HUMAN MONOCYTE MORPHOLOGY IS AFFECTED BY LOCAL SUBSTRATE CHARGE HETEROGENEITY

Cells are sensitive to topological, chemical, and electrical propertie s of substrates on which they are grown. However, most studies of cell -surface interactions have neglected electrical effects or confounded them with other substrate properties. The use of nanofabrication techn ology has made it possible to fabricate optically transparent surfaces with controlled chemistry and topology, and with active, controllable surface charge density in domains as small as 1-4 mu m. Human monocyt es incubated on polystyrene with 3.3 mu m-wide strip domains, alternat ely charged so as to maintain overall charge neutrality, show signific ant charge density and time-dependent increases (greater than twofold) in cell area and cell perimeter after challenge with a phagocytic tri gger (human IgG opsonized zymosan particles). Additional ultra-structu ral studies on silicon dioxide substrates show charge-density-dependen t qualitative morphological differences. These studies clearly demonst rate that human monocytes respond in vitro to local surface-charge het erogeneity in the absence of substrate topology and compositional vari ation. (C) 1996 John Wiley & Sons, Inc.