Ultrarapid Method for Coating Electrochemical Sensors with Antifouling Conductive Nanomaterials Enables Highly Sensitive Multiplexed Detection in Whole Blood

Abstract

The commercialization of electrochemical (EC)-sensors for medical diagnostics is currently limited by their rapid fouling in biological fluids, and use of potential antifouling coatings is hindered by the complexity and cost of application methods. Here, a simple ultrafast (< 1 min) method is described for coating EC-sensors with cross-linked bovine serum albumin infused with conductive, pentaamine-functionalized, graphene particles that can be stored at room temperature for at least 20-weeks, which provides unprecedented sensitivity and selectivity for diagnostic applications. The antifouling coating is applied directly on-chip using rapid heating via simple dip-coating, which provides unprecedented high levels of electrode conductivity for up to 9-weeks in unprocessed biological samples. This method is leveraged to develop a multiplexed platform for detecting clinically relevant biomarkers including myocardial infarction and traumatic brain injury using only 15 μL of blood. Single-digit pg mL −1 sensitivity is obtained within minutes in unprocessed human plasma and whole blood, which is faster and at least 50 times more sensitive than traditional enzyme-linked immunosorbent assays, and the signal generated is stable enough to be measured after 1 week of storage. The multiplexed EC-sensor platform is validated by analyzing 22 patient samples and demonstrating excellent correlation with reported clinical values.

Electrochemical Impedance Spectroscopy (EIS) Based Label-Free Immunosensors

“…Thermal reduction has demonstrated even greater electroactivity, however the morphology of the rGO will depend on the reduction strategy [152][153] and this needs to be considered when selecting a reduction method. Graphene and its derivatives have been widely used as matrixes for the development of electrochemical biosensors [154][155][156][157][158][159] . Very recently, Khayamian et al 160 reported an impedimetric biosensor based on graphene for real-time monitoring the cytokine storm in serum which is suitable for screening COVID-19 patients.…”

A compact, low-cost, and binary sensing (BiSense) platform for noise-free and self-validated impedimetric detection of COVID-19 infected patients

“…These biosensors have been used for the early diagnosis of several diseases, such as brain injuries ( Khetani et al 2018 , 2021 ), cancer ( Akhavan et al, 2014 ; Chung et al, 2021 ; Pimalai et al, 2021 ), infectious diseases ( Idili et al, 2021 ; Wu et al, 2018 ), and other clinical and pharmaceutical applications ( Arduini et al, 2016 ; Castle et al, 2021 ; El Harrad et al, 2018 ; Monošík et al, 2012 ). For complex bodily fluids such as the blood, the matrix effect has been a critical challenge for the reliable detection of several biomarkers for which multiplex biosensors with the capability of detecting matrix effect are highly beneficial ( Gao et al, 2017 ; Liu et al, 2021 ; Salahandish et al, 2022a ; Timilsina et al, 2021 ; Zupančič et al, 2021 ). The use of multiple electrodes (Panes-Ruiz et al, 2021) in the format of electrode arrays has been also investigated as a self-validation mechanism for avoiding false-positive results, relying on the fact that the results from each electrode were comparable.…”

Biofabrication of multiplexed electrochemical immunosensors for simultaneous detection of clinical biomarkers in complex fluids

“…[5, 7] The coating method involves brief (1 minute), localized, heat-induced coating of EC sensors with a nanocomposite composed of denatured bovine serum albumin cross-linked with pentaamine functionalized graphene oxide cross-linked with glutaraldehyde (BSA/prGOx/GA). [8]…”