Jason P Hayes

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In this paper, we describe the development and characterization of a biochip platform for cell transfection assays. Silicon wafers were surface modified by plasma polymerization of allylamine plasma polymer (ALAPP) and grafting of a protein-resistant layer of poly(ethylene oxide) (PEO) on the plasma polymer surface. Excimer laser ablation was then used to(More)
In this paper, the realization of microfluidic packages by bonding several stacked layers of microstructured polymer films in a reel-to-reel manufacturing system is shown to be a promising approach. The smart division between disposable and reusable system parts as well as the careful selection of materials, based on microstructuring, bonding,(More)
The spatial control over biomolecule- and cell-surface interactions is of great interest to a broad range of biomedical applications, including sensors, implantable devices and cell microarrays. Microarrays in particular require precise spatial control and the formation of patterns with microscale features. Here, we have developed an approach specifically(More)
We review the current work on x-ray phase vortices. We explain the role of an x-ray vortex in phase recovery and speculate on its possible applications in other fields of x-ray optical research. We present our theoretical understanding of the structure of phase vortices and test these predictions against experiment. We present experimental observations of(More)
We have previously demonstrated that it is possible to fabricate densely-packed high aspect ratio structures in SU-8 by means of a top-plate support member which stiffens the overall structure and prevents pattern collapse. In this work we have computed the tensile stresses induced in the top-plate structures due to the capillary forces that arise between(More)
This paper presents the results on single-shot laser micromachining of filtered arc deposited TiN films and compares the machining characteristics of the films deposited under partially and fully filtered conditions. Machining performance was evaluated in terms of patterning quality and the ability to perform selective removal of top TiN film with minimal(More)
Phase singularities are a ubiquitous feature of waves of all forms and represent a fundamental aspect of wave topology. An optical vortex phase singularity occurs when there is a spiral phase ramp about a point phase singularity. We report an experimental observation of an optical vortex in a field consisting of 9-keV x-ray photons. The vortex is created(More)
The manipulation of biomolecules at solid/liquid interfaces is important for the enhanced performance of a number of biomedical devices, including biochips. This study focuses on the spatial control of surface interactions of DNA as well as the electro-stimulated adsorption and desorption of DNA by appropriate surface modification of highly doped p-type(More)
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