The role of fibrinogen spacing and patch size on platelet adhesion under flow.

Platelet adhesion to the vessel wall during vascular injury is mediated by platelet glycoproteins binding to their respective ligands on the vascular wall. In this study we investigated the roles that ligand patch spacing and size play in regulating platelet interactions with fibrinogen under hemodynamic flow conditions. To regulate the size and distance between patches of fibrinogen we developed a photolithography-based technique to fabricate patterns of proteins surrounded by a protein-repellant layer of poly(ethylene glycol).

Independently controlling protein dot size and spacing in particle lithography.

Particle lithography is a relatively simple, inexpensive technique used to pattern inorganics, metals, polymers, and biological molecules on the micro- and nanometer scales. Previously, we used particle lithography to create hexagonal patterns of protein dots in a protein resistant background of methoxy-poly(ethylene glycol)-silane (mPEG-sil). In this work, we describe a simple heating procedure to overcome a potential limitation of particle lithography: the simultaneous change in feature size and center-to-center spacing as the diameter of the spheres used in the lithographic mask is changed.

Patterning of quantum dot bioconjugates via particle lithography.

We present a simple technique to fabricate hexagonally ordered quantum dot bioconjugate (QDBC) dot arrays on glass coverslips. We used particle lithography to create periodic holes in a layer of methoxy-poly(ethylene glycol)-silane and then adsorbed QDBCs into the holes. To demonstrate the versatility of this technique, we made separate periodic arrays of quantum dots (QDs) conjugated to three different biologically important molecules: biotin, streptavidin, and anti-mouse IgG.

Fabrication of protein dot arrays via particle lithography.

The ability to pattern a surface with proteins on both the nanometer and the micrometer scale has attracted considerable interest due to its applications in the fields of biomaterials, biosensors, and cell adhesion. Here, we describe a simple particle lithography technique to fabricate substrates with hexagonally patterned dots of protein surrounded by a protein-repellent layer of poly(ethylene glycol). Using this bottom-up approach, dot arrays of three different proteins (fibrinogen, P-selectin, and human serum albumin) were fabricated.