Quantitative Evaluation of Cancer Cell Adhesion to Self-Assembled Monolayer-Patterned Substrates by Reflection Interference Contrast Microscopy

Adhesion of cancer cells with different metastatic potential and anticancer drug resistance has been quantitatively evaluated by using self-assembled monolayer (SAM)-patterned substrates and reflection interference contrast microscopy (RICM). Cell-adhesive SAM spots with optimized diameter could prevent cell–cell adhesion and thus allowed the systematic evaluation of statistically reliable numbers of contact area between single cancer cells and substrates by RICM. The statistical image analysis revealed that highly metastatic mouse melanoma cells showed larger contact area than lowly metastatic cells. We also found that both cancer cell types exhibited distinct transition from the “strong” to “weak” adhesion states with increase in the concentration of (−)-epigallocatechin gallate (EGCG), which is known to exhibit cancer preventive activity. Mathematical analysis of the adhesion transition revealed that adhesion of the highly metastatic mouse melanoma cells showed more EGCG tolerance than that of lowly metastatic cells. Moreover, time-lapse RICM observation revealed that EGCG weakened cancer cell adhesion in a stepwise manner, probably via focal adhesion complex. These results clearly indicate that contact area can be used as a quantitative measure for the determination of cancer phenotypes and their drug resistance, which will provide physical insights into the mechanism of cancer metastasis and cancer prevention

Spin-to-orbital angular momentum conversion in focusing, scattering, and imaging systems

We present a general theory of spin-to-orbital angular momentum (AM) conversion of light in focusing, scattering, and imaging optical systems. Our theory employs universal geometric transformations of nonparaxial optical fields in such systems and allows for direct calculation and comparison of the AM conversion efficiency in different physical settings. Observations of the AM conversions using local intensity distributions and far-field polarimetric measurements are discussed.Comment: 17 pages, 8 figure