Surface Characterization of WLBU2 and GP34 Chemically Immobilized on to Tcvs Modified SiO2

GP34 is a bacteria-binding tail-spike protein from bacteriophage that binds to the lipid A region of lipopolysaccharides (LPS) in bacterial membranes. N₃-Modified GP34, synthesized by Genetic Code Expansion, was covalently tethered through a copper catalyzed azide-alkyne addition to a brush layer of PBD-PEG diblocks with a terminal alkyne group. The PBD-PEG diblocks were bound to a TCVS modified surface through gamma irradiation. The biocompatibility of the GP34 was tested against WLBU2, a cationic amphiphilic peptide, which was previously being tested for endotoxin binding as well. WLBU2 was attached onto a brush layer through a conventional NHS tether. FITC Fibrinogen was then added to both brush layers to test for the repulsion of the protein, which would provide an early indication of the biocompatibility of the proteins. The absorbance of the supernatant and sample were measured using spectrophotometry at 490 nm to test for the fluorescence in solution and quantify the fibrinogen repelled. Results indicated that the brush layer with the click tethered GP34 performed better in repelling fibrinogen than its WLBU2 counterpart.