Development of Bioimplants with 2D, 3D, and 4D Additive Manufacturing Materials

Over the past 30 years,additive manufacturing(AM)has developed rapidly and has demonstrated great potential in biomedical applications.AM is a materials-oriented manufacturing technology,since the solidification mechanism,architecture resolution,post-treatment process,and functional application are based on the materials to be printed.However,3D printable materials are still quite limited for the fabrication of bioimplants.In this work.2D/3D AM materials for bioimplants are reviewed.Furthermore,inspired by Tai Chi,a simple yet novel soft/rigid hybrid 4D AM concept is advanced to develop complex and dynamic biological structures in the human body based on 4D printing hybrid ceramic precursor/ceramic materials that were previously developed by our group.With the development of multi-material printing technology,the development of bioimplants and soft/rigid hybrid biological structures with 2D/3D/4D AM materials can be anticipated.

Wet-spinning fabrication of shear-patterned alginate hydrogel microfibers and the guidance of cell alignment

Native tissue is naturally comprised of highly-ordered cell-matrix assemblies in a multi-hierarchical way,and the nano/submicron alignment of fibrous matrix is found to be significant in supporting cellular functionalization.In this study,a self-designed wet-spinning device appended with a rotary receiving pool was used to continuously produce shear-patterned hydrogel microfibers with aligned submicron topography.The process that the flow-induced shear force reshapes the surface of hydrogel fiber into aligned submicron topography was systematically analysed.Afterwards,the effect of fiber topography on cellular longitudinal spread and elongation was investigated by culturing rat neuron-like PC12 cells and human osteosarcoma MG63 cells with the spun hydrogel microfibers,respectively.The results suggested that the stronger shear flow force would lead to more distinct aligned submicron topography on fiber surface,which could induce cell orientation along with fiber axis and therefore form the cell-matrix dual-alignment.Finally,a multi-hierarchical tissue-like structure constructed by dual-oriented cell-matrix assemblies was fabricated based on this wet-spinning method.This work is believed to be a potentially novel biofabrication scheme for bottom-up constructing of engineered linear tissue,such as nerve bundle,cortical bone,muscle and hepatic cord.