Modulation of Stem Cell Adhesion and Morphology via Facile Control over Surface Presentation of Cell Adhesion Molecules

Abstract

ABSTRACT. To encourage cell adhesion on biomaterial surfaces in a more facile, safe, and lowcost fashion, we have demonstrated a non-covalent approach to spatially conjugate β-cyclodextrin (β-CD) modified peptide sequences onto self-assembled adamantane-terminated polystyrene-b-poly(ethylene oxide) (PS-PEO-Ada) films through inclusion complexing interactions between β-CDs and adamantane. By simply blending various ratios of unmodified PS-PEO with a newly synthesised PS-PEO-Ada, we produced PS polymer films that displayed 2 well-organized adamantine-decorated cylindrical PEO domains with varying average interdomain spacings ranging from 29 to 47 nm. The presence of the adamantane moiety at the terminal end of the PEO chain permitted rapid, and importantly, oriented attachment of β-CD functionalized peptides onto these surfaces. This one-step process not only converted these proven non-adherent PS-PEO surfaces into adherent surfaces, but also permitted precisely controlled presentation and surface distribution of the conjugated peptides. The utility of these surfaces as cell culture substrates was confirmed with human mesenchymal stem cells (hMSCs).We observed that with increasing PS-PEO-Ada content in the PEO cylindrical domains, these novel polymer films displayed improved cell attachment and spreading, with notable differences in hMSC morphology. We further confirmed that this novel PS-PEO-Ada surface provides a flexible platform for facile conjugation of mixtures of β-CDs functionalized with different peptides, specifically RGD and IKVAV peptides. The cell adhesion and spreading assays on these surfaces indicated that the morphologies of hMSCs can be easily manipulated, while no significant changes in cell attachment were observed. The 'lock-and-key' peptide conjugation technique presented in this work is applicable to any substrate that incorporates a moiety capable of forming inclusion complexes with α-, β-and γ-CDs, providing a facile and flexible method by which to construct peptide-conjugated biomaterial substrates for a multitude of applications in fields ranging from cell bioprocessing, regenerative medicine to cell-based assays.

Control of mesenchymal stem cell phenotype and differentiation depending on cell adhesion mechanism

“…However, cell adhesion is mediated by non-specific physical interactions. Several studies have been published about adhesion mechanisms that affect cell morphology and adhesion-related signal transduction (Deligianni et al, 2001;Li et al, 2013;Yeung et al, 2005). In the current study, PS-MBP-FGF2 was used as an artificial substrate to control adhesion-mediated signalling and stem cell function through a specific receptor-ligand interaction.…”

“…For example, although hMSCs differentiate into osteoblasts under culture conditions in which their spread out shape is maintained, hMSCs that maintain a rounded morphology differentiate into adipocytes (McBeath et al, 2004). We reported that hASCs differentiate more readily into adipocytes than osteoblasts on surfaces with immobilised FGF2, suggesting that hASC differentiation is strongly correlated with the cell adhesion mechanism and that surfaces displaying immobilised FGF2 can serve as a unique artificial matrix for regulating integrin-mediated signalling and stem cell differentiation through FGF2-HSPG interactions (Kang et al, 2012).…”

Supramolecular Guest–Host Interactions for the Preparation of Biomedical Materials

“…In concurrent work, the Cooper-White group used supramolecular interactions to display RGD in nanopatterned topographies produced by the segregation of Ad terminated polystyrene-co-PEO block copolymers (PS-PEO-Ad). 112 Such topographies are known to influence cell behaviors, including adhesion, spreading, and differentiation. [113][114][115] The ratio of PS-PEO/PS-PEO-Ad used to control the concentration of βCD-RGD bound within the nanodomains influenced cell adhesion and area.…”

Can single molecule localization microscopy be used to map closely spaced RGD nanodomains?

“…For example, a polystyrene-poly(ethylene oxide) (PS-PEO) copolymer system [39] was used to engineer a controlled cellular microenvironment for mesenchymal stem cells that contained nanodomains decorated with cell adhesion peptides [40]. We have produced surfaces where vertical cylinders of PEO in thin films of PS-PEO:PS mixtures on glass coverslips formed nanodomains [41] that were easily detectable as ~ 3 nm indentations with AFM (Fig 1A–1C, Figure A (B-C) in S1 File).…”