CHARACTERIZATION OF BIOMIMETIC SURFACES FORMED FROM CELL-MEMBRANES

A method for fabricating biomimetic surfaces from intact cell membrane s is described. A monolayer of alkanethiol on gold is covered by a sec ond layer derived from the components of erythrocyte membranes either by self-assembly or by Langmuir-Blodgett methods. The resulting asymme tric hybrid layer was characterized by ellipsometry, surface plasmon r esonance (SPR), contact angle, capacitance, voltammetry, and electron and atomic force microscopy. The erythrocyte membrane layer was measur ed to be similar to 30-40 Angstrom in thickness. Using SPR, the presen ce of erythrocyte components on the surface was demonstrated by their selective removal by enzymatic action. The uniform deposition of membr anous material on the substrate was shown by electron and atomic force microscopy. Demonstration of acetylcholinesterase (AChase) activity, a membrane-anchored enzyme, on the surface for at least 8 days, sugges ts that the outer leaflet of the erythrocyte membrane is present in it s native form. Cyclic voltammetry demonstrates that enhanced electron transport from a solution redox species accompanies formation of the e rythrocyte layer at the surface. This enhanced electron transport is b locked by 4,4'-diisothiocyanate stilbene-2,2'-disulfonic acid, a well known blocker of anion transport, suggesting that an erythrocyte anion transporter protein is incorporated into the surface layer in an acti ve conformation.