Tissue engineering ECM-enriched controllable vascularized human microtissue for hair regenerative medicine using a biomimetic developmental approach

•Layer-by-layer (LbL) self-assembly to construct nanoscale biomimetic ECM.•Ca2+ as a cross-linking agent to make size controllable dermal papilla (DP) spheroids.•Tissue engineering controllable human microtissue rich in ECM and vessels.•Vascularization prevents hypoxia-induced necrosis and functions in connection with host vessels.•Biomimetic ECM and vascularization triple hair induction efficiency.