Patterning of proteins and cells on functionalized surfaces prepared by polyelectrolyte multilayers and micromolding in capillaries

A method for protein and cell patterning on polyelectrolyte-coated surfaces using simple micromolding in capillaries (MIMIC) is described. MIMIC produced two distinctive regions. One contained polyethylene glycol (PEG) microstructures fabricated using photopolymerization that provided physical, chemical, and biological barriers to the nonspecific binding of proteins, bacteria, and fibroblast cells. The second region was the polyelectrolyte (PEL) coated surface that promoted protein and cell immobilization.The difference in surface functionality between the PEL region and background PEG microstructures resulted in simple patterning of biomolecules. Fluorescein isothiocyanate-tagged bovine serum albumin, E. coli expressing green fluorescence protein (GFP), and fibroblast cells were successfully bound to the exposed PEL surfaces at micron scale. Compared with the simple adsorption of protein, fluorescence intensity was dramatically improved (by about six-fold) on the PEL-modified surfaces. Although animal cell patterning is prerequisite for adhesive protein layer to survive on desired area, the PEL surface without adhesive proteins provides affordable microenvironment for cells.The simple preparation of functionalized surface but universal platform can be applied to various biomolecules such as proteins, bacteria, and cells.