Discrimination of bladder cancer cells from normal urothelial cells with high specificity and sensitivity: combined application of AFM and modulated Raman spectroscopy

Atomic force microscopy (AFM) and modulated Raman spectroscopy (MRS) were used to discriminate between living normal human urothelial cells (SV-HUC-1) and bladder tumour cells (MGH-U1) with high specificity and sensitivity. MGH-U1 cells were 1.5-fold smaller, 1.7-fold thicker and 1.4-fold rougher than normal SV-HUC-1 cells. The adhesion energy was 2.6-fold higher in the MGH-U1 cells compared to normal SV-HUC-1 cells, which possibly indicates bladder tumour cells to be more deformable than normal cells. The elastic modulus of MGH-U1 cells was 12-fold lower than SV-HUC-1 cells, suggesting a higher elasticity of the bladder cancer cell membranes. The biochemical fingerprints of cancer cells displayed a higher DNA and lipid content probably due to an increase in the nuclear to cytoplasm ratio. Normal cells were characterised by higher protein contents. AFM studies revealed decrease in the lateral dimensions and increase in thickness of cancer cells compared to normal cells which authenticate the observations from MRS. Nanostructural, nanomechanical and biochemical profiles of bladder cells provide qualitative and quantitative markers to differentiate between normal and cancerous cells at the single cellular level. AFM and MRS allow discrimination between adhesion energy, elasticity, and Raman spectra of SV-HUC-1 and MGH-U1 cells with high specificity (83%, 98%, and 95%) and sensitivity (97%, 93%, and 98%). Such single cell-level studies could have a pivotal impact in the development of AFM-Raman combined methodologies for cancer profiling and screening with translational significance.