(14a) Investigation and Analysis of Scattered Light from the Deformation and Adhesion of Synthesis Oil-in-Water Microcapsules

Measuring the adhesion and deformation of healthy RBCs from a boundary is of great importance to the diagnosis and treatment of diseases like sickle-cell disease. However, the complexity of the bio-material and deformation ability makes it difficult to analyze. The strategy herein is to utilize synthetic microcapsules with an enclosed oil-core and a solid polymer shell that interacts with a boundary as the analog to investigate the adhesion and deformation of red blood cells. This phenomenon is not only crucial to RBC adhesion but also generally influential when soft and hard surfaces come into contact. Microcapsules are synthesized via a Pickering emulsion, which consists of cinnamon leaf oil stabilized by calcium carbonate nanoparticles in water. The shell is formed through the ion-exchange reaction and cross-linking process by sodium alginate and calcium ions. To image and measure the size of microcapsules, fluorescent tag Nile red is added in cinnamon oil to represent the size of the oil core. The size distributes from 4.3 to 5.3 μm depending on the fabrication time, and the zeta potential is around −20 mV regardless of the fabrication time. The Brownian fluctuation between the capsule and the glass substrate is measured by Scattering Morphology Resolved Total Internal Refraction Microscopy (SMR-TIRM) as it offers high energy and spatial sensitivity. The fluctuations in total scattered light intensity directly result from the fluctuations in separation distance, typically at a resolution of a few nanometers, as the evanescent wave decays exponentially with distance. The scattering light morphology of an anisotropic colloidal particle systematically changes with orientations and positions away from the substrate. We aim to analyze the mean square displacement, potential energy profile, and morphology changes in scattering light to study the adhesion and deformation of liquid containing microscale capsules interacting with solid boundaries.