(218j) Modelling the Effects of Particle Surface Loading on Cell Deformation

Interactions of nano- and micron-sized particles with cell membranes underpins many modern biomedical processes, particularly in drug delivery and cell therapies. Current models generally depict the cell membrane as a fluid 2D shell with bending and dilatational moduli, at times with the addition of an elastic contribution representing the cytoskeletal network. When a particle adheres to the cell surface through specific or non-specific interactions, one seeks to determine the degree of wrapping as a function of various biophysical parameters. However, it is usually unclear how the cell deformation is altered by particle adhesion, which may affect, for example, membrane stability, particle uptake, or even the flow of erythrocytes in blood vessels. Furthermore, current models generally consider only individual particle-membrane interactions, a situation which is rarely relevant in biomedicine for engineered cells. To study these questions, we have developed a semi-analytical model of multiple particles attaching to a cell membrane at a particular surface fraction (or surface loading). This model incorporates both bending and dilatation of the membrane, and can predict changes in the degree of wrapping, and energy landscape for a wide range of microparticle and nanoparticle sizes and adhesion strengths. Beyond mechanistic insights into particle loading on cell surfaces, we hope to validate our model against experiments and present optimal cell therapy design parameters to advance biomedicine.