A novel method for surface modification to promote cell attachment to hydrophobic substrates

Abstract

The ability to study and regulate cell behavior at a biomaterial interface requires strict control over material surface chemistry. Perhaps the greatest challenge to researchers working in this area is preventing the fouling of a given surface due to uncontrolled protein adsorption. This work describes a method for coupling peptides to hydrophobic materials for the purpose of simultaneously preventing nonspecific protein adsorption and controlling cell adhesion. A hexapeptide containing the ubiquitous RGD cell-adhesion motif was coupled to polystyrene (PS) via a polyethylene oxide (PEO) tether in the form of a modified PEO/PPO/PEO triblock copolymer. Triblocks were adsorbed onto PS at a density of 3.3 +/- (5.14 x 10(-4)) mg/m2 (1.4 x 10(5) +/- 2.12 x 10(1) molecules/microm2), which was determined by isotope 125I labeling. The peptide, GRGDSY, was activated at the N terminus with N-Succinimidyl 3-(2-pyridyldithio) propionate and coupled to immobilized triblocks where the terminal hydroxyls had been converted to sulfhydryl groups. Surface peptide density was measured by amino acid analysis and found to be 1.4 x 10(4) +/- 0.47 x 10(4) molecules/microm2. PS modified with PEO/PPO/PEO copolymers alone was found to be inert to cell adhesion both in the presence of serum proteins and when exposed to activated RGD peptide. In contrast, PS conjugated with RGD via endgroup-activated PEO/PPO/PEO copolymers supported cell adhesion and spreading. The surface coupling scheme reported here should prove valuable for studying cell-ligand interactions under simplified and highly controlled conditions.

Surface-immobilization of adhesion peptides on substrate for ex vivo expansion of cryopreserved umbilical cord blood CD34+ cells

“…The amount of peptide conjugated to PET surface, quantified by BCA assay, was similar for all four peptide modified surfaces (2.01-2.29 nmol/cm 2 ). These conjugation degrees are substantially higher than that obtained by other conjugation schemes [42,43]. This is likely due to the improved reaction efficiencies, particularly for the final coupling step, which was performed in organic solvent instead of aqueous buffer.…”

Synthesis and Characterization of Self-Assembling Block Copolymers Containing Bioadhesive End Groups

“…Despite the numerous applications of Pluronics, relatively few attempts have been made to subject them to chemical modification. 22,23,[47][48][49] Succinimidyl carbonate has been recognized as a useful reagent for activating hydroxyl groups of small organic compounds and PEG molecules to form bioconjugates with urethane linkages. 50,51 In this work, succinimidyl carbonate was used to activate the hydroxyl groups of Pluronic F127 and Pluronic F68 in the presence of DMAP.…”

The Effect of Amino Density on the Attachment, Migration, and Differentiation of Rat Neural Stem Cells In Vitro

“…Compared with other functional groups, the positive charge and good reactivity of amino provides significant advantages in promoting NSCs attachment (Engler et al, 2006;Faucheux et al, 2004;Hung et al, 2006;Neff et al, 1998;Ren et al, 2009;Wang et al, 2006). However, the specific interactions between cells and biological materials that regulate NSCs behavior remain unknown.…”