Engineering Immune-Competent Hair Follicle Microphysiological Systems: From Organoid Assembly to Dynamic Immune Modelling

This review discusses the advancement of hair follicle organoids towards immune-competent hair follicle microphysiological systems (HF-MPS), which aim to better replicate the immune, vascular, neural, and dynamic regulatory features of native hair follicles. These systems are particularly important for studying immune-mediated hair disorders like alopecia areata, where immune privilege collapse and inflammatory infiltration are key issues. The review outlines the structural basis of HF engineering and defines immune competence as maintaining immune privilege, regulating hair follicle cycling and regeneration, and managing inflammatory injury. It also explores engineering strategies such as local immune microenvironment control and dynamic perfusion. The applications of HF-MPS in disease modeling, drug evaluation, and regenerative medicine are discussed, emphasizing that these systems are evolving platforms rather than complete replacements for existing models.