Light-responsive antibacterial dissolving microneedles loaded with 5-aminolevulinic acid and silver nanoparticles for the treatment of acne.

Acne is a chronic inflammatory disease of pilosebaceous unit, which can be aggravated by hyperkeratosis of the pilosebaceous unit, excessive secretion of sebum and the proliferation of Propionibacterium acnes (P. acnes). Traditional drug treatment methods commonly exhibit drawbacks, including bacterial resistance and poor transdermal permeability, resulting in suboptimal efficacy and recurrent infections. Herein, we designed a dual drug-loaded microneedles patch to deliver ALA and silver nanoparticles for acne treatment. The comprehensive treatment of acne is achieved by utilizing the safe and efficient advantages of 5-aminolevulinic acid (ALA) photodynamic therapy (PDT), coupled with the superior antibacterial properties of silver nanoparticles. To enhance drug permeability, dissolving microneedles (DMNs) are employed for targeted and efficient drug delivery. In vitro and in vivo experiments demonstrated that DMNs loaded with both AgNPs and ALA-PDT (ALA/AgNPs@DMNs) have significant antibacterial activity, along with superior drug loading capacity and penetration. The application of ALA/AgNPs@DMNs in treating acne-affected rats alleviates excessive epidermal keratinization, effectively inhibits bacterial growth, and significantly improves acne symptoms. This suggests that the "dissolving microneedle" formulation holds promise for the treatment and management of acne.