Nanomonitors: Electrical Immunoassays for Protein Biomarker Profiling

Abstract

The performance parameters of the nanomonitors, such as speed of detection on the order of minutes, volume of reagents of a few microliters and low cost per assay are comparable to traditional assay methods, such as ELISA. In addition, nanomonitors also provide the advantages of being a label-free technique with large linear dynamic range of detection and a significant reduction in the size of assay, thus making it an ideal candidate for a clinical diagnostic 'lab-on-a-chip' device for protein biomarker profiling and hence early disease diagnosis.

Silicon Nanosensor for Diagnosis of Cardiovascular Proteomic Markers

“…We have previously shown how this effect can help in effective signal amplification and detection. 35 Protein immunoassays are inherently limited in terms of the number of proteins that can be simultaneously detected from one assay due to the issue of nonspecific binding. This problem can only be minimized but not totally overcome.…”

“…So, theoretically, at antibody saturation, a high density of antibodies is trapped on a single sensing site. 35 In the nanowells, inoculated antibodies (size: 1-10 nm) flowed to the bottom of the well due to capillary forces and fell within the inner Helmholtz layer of the double layer, thereby causing a perturbation and producing a change in the capacitance. The charge associated with the antibody modified the double layer.…”

Novel Nanomonitor ultra-sensitive detection of troponin T

“…Measurements made with the Nanomonitor are based upon changes in impedance that occur at the electrical double layer when an antigen binds to its antibody, and have been described in detail previously [8][9][10][11][12][13]. Briefly, a nanoporous nylon membrane is integrated onto a platform composed of a gold modified branched concentric circle electrode design.…”

“…The Nanomonitor turns the impedance signal into a concentration for the target biomarker using electrochemical impedance spectroscopy. Prior work by our group showed that leveraging the phenomenon of macromolecular crowding can be utilized to design ultra-sensitive protein biosensors [8][9][10][11][12][13]. Macromolecular crowding theory postulates that the crowded environment in cells enhances protein interactions that are significantly different compared with protein interactions occurring in buffered solutions used in most laboratory-based measurement of proteins.…”

Emerging nanoproteomics approaches for disease biomarker detection: A current perspective

“…Gold interdigitated capacitor arrays [143] CRP, TNFα and IL-6 (inflammation, CVR) 25 pg-25 ng Gold integrated electrode capacitor arrays were used for detection 4.5. Nanomonitors [144] CRP and Myeloperoxidase 200-500 pg/mL Microelectrode array covered with nanoporous alumina membrane trapped the target protein [40] CA15-3 (blood) NM* AuNP-bound antibodies to CA15-3 was used for detection. Signal amplification carried out using HRP 1.6.…”