A novel natural polysaccharide dissolving microneedle capable of adsorbing pus to load EGCG for the treatment of acne vulgaris

Acne vulgaris is a common inflammatory skin disease associated with Propionibacterium acnes (P. acnes), with serious physical and psychological effects on patients. Conventional topical use of antibiotics is not effective due to the skin barrier and oral administration can adversely affect the intestinal flora. Microneedle is a novel type of localized drug delivery system that noninvasively breaks through the stratum corneum barrier and effectively enhances the transdermal absorption of drugs. Here, Bletilla striata polysaccharide (BSP)/Hyaluronic acid (HA) loaded Epigallocatechin gallate (EGCG) was used as the microneedle body to easily penetrate the epidermis and enhance antibacterial ability. Polyvinyl alcohol (PVA) and Diatomaceous earth (DE) are used as the microneedle backing to absorb pus and bacterial debris, prevent re-infection of bacteria and promote skin healing. Compared to traditional antibiotics, the excellent skin permeability of EGCG@BSP/HA MNs studied here can improve the efficacy and solve side effects and drug resistance. In vivo studies in mice models induced by P. acnes showed that this microneedle could effectively reduce skin swelling, inhibit bacterial growth and reduce the levels of TNF-α, IL-8 and MMP-2. In summary, this study provides an ideal antimicrobial drug delivery system for the treatment of acne vulgaris.