Additionally, double-layer microneedles incorporating tetracycline hydrochloride in the tip and recombinant human epidermal growth factor (rh-EGF) in the substrate have demonstrated strong antibacterial properties by rapidly releasing tetracycline to fight infections, while rh-EGF promotes angiogenesis, cell migration, and tissue regeneration, effectively reducing inflammation and accelerating wound healing [145]. Here, EGF is linked to infection.