Sustainable Electrospun Poly(l-lactic acid) Fibers for Controlled Release of the Mosquito-Repellent Ethyl Butylacetylaminopropionate (IR3535)

Fibers composed of poly(l-lactic acid) (PLLA)and themosquito-repellent ethyl butylacetylaminopropionate (IR3535) wereprepared by solution electrospinning. Defect-free and uniform monoaxialfibers with a diameter of the order of magnitude of 1 & mu;m wereobtained. Thermogravimetric analyses showed that it is possible toincorporate more than 40 m% of IR3535 into the PLLA fibers. Thermaland structural characterization indicated that IR3535 facilitatesthe crystallization of PLLA and formation of orthorhombic & alpha;-crystalsduring electrospinning. IR3535 has a plasticizing effect on PLLA,as detected by the decrease in the glass transition temperature. Therelease of IR3535 from PLLA/IR3535 fibers to the environment was quantifiedby thermogravimetric analysis at different temperatures ranging from60 to 100 & DEG;C, suggesting rather slow evaporation of the repellent,with a time constant of few days at body temperature. The observedresults indicate a possible use of electrospun PLLA/IR3535 fiber matsas part of a long-lasting repellent-delivery system and applicationin the field of combating diseases caused by mosquito bites.