Microgels for Cell Delivery in Tissue Engineering and Regenerative Medicine

Microgels prepared from natural or synthetic hydrogel materials have aroused extensive attention as multifunctional cells or drug carriers,that are promising for tissue engineering and regenerative medicine.Microgels can also be aggregated into microporous scaffolds,promoting cell infiltration and proliferation for tissue repair.This review gives an overview of recent developments in the fabrication techniques and applications of microgels.A series of conventional and novel strategies including emulsification,microfluidic,lithography,electrospray,centrifugation,gas-shearing,three-dimensional bioprinting,etc.are discussed in depth.The characteristics and applications of microgels and microgel-based scaffolds for cell culture and delivery are elaborated with an emphasis on the advantages of these carriers in cell therapy.Additionally,we expound on the ongoing and foreseeable applications and current limitations of microgels and their aggregate in the field of biomedical engineering.Through stimulating innovative ideas,the present review paves new avenues for expanding the application of microgels in cell delivery techniques.

A 3D Bioprinted Gut Anaerobic Model for Studying Bacteria–Host Interactions

The role of the human intestinal tract in host–microbe interactions has been highlighted in recent years.Several 3-dimensional(3D)models have been developed to reproduce the physiological characteristics of the human gut and to investigate the function of the gut microbiota.One challenge for 3D models is to recapitulate the low oxygen concentrations in the intestinal lumen.Moreover,most earlier 3D culture systems used a membrane to physically separate bacteria from the intestinal epithelium,which has sometimes made the studies of bacteria adhering to or invading cells less feasible.We report the establishment of a 3D gut epithelium model and cultured it at high cell viability under an anaerobic condition.We further cocultured intestinal bacteria including both commensal and pathogen directly with epithelial cells in the established 3D model under the anaerobic condition.We subsequently compared the gene expression differences of aerobic and anaerobic conditions for cell and bacterial growth via dual RNA sequencing.Our study provides a physiologically relevant 3D gut epithelium model that mimics the anaerobic condition in the intestinal lumen and supplies a powerful system for future in-depth gut–microbe interactional investigations.