A versatile and reliable method for patterning gold nanostructures of varying shapes is presented in this work. It begins with a close-packed array of polystyrene nanospheres, which are shaped through simple plasma etching. The vapor-deposition of nickel shadowed over the shaped maks creates the possibility of forming a wide range of gold nanostructures. This is an easy, powerful, and straightforward method that offers several degrees of freedom to precisely control the shape and size of nanostructures. We made a library of nanostructures including gold nanocrescents, double crescents, nanorings, and nanodisks with dimensions in the range of 150 to 650 nm. The fabricated nanostructures are highly packed (up to 8×108 cm-2) and uniformly cover the centimeter scale substrate. The optical properties of thesemetallic nanostructures were studied by a combination of UV-Vis-NIR and Fourier transform infrared (FTIR) spectroscopies, and the features agreed well with predicted optical responses. The materials are highly sensitive surface enhanced infrared absorption (SEIRA) substrates as was demonstrated with gold nanocrescent arrays. Gold nanocrescent arrays exhibited highly tunable plasmon resonance to cover desired molecular vibrational bands and exhibited three orders of magnitude enhancement of IR signal over the entire substrate and up to 105 SEIRA enhancement factors on hot-spot areas. These substrates are biocompatible for growth, adhesion, and proliferation of human dermal fibroblast cells. Leveraging the capability of gold nanocrescent arrays to enhance IR signals, we developed a real time SEIRA spectroscopic technique for label-free biological cell analysis. The performance of proposed method was assessed by in-situ tracking the SEIRA signal of human dermal fibroblast cells cultured on gold nanocrescent arrays.

Modified soft lithographic approach for Surface-Enhanced Infrared Spectroscopy (SEIRA) substrates and their application to live cell monitoring

253rd National Meeting (2017)

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