Assembling Vertical Nanogap Arrays with Nanoentities for Highly Sensitive Electrical Biosensing

Nanogap biosensors have emerged as promising platforms for detecting and measuring biochemical substances at low concentrations. Although the nanogap biosensors provide high sensitivity, low limit of detection (LOD), and enhanced signal strength, it requires arduous fabrication processes and costly equipment to obtain micro/nanoelectrodes with extremely narrow gaps in a controlled manner. In this work, we report the novel design and fabrication processes of vertical nanogap structures that can electrically detect and quantify low-concentration biochemical substances. Approximately 40 nm gaps are facilely created by magnetically assembling antibody-coated nanowires onto a nano -disk patterned between a pair of microelectrodes. Analyte molecules tagged with conductive nanoparticles are captured and bound to nanowires and bridge over the nanogaps, which consequently causes an abrupt change in the electrical conductivity between the microelectrodes. Using biotin and streptavidin as model antibodies and analytes, we demonstrated that our nanogap biosensors can effectively measure the protein analytes with the LOD of similar to 18 pM. The outcome of this research could inspire the design and fabrication of nanogap devices and nanobiosensors, and it would have a broad impact on the development of microfluidics, biochips, and lab-on-a-chip architectures.

Automated summary

Nanogap biosensors are promising platforms for detecting biochemical substances at low concentrations, but their fabrication processes and equipment can be arduous and costly. This research presents a novel design and fabrication process of vertical nanogap structures that can detect and quantify low-concentration biochemical substances. The nanogaps are created by magnetically assembling antibody-coated nanowires onto a nano-disk patterned between microelectrodes. The outcome of this research could inspire the design and fabrication of nanogap devices and nanobiosensors, with broad impacts on microfluidics, biochips, and lab-on-a-chip architectures.