Rational engineering of dual Drug-Formulated multifunctional microneedles to accelerate in vivo cutaneous infection treatment

Deep cutaneous infections pose formidable challenges for conventional topical treatments due to limited drug transdermal efficiency and inadequate antifungal properties. This paper presents a rational engineering approach to develop biodegradable and multifunctional microneedles (MNs) that can be easily tailored for the co-delivery of both hydrophilic and hydrophobic drugs, aimed at the combined treatment of cutaneous infections. Polymyxin B (PB)-loaded Polyvinyl pyrrolidone (PVP) is casted to fabricate microneedle array, then followed by an electrospray coating of curcumin (CUR)-loaded poly(lactic-co-glycolic acid) (PLGA) particles, affording the resultant PB-PVP-MN@CUR-PLGA. Rational coating of hydrophobic PLGA shell can significantly withstand humidity, wound exudate, and pus. Comprehensive moisture resistance tests verify the sustained mechanical strength of the multifunctional MNs, even after one hour of storage at 85% relative humidity, the multifunctional MNs still maintain the potency to effectively penetrate skin tissues. In vitro and in vivo explorations confirm sustained drug release and efficient antimicrobial treatment. The promising outcomes of current multifunctional MNs lay a solid foundation for clinical translation to treat deep skin-related diseases.