The formation of a protein corona and the interaction with α-amylase by chitin nanowhiskers in simulated saliva fluid. (May 2020) - Wang, Yihui
Abstract: When nanomaterials (NMs) enter a physiological environment, a protein corona (PC) forms on them immediately and affects their behavior. In the current study, we investigated the interaction between chitin nanowhiskers (CNWs) and α-amylase in a simulated saliva fluid (SSF). The results showed that α-amylase bound to the CNWs in SSF, forming a PC. The PC changed the surface charge of these CNWs from 7.31 ± 0.22 to −5.53 ± 0.35 mV. Quartz crystal microbalance results suggested that, as the α-amylase concentration increased, the mass of the soft corona nearly doubled. Although the mass of the hard corona also increased, from 610 to 665 ng/cm 2, the increase was not significant. Raman spectra indicated that the CNWs induced secondary structural alterations in the α-amylase, decreasing α-helix content by 23.2% and increasing β-sheet content by 16.4%. Isothermal titration calorimetry suggested that the α-amylase adsorption onto the CNWs was primarily driven by a hydrophobic interaction. The results of an activity assay showed that α-amylase activity increased by approximately 22% at a CNW concentration of 2.5 mg/mL. Graphical abstract: Image 1 Highlights: Chitin nanowhiskers formed a protein corona in simulated saliva fluid. The protein corona changed the charge of chitin nanowhiskers from 7 mV to – 6 mV. The binding process was mainly driven by a hydrophobic interaction. The changes in α-amylase structure caused its activity increase.