Programming the detection limits of biosensors through controlled nanostructuring

Abstract

Advances in materials chemistry offer a range of nanostructured shapes and textures for building new biosensors. Previous reports have implied that controlling the properties of sensor substrates can improve detection sensitivities, but the evidence remains indirect. Here we show that by nanostructuring the sensing electrodes, it is possible to create nucleic acid sensors that have a broad range of sensitivities and that are capable of rapid analysis. Only highly branched electrodes with fine structuring attained attomolar sensitivity. Nucleic acid probes immobilized on finely nanostructured electrodes appear more accessible and therefore complex more rapidly with target molecules in solution. By forming arrays of microelectrodes with different degrees of nanostructuring, we expanded the dynamic range of a sensor system from two to six orders of magnitude. The demonstration of an intimate link between nanoscale sensor structure and biodetection sensitivity will aid the development of high performance diagnostic tools for biology and medicine.

Effect of Nanoporous Gold Thin Film Morphology on Electrochemical DNA Sensing

“…A similar tuning phenomenon was observed for dendritic electrode structures obtained by electrodeposition of palladium thin films. For this convex electrode geometry, which can be conceptualized as an inverse geometry of the largely concave np-Au geometry, the enhanced sensor performance was attributed to larger deflection angles between grafted probe molecules enabled by small radius of curvature of the electrode nanostructures 16,51,52 . Finally, it should be noted that the sensor discussed in this study was not optimized for lower detection limits and it can be significantly improved by reducing electrochemical cell volume (e.g., via microfluidics) and electrode size to optimize target-to-electrode transport and reaction rates 53,54 .…”

Integrated nanostructures for direct detection of DNA at attomolar concentrations

“…Motivated by previous reports showing that nanostructuring can provide major improvements in the detection limits of biosensors, [23][24][25] we sought to incorporate such nanostructures on our microelectrodes. We found that elec- trodeposition of Au, Pd, and Pt resulted in nanostructured microelectrodes when a suitable plating potential and supporting electrolyte was chosen.…”

Carbon nanomaterials field-effect-transistor-based biosensors

“…2,3 In particular, researchers around the world have been tailor-making a multitude of nanomaterials-based electrical biosensors and developing new strategies to apply them in ultrasensitive biosensing. Examples of such nanomaterials include carbon nanotubes, [4][5][6][7][8][9][10][11][12][13] nanowires, 11,[14][15][16][17][18][19][20][21] nanoparticles, 6,[22][23][24][25] nanopores, 26,27 nanoclusters 28 and graphene. 5,[29][30][31][32] Compared with conventional optical, biochemical and biophysical methods, nanomaterial-based electronic biosensing offers significant advantages, such as high sensitivity and new sensing mechanisms, high spatial resolution for localized detection, facile integration with standard wafer-scale semiconductor processing and label-free, real-time detection in a nondestructive manner.…”