Stimuli-Responsive WS2 Nanosheets as Nanocarriers for Controlled Erlotinib Release and In Vitro Drug Delivery Evaluation

Abstract

In this work, tungsten disulfide nanosheets were modified via a two-step polymer grafting method. First, poly (N-isopropylacrylamide-co-allyl alcohol) was attached to the surface, followed by xanthation using carbon disulfide in the presence of KOH, subsequent benzylation with benzyl chloride, grafting of allyl glycidyl ether, and coupling of 2-amino-5-hydroxybenzoic acid to improve stability and stimuli-responsiveness. We characterized the final product with Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy with energy-dispersive X-ray elemental analysis and thermogravimetric analysis. We tested different conditions to see how they affect erlotinib adsorption, and found the best adsorption capacity at pH 6. In vitro release experiments showed that the drug comes out much faster at higher temperature (especially 45°C) and in acidic conditions (pH 5.6), which is similar to the tumor environment. For adsorption behavior, the Langmuir isotherm model gave the best fit (R² = 0.9901), meaning the drug forms a single layer on uniform sites. The kinetics followed the pseudo-second-order model (R² = 0.9662), suggesting the process is mostly chemisorption.