Human monocyte morphology is affected by local substrate charge heterogeneity

Abstract

Cells are sensitive to topological, chemical, and electrical properties 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 technology 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 microns. Human monocytes incubated on polystyrene with 3.3 microns-wide strip domains, alternately charged so as to maintain overall charge neutrality, show significant charge density and time-dependent increases (greater than twofold) in cell area and cell perimeter after challenge with a phagocytic trigger (human IgG opsonized zymosan particles). Additional utlrastructural studies on silicon dioxide substrates show charge-density-dependent qualitative morphological differences. These studies clearly demonstrate that human monocytes respond in vitro to local surface-charge heterogeneity in the absence of substrate topology and compositional variation.

Attachment, morphology, and protein expression of rat marrow stromal cells cultured on charged substrate surfaces

“…Polymeric materials with charge storage capabilities and defined surface properties were used to study neurite outgrowth and human monocyte morphology in vitro. 15,16 In the present study, we report on a novel design, using a transparent and conductive indium tin oxide (ITO) coating as an electret substrate, to investigate cellular responses to charged surfaces. By patterning the ITO into parallel electrodes using photolithography, surfaces with positive and negative charges were ar-ranged in the same culture chamber without changes in their surface chemical composition and morphology.…”