Dose-dependent cell growth in response to concentration modulated patterns of FGF-2 printed on fibrin

Immobilized patterns of unmodified fibroblast growth factor-2 (FGF-2), with varying surface concentrations, were inkjet printed onto physiologically relevant fibrin substrates. Printed patterns were characterized using iodinated FGF-2 to determine FGF-2 surface concentration and retention of FGF-2 binding in vitro. MG-63 cells were uniformly seeded onto patterned substrates. Cells were exposed to defined spatial FGF-2 surface concentrations of 1-22 pg/mm(2). Cell numbers were observed to increase in register with the printed FGF-2 patterns from an initial random uniform cell distribution across the patterned and non-patterned regions. Based on time-lapse image analysis, the primary organizational response of the cells was determined to be proliferation and not migration. Cell counts on and off the FGF-2 patterns over time demonstrated an increase in cell density up to a FGF-2 surface concentration of 14 pg/mm(2). Higher surface concentrations did not result in increased cell density. In addition, the cells on the FGF-2 patterns survived longer than the cells off patterns. Our inkjet printing approach permits the systematic study of cellular responses to defined spatial surface concentrations of immobilized growth factors. (C) 2005 Published by Elsevier Ltd.