Reflection Interference Contrast Microscopy: A New Tool to Study Particle-Surface Interactions and Interfacial Phenomena

Reflection interference contrast microscopy (RICM) is a microinterferometric technique that provides valuable information about the topography of an object close to a surface. RICM capabilities, such as contact area and particle shape determination, have been traditionally used in adhesion studies of cells and lipid vesicles, although a significant drawback has been the complexity of the image analysis required for accurate results. Here we introduce a novel experimental method based on RICM that overcomes this limitation and opens new possibilities to study dynamic interactions between surfaces and micron-size objects and other interfacial phenomena. The precise topographical information in RICM images is retrieved with nanometric resolution using a simplified model of RICM image formation. Therefore, our approach provides a rapid and accurate reconstruction of the object shape in the vicinity of contact with a surface. Different scenarios for the application of the method are considered; for instance, polymer vesicles and polystyrene particles close to a substrate and micron-size droplets deposited on glass.