Real-time monitoring of macromolecular biosensing probe self-assembly and on-chip ELISA using impedimetric microsensors

Abstract

This paper presents a comprehensive study of the self-assembly dynamics and the biosensing efficacy of Tobacco mosaic virus-like particle (TMV VLP) sensing probes using an impedimetric microsensor platform. TMV VLPs are high surface area macromolecules with nanorod structures constructed from helical arrangements of thousands of identical coat proteins. Genetically modified TMV VLPs express both surface attachment-promoting cysteine residues and FLAG-tag antibody binding peptides on their coat protein outer surfaces, making them selective biosensing probes with self-assembly capability on sensors. The VLP self-assembly dynamics were studied by the continuous monitoring of impedance changes at 100Hz using interdigitated impedimetric microsensors. Electrical impedance spectroscopy revealed VLP saturation on impedance sensor surface with the coverage of 68% in self-assembly process. The VLP-functionalized impedance sensors responded to 12ng/ml to 1.2μg/ml of target anti-FLAG IgG antibodies in the subsequent enzyme-linked immunosorbent assays (ELISA), and yielded 18-35% total impedance increases, respectively. The detection limit of the target antibody is 9.1ng/ml using the VLP-based impedimetric microsensor. These results highlight the significant potential of genetically modified VLPs as selective nanostructured probes for autonomous sensor functionalization and enhanced biosensing.

A microfluidic based biosensor for rapid detection of Salmonella in food products

“…In the equivalent circuit, C dl and R Sol are connected in parallel with the direct capacitive coupling between the electrodes (C cell ) which depends on the solution dielectric property and the geometry of the electrodes [45]. The parasitic resistors (R pa ) represents resistance from electrical connections and wires of the circuit which is small and thus can be neglected [45, 46]. R Sol and the two capacitors C dl impedance together will determine the overall impedance, which is expressed as: …”

Microfluidic based impedance biosensor for pathogens detection in food products

“…This thin layer of particles generates capacitance C dl , while the dielectric capacitance C de represents the overall capacitance of the dielectric medium. Both C dL and R Sol are connected in parallel with the direct capacitive coupling between the electrodes (C Cell ), which depends on the solution dielectric constant and the geometry of the electrodes . The parasitic resistors (R Par ) are generated from the connections and wires of the measuring circuit which is small and can be neglected.…”

Morphology engineering of ZnO nanostructures for high performance supercapacitors: enhanced electrochemistry of ZnO nanocones compared to ZnO nanowires

“…TMV contains 2130 copies of densely arranged identical coat proteins (CPs) with controllable biological affinity to a variety of materials. Recent development in genetic engineering on these TMV protein structures and affinities has enabled the integration of TMV and its virus-like particle mutant as functional materials in microdevices [13][14][15][16][17]. In order to facilitate surface attachment of the TMV molecules on inorganic device surface, TMVs have been genetically modified to let the TMV CPs express cysteine residues for enhanced gold binding affinity.…”