Achieving Ultra-Low Detection Limit Using Nanofiber Labels for Rapid Disease Detection

Abstract

Early diagnosis of diseases is critical in its effective management. Traditional disease detection methods require specialized equipment and trained personnel. With the introduction of rapid diagnostic test kits (RDTs), disease detection has become easier and faster. However, these RDTs have failed to compete with the specialized laboratory equipment due to their high detection limits and false alarm rates. This paper presents a novel method of using carbon nanofibers (CNFs) grown on glass microballoons (NMBs) to achieve ultra-low detection limits in RDTs. The NMBs have millions of nanosized CNFs grown on each microballoon, with each CNF having a strong bonding affinity for antibodies. The NMBs conjugated with secondary antibodies have therefore a significantly higher probability of capturing minute antigen concentrations in solution. Furthermore, the dark color formation at the capture zone makes visual disease detection possible. Human Immunoglobulin G (IgG) was selected as the model analyte to study the performance of NMBs using a sandwich immunoassay protocol. Ultra-low electrical detection limit of (4 pg/ml) and rapid response (~1 minute) was achieved using this method.

Naked-eye detection as a universal approach to lower the limit of detection of enzyme-linked immunoassays

“…In conclusion we have demonstrated that the limit of detection of colorimetric enzyme-linked immunoassays can be decreased several orders of magnitude by simply adding a small volume of chromogenic substrate during the signal generation step and detecting the resulting color changes with the naked eye. The obtained limit of detection for naked eye detection is comparable to the limit of detection of recently reported ultrasensitive detection systems that require complex instrumentation to read the signal [20]. The colorimetric signals can be recorded by taking a picture with a mobile phone.…”

Multifunctional Gold Nano-Cytosensor With Quick Capture, Electrochemical Detection, and Non-Invasive Release of Circulating Tumor Cells for Early Cancer Treatment

“…Compared with other nanoparticles, gold nanoparticles (AuNPs) provide an ideal binding site for biomolecules, which is beneficial for electron transfer to the electrode. Such characteristics have been widely used to fabricate electrochemical biosensors with improved performance ( Zhong et al, 2013 ; Gikunoo et al, 2014 ; Qian et al, 2019 ). However, few studies have investigated the effect of the size of the AuNPs on enhancing the detection performance because the size of AuNPs may affect the analysis results.…”