Application of X-ray microanalysis to the study of cell physiology in cells attached to biomaterials.

X-ray microanalysis is commonly applied in biomaterials research to study changes in biomaterial composition, calcifications, or to identify particulates in tissue that has been in contact with biomaterials. Studies where the effect of biomaterials on the naturally occurring elements in the cells are studied are rare. Exposure to or contact with biomaterials may give rise to several cellular reactions with characteristic changes in elemental patterns. Experimental systems in which cultured cells are exposed to biomaterials, and the resulting changes in elemental content measured by X-ray microanalysis are presented. Proliferation results in an increase in Mg, P and K. Injury and necrosis result in increased Na, Cl and Ca, and decreased K and Mg. The Na/K ratio is a sensitive indicator of cell damage. Apoptosis results in increased Na/K and an increase P/S ratios. Mechanical effects of biomaterials may cause changes in cell-shape or cell volume that may result in volume-regulating ion fluxes, e.g., of chloride, accompanied by efflux of potassium. The multi-element detection capability of X-ray microanalysis makes it particularly suitable to detect these characteristic patterns of changes. The technique can also be used to define sub populations of cells that differ with respect to their reactions to external stimuli.