Multi-Functional Microneedles for Sustained Drug Release and Combinatory Treatment of Biofilms

Cutaneous infections involving pathogenic biofilms cannot be effectively treated by topical therapies, partially due to the resistance and the poor penetration of therapeutics. To overcome these limitations, we propose a multi-functional microneedle device that can penetrate through the stratum corneum and the extracellular polymeric substances of the biofilm for direct delivery of antimicrobial therapies. The device is fabricated by casting a Polymyxin B-loaded Polyvinyl pyrrolidone microneedle array and coating it with curcumin-loaded Poly lactic-co-glycolic acid (PLGA) particles through electrospray. The fabricated multi-functional microneedle effectively handles the conflicts of hard combinatory delivery of water-soluble drugs and oil-soluble drugs. Coupled with the less hydrophilicity of Lactide-rich PLGA, the fabricated multi-functional microneedle can also deal with moisture erosion. Our benchtop test reveals that the device has sufficient mechanical strength to pierce skin tissue. Our anti-humidity test shows that the device is moisture resistant even stored at a relative humidity of 85% for one hour. Our in vitro tests demonstrate the technical feasibility of sustained drug release and effective treatment of biofilms. Our study implies the clinical potential of using the proposed multi-functional microneedle device for combinatory treatment of biofilm-associated infections in skin