Synthesis of silica nanofibers embedded with gold nanoparticles by laser pulses and sputtering techniques

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University of New Brunswick
Many biomedical sensing applications require high electrical sensitivity as well as a method to control and implement them into biological applications. This requires a material to have both conductive and biocompatible properties. The lack of functional stability for implanted sensors has caused their restriction to short-term usage. Increasing the biocompatibility of these sensing devices generally causes a reduction in the overall conductivity due to the oxidation of the substrate. Silicon is becoming a more feasible and available option for use in these applications due to its semiconductor properties and availability. Previous work has proven the biocompatibility of porous Silicon through in-vitro testing with both SBF and NIH 3T3 culturing. A method to fabricate fibrous Silicon structures as well as control the conductivity of the latter through laser processing techniques and two coating methods are outlined in this thesis. The first involved Gold embedding through sputtering techniques, while the other utilized pre-coated Silicon <Au1000> achieved through PVD. An Nd:YAG pulsed nanosecond laser was employed to process the single crystalline Silicon wafers at a variety of line spacings, overlaps, and average powers. Controlling the scanning parameters were seen to induce the formation of nanofibrous structures. The conductivity of the samples were found to be dependent on both quantum effects and the overall Gold concentration on the surface. A biocompatibility assessment has shown traces of the elements necessary for the formation of hydroxyapatite. Overall, the method outlined in this research offers an economical and effective way to process Silicon into porous and fibrous structures while enhancing the conductivity and biocompatibility for the advancement of potential biomedical sensing and conductive tissue engineering applications.