Biophysical and computational analyses of interaction of 2D MoS2 nanosheets with human haemoglobin coupled with NIR activated photothermal therapy

Abstract

Molybdenum disulfide (MoS₂) is one of the most extensively studied 2-dimensional transition metal dichalcogenides (2D TMDCs) owing to its high optical absorption in the near-infrared region. In this work, MoS₂ nanosheets (MoS₂ NSs) were synthesized hydrothermally and characterized using XRD, DLS, FESEM, TEM, FTIR, XPS and Raman analyses. They exhibited a higher photothermal conversion efficiency under 808 nm laser irradiation (79%) compared to that under 980 nm laser irradiation (25%). In vitro studies revealed that the treatment of cancer cells with MoS₂ nanosheets and subsequent NIR laser irradiation lead to robust photothermal cell death. Elevated levels of ROS were observed in the cells subjected to MoS₂ NS-mediated NIR photothermal therapy. Furthermore, as blood plasma is known to play a crucial role in drug delivery and targeting, we have probed the mechanistic interaction between MoS₂ NSs and human haemoglobin (Hb) using biophysical and in silico investigations. The results indicated that MoS₂ NSs successfully bind to Hb, causing secondary structure expansion and microenvironment alterations of the heme protein via formation of a ground state complex. Therefore, this work may serve as a precedent for understanding the mechanism of interaction of biological macromolecules with the efficient NIR-activated photothermal agent MoS₂ NSs.