Label-Free Physiology: Photonic Crystal Enhanced Microscopy of Cardiomyocytes

Molecular and cellular mechanics play an integral role in many biologically and clinically important processes, but methods to assess the strength and health of cell attachment remain limited in both scale and throughput. To address the need for a robust method to assess the density and strength of cell attachment, we have developed Photonic Crystal Enhanced Microscopy (PCEM) – a wide-field, label-free technique designed to image cell attachment. Briefly, PCEM allows direct detection of localized changes in dielectric permittivity as cell attachment proteins are deposited on nanofabricated photonic crystal (PC) biosensors. In this work, we characterize the processes of cell adhesion, growth, movement, and differentiation as they relate to cell adhesion on a range of substrates, and in context with several cell models. Systems studied include primary cardiomyocytes, mesenchymal stem cells, and hepatic and pancreatic carcinoma cell lines. PCEM provides cell attachment information that is not available via traditional light microscopy, and as a label-free technique, it can be used to study cell and molecular mechanics over prolonged periods in the absence of perturbing or cytotoxic labels, stains, or fluorophores.