Graphene-based working electrodes are extensively used within biomolecular electrochemical sensors due to their wide potential window, rapid electron transfer kinetics and electrocatalytic abilities. However, immobilization of bio-receptors on graphene, for the purpose of selective binding with target analytes, can degrade its electrical properties. Furthermore, for the purpose of detecting trace levels of analytes, there is a need to couple microfluidic enrichment of the biomarker with its <i>in situ</i> electrochemical detection, while minimizing background capacitance from non-electroactive regions. We address these challenges by patterning graphene-gold nanocomposites (Gr-AuNs) anchored with bioreceptors on a plastic chip and aligning this bio-active region within a nanoslit channel that is embossed on cyclic olefin copolymer (COC), so that dielectrophoretic enriched analytes can be locally enriched and selectively bound to enhance detection sensitivity and selectivity. Microchannels connected to several nanoslits enable sample filling and exchange by electrokinetic means. The COC substrate with channels was aligned via imprint lithography (as indicated schematically in Fig. 1a) and bonded to the COC cover slip with patterned Gr-AuNs, as per Fig. 1c. The bonding was done at room temperature with pressure applied only to the COC substrate with the fluidic channels, so that the bioreceptors immobilized on the COC coverslip were not damaged [1, 2]. Dielectrophoresis of neuropeptide Y (NPY) was performed at 3 MHz to enrich the biomarker within the nanoslit channel in vicinity of the immobilized aptamer receptors (Fig. 1c) and standard differential pulse voltammetry (DPV) techniques were used to quantify NPY (Fig. 1b). The presentation will also present the application of the immonoassays within this sensing platform [3].

Patterned graphene gold nanocomposites for electrochemical detection of microfluidic enriched biomarkers

254th National Meeting (2017)

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