Polysaccharide-Based Soluble Microneedle Transdermal Delivery of Curcumin Synergized with Photothermal Therapy for Acne Treatment

Acne is a chronic inflammatory skin disease driven primarily by Propionibacterium acnes (P. acnes) colonization in hair follicles, which can progress from mild to severe forms and result in permanent scarring if left untreated. To resolve this problem, this study developed a polysaccharide-based light–heat-mediated soluble microneedle system for the transdermal delivery of antiacne agents encapsulated in mesoporous polydopamine nanoparticles (MPDA) for the effective treatment of acne vulgaris. A multifunctional microneedle (Cur-MPDA + Cur@HA/FPS MNs) based on hyaluronic acid and fucoidan (FPS) was prepared and functionalized by curcumin-loaded mesoporous polydopamine nanoparticles (Cur-MPDA) and backing containing curcumin, endowing it with a photothermal response, sustained-release, robust reactive oxygen species scavenging capacity, and antibacterial multiple properties. The microneedle system exhibited good mechanical strength and rapid tip dissolution within 2 min upon insertion. It demonstrated a strong antibacterial activity with 70.9% against P. acnes, good biocompatibility, and acne inflammation reduction. Most notably, when combined with NIR irradiation, the microneedle system achieved an outstanding antibacterial ratio of 99.4% against P. acnes and restored skin thickness to near-normal levels. Collectively, this microneedle system demonstrates a highly effective and patient-friendly approach to acne vulgaris treatment.