Light assisted molecular immobilization has been used for the first time to engineer covalent bioconjugates of superparamagnetic nanoparticles and proteins. The technology involves disulfide bridge disruption upon UV excitation of nearby aromatic residues. The close spatial proximity of aromatic residues and disulfide bridges is a conserved structural feature in proteins. The created thiol groups bind thiol reactive surfaces leading to oriented covalent protein immobilization. We have immobilized a model carrier protein, bovine serum albumin, onto Fe(3)O(4)@Au core-shell nanoparticles as well as arrayed it onto optically flat thiol reactive surfaces. This new immobilization technology allows for ultra high dense packing of different bio-molecules on a surface, allowing the creation of multi-potent functionalized active new biosensor materials, biomarkers identification and the development of nanoparticles based novel drug delivery system.

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Continuing advancements in window materials, detector modules, and electronics are leading to higher count rates, better light-element sensitivity, and improved energy-resolution stability over a wide range of count rates. In this article we will briefly review how the different parts of the EDS system interact, from X-rays leaving the sample to the production of useful data and where recent changes have taken place. We then apply the gains offered by this new technology to three samples to illustrate the benefits that can be reaped.