title: Enantiopure chiral poly(glycerol methacrylate) self-assembled monolayers knock down protein adsorption and cell adhesion.
abstract: Chirality plays a fundamental role not only in biological systems, but also in synthetic materials intended for bio-applications. Self-assembled monolayers (SAMs) are prepared on gold surfaces through a "grafting to" method from racemic or enantiopure chiral poly(glycerol methacrylate)s (PGMA(rac), PGMA(R), and PGMA(S)), having a thiol endgroup. Such SAMs constitute a chemically and structurally well-defined model substrate for studying protein adsorption and cell adhesion as a function of the polymer chirality. Surface plasmon resonance measurements reveal that PGMA SAMs greatly reduce the adsorption of bovine serum albumin (BSA) compared to bare gold surfaces. Interestingly, enantiopure SAMs based on PGMA(R) or PGMA(S) show a significantly larger reduction in BSA adsorption than PGMA(rac)-covered surfaces. Studies with the monocytic cell line THP-1 show a similar relationship between enantiopurity of PGMA SAMs and the extent of cell adhesion. Ellipsometry and Raman spectroscopy measurements indicate that SAMs formed by PGMA(rac) have a higher grafting density compared to SAMs of PGMA(R) and PGMA(S). This seems to be due to the ability of PGMA(rac) to form more intermolecular hydrogen bonds among polymer chains compared to the enantiopure PGMAs. Circular dichroism spectroscopy provide evidence that enantiopure polymers adopt a chiral ordered conformation, most likely helical, in aqueous solutions. It is concluded that a higher water content of SAMs formed by enantiopure PGMA(S) and PGMA(R) SAMs arises from the macromolecular chiral conformation adopted by their enantiopure PGMA chains, and it is the decisive reason for the reduced BSA adsorption and cell adhesion as compared to PGMA(rac) SAMs.
authors.affiliation: Department of Chemistry, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 4, D-06099 Halle (Saale), Germany.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Li
authors.forename: Alexander
authors.initials: A
authors.lastname: Köwitsch
authors.forename: Guoying
authors.initials: G
authors.lastname: Zhou
authors.forename: Thomas
authors.initials: T
authors.lastname: Groth
authors.forename: Bodo
authors.initials: B
authors.lastname: Fuhrmann
authors.forename: Marcus
authors.initials: M
authors.lastname: Niepel
authors.forename: Elkin
authors.initials: E
authors.lastname: Amado
authors.forename: Jörg
authors.initials: J
authors.lastname: Kressler
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002942:Circular Dichroism; D006801:Humans; D006860:Hydrogen Bonding; D011109:Polymethacrylic Acids / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000378:metabolism; D013059:Spectrum Analysis, Raman; D013237:Stereoisomerism; D020349:Surface Plasmon Resonance
chemical_list: D011109:Polymethacrylic Acids; C042535:polyglycidyl methacrylate; D012710:Serum Albumin, Bovine
keywords: cell adhesion; chiral polymers; poly(glycerol methacrylate); protein adsorption; self-assembled monolayers