pH-responsive Chinese herbal microneedles for acne therapy: A groundbreaking approach to skincare

Acne is a common inflammatory skin disease caused by colonization of Propionibacterium acnes (P. acnes), which causes physical and psychological effects on the patients. The delivery of active ingredients in ointments for the treatment of acne is often limited by the need to cross the stratum corneum and capillaries to reach the infected surface, resulting in poor bactericidal efficacy. Here, we have successfully developed a pH-responsive microneedle patch based on the Schiff base, which synergistically combines Sodium houttuyfonat (SH) with N, O-carboxymethylchitosan (NOCC). The patch demonstrates exceptional biocompatibility, mechanical properties and on-demand release performance through ratio optimization. Drug release study in vitro demonstrated its pH-responsive properties and controlled drug release capability to eliminate P. acnes effectively. In acne mice model (Balb/c), SH-NOCC enhanced anti-inflammatory effects and acne elimination capabilities through the NF-κB/NLRP3 signaling pathway. Together, these results indicated that SH-MN could be a potential candidate for anti-acne treatment.