A molecular smart surface for spatio-temporal studies of cell mobility.

Active migration in both healthy and malignant cells requires the integration of information derived from soluble signaling molecules with positional information gained from interactions with the extracellular matrix and with other cells. How a cell responds and moves involves complex signaling cascades that guide the directional functions of the cytoskeleton as well as the synthesis and release of proteases that facilitate movement through tissues. The biochemical events of the signaling cascades occur in a spatially and temporally coordinated manner then dynamically shape the cytoskeleton in specific subcellular regions.

Tailored electroactive and quantitative ligand density microarrays applied to stem cell differentiation.

The ability to precisely control the interactions between materials and mammalian cells at the molecular level is crucial to understanding the fundamental chemical nature of how the local environment influences cellular behavior as well as for developing new biomaterials for a range of biotechnological and tissue engineering applications. In this report, we develop and apply for the first time a quantitative electroactive microarray strategy that can present a variety of ligands with precise control over ligand density to study human mesenchymal stem cell (hMSC) differentiation on transparent surfaces with a new method to quantitate adipogenic differentiation. We found that both the ligand composition and ligand density influence the rate of adipogenic differentiation from hMSC's.

Spatio-temporal control of cell coculture interactions on surfaces.

Coculture control: We report a combined photochemical and electroactive self-assembled monolayer (SAM)-based substrate strategy to generate a coculture platform with spatial and temporal control of cell-cell interactions. These dynamic substrates can present a variety of ligands on the surface for biospecific interactions between the ligands and cell surface receptors. Photopatterning enables the ligands to be immobilized in patterns and even gradients.

A photo-electroactive surface strategy for immobilizing ligands in patterns and gradients for studies of cell polarization.

We report a combined photochemical and electrochemical method to pattern ligands and cells in complex geometries and gradients on inert surfaces. This work demonstrates: (1) the control of density of immobilized ligands within overlapping photopatterns, and (2) the attached cell culture patterned onto ligand defined gradients for studies of directional cell polarity. Our approach is based on the photochemical activation of benzoquinonealkanethiols.

Immobilization of ligands with precise control of density to electroactive surfaces.

We report a broadly applicable surface chemistry methodology to immobilize ligands, proteins, and cells to an electroactive substrate with precise control of ligand density. This strategy is based on the coupling of soluble aminooxy terminated ligands with an electroactive quinone terminated monolayer. The surface chemistry product oxime is also redox active but at a different potential and therefore allows for real-time monitoring of the immobilization reaction.

Syntheses of syn and anti doublebent [5]phenylene.

[structure: see text] The parent and dipropyl-substituted anti (1a,b) and syn doublebent (2a,b) [5]phenylenes have been assembled by CpCo-catalyzed double cyclization of regiospecifically constructed appropriate hexaynes. (1)H NMR, NICS, and an X-ray structural analysis of 1a reflect the aromatizing effect of double angular fusion on the central ring of the linear [3]phenylene substructure.

A novel layer-by-layer approach to immobilization of polymers and nanoclusters.

This paper reports a simple method for the multilayer immobilization of conjugated polymers, gold nanoparticles on solid supports. Poly(phenyenevinylene) functionalized with aldehyde and aminooxy groups was chemoselectively immobilized onto both glass and gold substrates via layer-by-layer deposition. The physical properties of the thin films were characterized by grazing angle IR, TM-AFM, fluorescence, and UV-visible spectroscopy.