| AVS 57th International Symposium & Exhibition | |
| Biomaterial Interfaces | Wednesday Sessions |
| Session BI-WeA |
| Session: | Proteins & Peptides on Surfaces |
| Presenter: | K.P. Fears, Naval Research Laboratory |
| Authors: | K.P. Fears, Naval Research Laboratory J.L. Kulp, Naval Research Laboratory T.D. Clark, Naval Research Laboratory D.Y. Petrovykh, Naval Research Laboratory |
| Correspondent: | Click to Email |
The adsorption behavior of model GG-X-GG and Xn oligopeptides on Au and native Si oxide substrates was investigated to elucidate the contributions of different amino acids (AAs) to peptide-surface interactions. The manner in which peptides and proteins interact with surfaces is of critical importance in many biological and technological systems. The mechanisms underlying surface adsorption of proteins, however, are poorly understood, largely due to the inherent complexity of natural proteins. Accordingly, in this work simple model peptides were chosen to systematically examine the interactions between natural AAs and inorganic surfaces. Surface interactions of a series of AAs were probed by incubating inorganic substrates in aqueous solutions of model GG-X-GG pentapeptides, in which an AA of interest was flanked with Gly. The effects of cooperative adsorption were also examined using model Xn oligopeptides (n = 5, 10). The amount of peptides that irreversibly adsorbed on each substrate was quantified by X-ray photoelectron spectroscopy (XPS), the resulting systematic data revealed several trends in surface adsorption of oligopeptides as a function of their composition and length. On the negatively-charged, hydrophilic native SiOx layer of a Si wafer, only peptides containing positively-charged residues (Lys and Arg) and polar residues (Ser and Thr) adsorbed at significant levels. Peptides adsorbed more readily on Au-coated Si wafers, on which the maximum surface coverage was ca. 3 times greater than that on the native SiOx. For a particular AA (X), adsorption tended to increase, sometimes dramatically, with increasing units of X (GG-X-GG < X5 < X10). In pairs of AAs having side chains that only vary by alkyl chain length (L and V, Q and N, R and K, E and D), the AA with the longer alkyl chain adsorbed more readily, although this trend diminished with the increasing number of X residues.