Abstract

Microfluidic and microphotonic devices have become increasingly effective for diagnostic, clinical, and biochemical applications. Such technologies usually contain polymer materials, as their properties make them highly desirable for sensing possibilities. A useful addition to these materials are gold nanoparticles (GNP), which hold unique localized surface plasmon resonance (LSPR) properties that are affected by their structure, shape, distribution, and their degree of penetration into the surrounding medium. These characteristics, in turn, depend on the thermal history of the sample, that is, the extent and duration of heating of the polymer-GNP systems.

In this undertaking, thermally tunable gold-polymer nanocomposite platforms, which have customizable properties, are fabricated for emerging opto-fluidic applications. This is achieved using a thermal convection method using six polymer films: poly (vinyl alcohol) (PVA), SU-82, poly (styrene) (PS), poly (dimethyl siloxane) (PDMS), cyclic olefin copolymer (COC), poly (methyl methacrylate) (PMMA). In order to increase the plasmonic sensitivity of the platforms, the nanocomposites are, subsequently, subjected to heat treatment with incremental heating in the range of 80-2000C. It is found that, among the polymers studied in this work, PVA and SU-82 show the largest shift of the Au LSPR band upon incremental heating as well as the highest plasmonic sensitivity. To test the biocompatibility of these different polymers, tagged antibodies are immobilized on the functionalized polymer films, and then the corresponding antigens are allowed to interact with the antibodies. The results of this work will be helpful in selecting a suitable material for both microfluidic and microphotonic experiments.