Nanomaterial-based Bioaffinity Sensors

Nanoparticle-induced changes in the conductivity across a microelectrode gap can also be exploited for highly sensitive and selective electronic detection of DNA hybridization [45, 46]. The capture of the nanoparticle-tagged DNA targets by probes confined to the gap between the two microelectrodes, and a subsequent silver enlargement, results in a conductive metal layer across the gap, and leads to a measurable conductivity signal. Target DNA concentrations down to 500 fmol can, thus, be detected with remarkable 

The ability of CNTs to facilitate the adsorptive accumulation of the guanine nucleobase can lead to a dramatic amplification of label-free electrochemical detection procedures based on the intrinsic electroactivity of DNA [52]. The coupling of a CNT nanoelectrode array with the Ru(bpy)3+ -mediated guanine oxidation has facilitated the detection of subattomoles of DNA targets [53, 54], Such CNT array was also applied for the label-free detection of DNA PCR amplicons, and offered the detection of less than 1000 target amplicons. 

---

Electrochemical Biosensors Based on Nanomaterials 321 11.3.2 Nanomaterial-based Bioaffinity Sensors... 

Potentiometric biosensors based in both ISE and ISFET for water analysis have been widely developed in the last few years, with recent research leading to nanomaterial-based devices. New nanoparticle (NP)-based signal amplification and coding strategies for bioaffinity assays are in use, along with molecular carbon-nanotube (CNT) wires for achieving efficient electrical communication with redox-enzyme and nanowire-based label-free DNA sensors. ... 

---