increase in swelling ratios ranging from 100% to 450% after hydration, depending on the change in the surrounding osmotic pressure. Modification of the viscoelastic and UV sensitive properties of the material yield cross-platform bio-Ink compositions that can be used to print across stereolithography (SLA), digital light processing (DLP), and direct ink extrusion technologies. Seamless hydrogel tubes 3D-printed without layers are great candidates in fabricating biomedical devices that exhibit controlled reactions triggered by changes in their microenvironment as experienced within target organs in the body. These tubes embedded with pressure sensing circuitry can dynamically monitor the pressure changes within fluid filled organs, such as the eyes to monitor glaucoma.