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.