In this study, we characterize the planar surfaces of hybrid systems in every step of the bioassay process in an effort to demonstrate the significance of stability of nanofilms on the performance of bioassays; magnitude of enzymatic signal. In that regard, detection of a model protein, i.e., b-BSA bioassay was carried out on three different hybrid platforms; (1) poly(methyl methacrylate) (PMMA), was chemically modified before introducing silver thin films of thicknesses; 1 nm, 5 nm and 10 nm, (2) paper functionalized with silver nanowires (SNW), and (3) indium tin oxide (ITO) on terephthalate (PET). Bioassays for b-BSA in buffer was performed using microwave heating (MW) and at room temperature (RT, a control experiment). To assess the extent of the loss of either silver or ITO, scanning electron microscopy (SEM) and optical spectroscopy were done on the surfaces and measured the absorbance of the enzymatic product. PMMA platform exhibited significant loss of STFs (5 nm &gt; 1 nm &gt; 10 nm) from its surface while the amounts of ITO on PET at the end of the experiment were almost the same as those at the beginning of the experiment. Control experiments (i.,e RT) witnessed a significant loss of STFs relative to those completed under MW heating. PMMA + 10 nm STFs and paper + SNW showed lowest level of detection (LLOD) for b-BSA, i.e., 10-10 M while ITO displayed LLOD of 10-11 M. These results show that hybrid platforms that display physical stability can be used as assay platforms and they can improve LLOD by 10 fold.

Assessment of the physical stability of metal and metal oxide films for enhanced signal detection in colorimetric bioassays

253rd National Meeting (2017)

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