Enhancing the Sensitivity of the Virus BioResistor by Overoxidation: Detecting IgG Antibodies

Abstract

The Virus BioResistor (VBR) is a biosensor capable of rapid and sensitive detection of small protein disease markers using a simple dip-and-read modality. For example, the bladder cancer-associated protein DJ-1 (22 kDa) can be detected in human urine within 1.0 min with a limit of detection (LOD) of 10 pM. The VBR uses engineered virus particles as receptors to recognize and selectively bind the protein of interest. These virus particles are entrained in a conductive poly(3,4-ethylenedioxythiophene) or PEDOT channel. The electrical impedance of the channel increases when the target protein is bound by the virus particles. But VBRs exhibit a sensitivity that is inversely related to the molecular weight of the protein target. Thus, large proteins, such as IgG antibodies (150 kDa), can be undetectable even at high concentrations. We demonstrate that the electrochemical overoxidation of the VBR's PEDOT channel increases its electrical impedance, conferring enhanced sensitivity for both small and large proteins. Overoxidation makes possible the detection of two antibodies, undetectable at a normal VBR, with a limit of detection of 40 ng/mL (250 pM), and a dynamic range for quantitation extending to 600 ng/mL.

Emerging Methods in Biosensing of Immunoglobin G—A Review

“…Despite the fact that this type of biosensing is noninvasive and research is being conducted on nonenzymatic forms of detection, such as cholesterol detection, the current market uses an enzymatic form of detection, which has some drawbacks in the form of fluctuations in conductivity due to enzymatic reactions and the conductivity of the electrolyte solution [ 76 ]. Okafor et al, proposed a conductometric biosensor based on polyaniline (PANI) for the detection of Johne’s disease-specified IgG antibodies [ 77 ]. This sensor was further compared with the detection of IgG with ELISA, and this study confirmed the moderate agreement between both techniques [ 78 ].…”

Novel Electrochemical Biosensing Strategy for Antibody IgG detections

“…To address this limitation, the PEDOT channel of the VBR is subjected to a simple electrochemical process called potentiostatic overoxidation, which reduces the conductivity of the polymeric channel. 73 The resulting biosensors, known as O 2 VBRs, exhibit enhanced sensitivity to both small and large proteins. For instance, two undetectable antibodies at normal VBRs can be detected using O 2 VBRs with a limit of detection of 40 ng/mL and a dynamic range for quantitation extending to 600 ng/mL.…”

Living virus‐based nanohybrids for biomedical applications

“…Viral bioresistance (VBR), as a biosensor, employs virion as a receptor to rapidly and sensitively detect small protein disease indicators via a simple dip-and-read method (Bhasin et al, 2021). Typically, this technology utilizes biomarker-binding moiety-engineered VBR viruses that are incorporated into films of electronically conductive polymers, such as poly-3,4-ethylenedioxythiophene (PEDOT).…”

“…Once the virions recognized and captured the electrical insulating DJ-1, the conductivity of the resistance channel would decrease, resulting in a LOD of 10 pM (Figure 3b). Unfortunately, the VBR seems to be insensitive to larger molecular proteins (Bhasin et al, 2021). To address this issue, Jia et al presented a new direct detection method for large cancer markers or even cancer cells based on phage-light addressable potentiometric sensing (LAPS; Jia et al, 2007).…”