Thermo-responsive nanofibers for on-demand biocompound delivery platform

Abstract

A delivery platform of active compounds on demand has been developed, composed of a flexible mat of CO2-derived poly (propylene carbonate) (PPC) electrospun fibers, loaded with antioxidant cinnamon essential oil (CEO), covered with poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and poly(N-isopropylacrylamide) (PNIPAM). The PEDOT:PSS layer rendered the device electrically conductive, enabling a temperature increase upon the application of a voltage. A thin layer of PNIPAM provided a barrier against the release of the essential oil at normal storage conditions and permitted the release when the temperature of the device exceeded the lower critical solution temperature (LCST) of PNIPAM at 32 °C. Electrical transport measurements showed that a temperature higher than LCST was reached by applying 2 V, at ambient conditions, and 2.6 V at 4 °C. The contact angle of the device changed from 27° below the LCST to 64° above the LCST, demonstrating the action of PNIPAM. The release of the CEO at 20 °C (below the LCST) was negligible, while at 40 °C (above the LCST) it increased to more than 60%, resulting in radical scavenging activity of 95%. These results indicate that the proposed device can be incorporated in active food packaging.