Hierarchical scaffolds via combined macro- and micro-phase separation.

Recent advances in biomaterial surface engineering have shown that surface biomechanical, spatial and topographical properties can elicit control over fundamental biological processes such as cell shape, proliferation, differentiation and apoptosis. Along these lines, we have very recently shown that the self-assembly of block copolymers into thin films can be used as an extremely labile method to precisely position cellular adhesion molecules, at nanometre lateral spacings, to effect control over cell attachment and morphology. Here, we extend our work in 2-dimensional block copolymer films into the production of 3-dimensional porous block copolymer scaffolds.

Nanoscale presentation of cell adhesive molecules via block copolymer self-assembly.

Precise control over the nanoscale presentation of adhesion molecules and other biological factors represents a new frontier for biomaterials science. Recently, the control of integrin spacing and cellular shape has been shown to affect fundamental biological processes, such as differentiation and apoptosis. Here, we present the self-assembly of maleimide functionalised polystyrene-block-poly (ethylene oxide) copolymers as a simple, yet highly precise method for controlling the position of cellular adhesion molecules.

Surface-bound stem cell factor and the promotion of hematopoietic cell expansion.

In vivo, stem cell factor (SCF) exists in both a bound and soluble isoform. It is believed that the bound form is more potent and fundamentally required for the maintenance of hematopoietic stem cells (HSCs). This theory is supported by the observation that steel-Dickie mice lacking the bound isoform of SCF are unable to maintain hematopoiesis and by the fact that bound SCF displayed on the surface of transgenic cells is better able to maintain c-kit activation than soluble SCF.

Self-assembling polystyrene-block-poly(ethylene oxide) copolymer surface coatings: resistance to protein and cell adhesion.

In this paper we report a method for biomaterial surface modification that utilizes the self-assembly of block copolymers of poly(styrene-block-ethylene oxide) (PS-PEO) to generate micro-phase separated surfaces with varying density PEO domains. These PS-PEO self-assembled surfaces showed a significant reduction in protein adsorption compared to control polystyrene surfaces. The adhesion of NIH-3T3 fibroblast cells was shown to be significantly affected by the surface coverage of PEO nano-domains formed by copolymer self-assembly.

Directing osteogenic and myogenic differentiation of MSCs: interplay of stiffness and adhesive ligand presentation.

The mechanical properties of the extracellular matrix (ECM) can exert significant influence in determining cell fate. Human mesenchymal stem cells (MSCs) grown on substrates with varying stiffness have been shown to express various cell lineage markers, without the use of toxic DNA demethylation agents or complex cocktails of expensive growth factors. Here we investigated the myogenic and osteogenic potential of various polyacrylamide gel substrates that were coated with covalently bound tissue-specific ECM proteins (collagen I, collagen IV, laminin, or fibronectin).