The effects of exposure to transition metal dichalcogenides on cell viability and substrate adhesion

Abstract

Cells experience and transmit mechanical forces in multicellular systems, such as tumors and tissues, because of cellular activity. Studying these forces allows understanding of how cells’ mechanical states relate to collective cell behavior. Several techniques, such as three-dimensional traction force microscopy (3D TFM), have enabled quantification of pressure fields surrounding tumors. TFM is a widely used tool that utilizes probes to measure deformation exerted by cells onto the extracellular matrix (ECM). The implementation of internal probes within multicellular systems has enabled measurement of their interior forces. However, determining internal forces of multicellular structures remains a challenge as spatial resolution is limited by probe size and distribution. Transition metal dichalcogenides (TMDs) are a class of two-dimensional (2D) nanomaterials whose electronic bandgap is sensitive to mechanical strain. Strain-induced changes in the bandgap produce measurable shifts in their optical spectra (e.g., photoluminescence or Raman signals), which allow detection of local mechanical deformation. This makes TMDs promising candidates as nanoscale strain sensors. Although their cytotoxicity effects and drug delivery capabilities have been widely studied in the biomedical field, their application as intracellular strain sensors remains unexplored. If successfully implemented, TMD probes can enable highly localized measurements of pressure fields within a tumor. In this research, we aimed to characterize the cell culture conditions for employing TMDs as intracellular mechanical probes by identifying parameters that allow optical characterization while maintaining cell viability. Cell substrates, TMD dispersion protocols, and sample preparation methods were evaluated to preserve cell culture quality while ensuring clear optical imaging. Additionally, cell viability was observed under different concentrations of TMDs. This work provided foundational insight towards integrating TMD nanomaterials as intracellular strain reporters in tissue-scale biomechanics.