Lignin-Based Nanoparticles Stabilized Pickering Emulsion for Stability Improvement and Thermal-Controlled Release of trans-Resveratrol

In this work, we designed a novel multifunctional Pickering emulsion stabilized by lignin-based nanoparticles. We utilized the industrial waste lignin to prepare thermoresponsive lignin copolymer by grafting poly(N-isopropylacrylamide) (PNIPAM) onto lignin via atom transfer radical polymerization (ATRP) and then formed self-assembled nanoparticles (AL-g-PNIPAM NPs). AL-g-PNIPAM NPs well stabilized trans-resveratrol (trans-RSV)-containing palm oil emulsion droplets in water. Thanks to the abundant UV chromophoric groups of lignin, the light stability of trans-RSV was significantly improved by the protecting of the AL-g-PNIPAM NPs layer. Moreover, the emulsion properties and release behavior strongly depend on the temperature and nanoparticles size: decreasing temperature induced deformation of AL-g-PNIPAM NPs at the interface, an increase in droplet size, and the accelerated release of trans-RSV. These results showed the great potential of this approach of a green functional lignin-based nanoparticles stabilized Pickering emulsion for storage and thermal-controlled release of light-unstable and poorly water-soluble drugs.