Targeted-TERS detection of integrin receptors on human cancer cells.

Membrane receptors play important roles in regulating cellular activities. Targeting membrane receptors in cancer cells and understanding their interactions with specific ligands are key for cancer prognosis and therapeutics. However, there is a need to develop new technologies to provide molecular insight into ligand-receptor binding chemistry in cell membrane. Integrin receptors are important membrane receptors that regulate cellular migration, invasion and proliferation in tumors. Integrins have a well-known affinity towards small peptide ligands containing arginine-glycine-aspartate (RGD) sequence and are therefore an attractive model system to study ligand-receptor interactions. We have recently reported a method to detect integrin receptors and study their binding chemistry with cyclic-RGDfC ligand using tip-enhanced Raman scattering (TERS). We have demonstrated that two integrins with similar structures can be differentiated in intact cell membrane, due to the differences in their RGD ligand binding sites, showing the potential of this TERS methodology to study other membrane receptors and their interactions in live cells.