High molecular weight polyhydroxymethylene (PHM) has a repeat unit identical to that of low molecular weight sugar alcohols and exhibits carbohydrate‐like properties. Herein, cryogenic extrusion‐based 3D printing is combined with a phase separation in water to fabricate hierarchically porous PHM scaffolds containing interconnected macro‐, micro‐, and nanopores. As PHM is infusible and insoluble in common solvents, its precursor polyvinylene carbonate (PVCA) dissolved in dimethylsulfoxide (DMSO) is used to 3D print hierarchically porous PVCA scaffolds that are converted into PHM by hydrolysis without impairing the pore architectures. Similar to low‐temperature deposition manufacturing, the PVCA/DMSO freezes on a build platform at −78…
Three-dimensional bioprinting is an emerging technology for fabricating living 3D constructs, and it has shown great promise in tissue engineering. Bioinks are scaffold materials mixed with cells used by 3D bioprinting to form a required cell-laden structure. In this paper, a novel bioink made of gelatin methacrylamide (GelMA) and collagen (Col) doped with tyrosinase (Ty) is presented for the 3D bioprinting of living skin tissues. Ty has the dual function of being an essential bioactive compound in the skin regeneration process and also as an enzyme to facilitate the crosslink of Col and GelMA. Further, enzyme crosslinking together with photocrosslinking…
The costs associated with the treatment of medical device and surgical site infections are a major cause of concern in the global healthcare system. To prevent transmission of such infections, a prophylactic surface system that provides protracted release of antibacterial silver ions using low intensity direct electric current (LIDC; 28 μA system current at 6 V) activation has been recently developed. To ensure the safety for future in vivo studies and potential clinical applications, this study assessed the biocompatibility of the LIDC-activated interdigitated silver electrodes-based surface system; in vitro toxicity to human epidermal keratinocytes, human dermal fibroblasts, and normal human…