Exploring the Interaction of Fullerenol with Key Digestive Proteases Using Raman-Based Frequency-Shift Sensing and Molecular Simulation Analysis

Fullerenol has been demonstrated to be a potential anticancer nanodrug thanks to its excellent antioxidant properties. In this work, surface-enhanced Raman scattering (SERS)-based frequency shift method is employed to explore the interaction between fullerenol and the key digestive proteases (pepsin and trypsin) in the gastrointestinal tract. A dynamic adsorption process of fullerenol on pepsin/trypsin has been monitored by our detection platform. The binding sites of fullerenol to trypsin and pepsin are evidenced by introducing their inhibitors to the detection system, and the binding configurations/modes of fullerenol to pepsin and trypsin are precisely determined through computational simulations. The permeability of fullerenol through intestinal epithelial cells monolayer is also investigated and the results show that it can reach 6% in 6 h and 13% in 48 h, indicating its high oral bioavailability in human body. This work demonstrates the activity of fullerenol in the gastrointestinal tract and provides potential guidance for appropriate oral medicine design with the aid of a molecular docking method.