Ultra-Fast Electrochemical Sensor for Point-of-Care COVID-19 Diagnosis Using Non-Invasive Saliva Sampling

Abstract

Point-of-care diagnostic devices that are rapid and reliable remain as an unmet need highlighted by the coronavirus disease (COVID-19) pandemic crisis. The second/third wave of virus spread in various parts of the world combined with new evidence of re-infections and inadequate healthcare facilities demand increased testing rate to diagnose COVID-19 at its core. Although traditional molecular diagnostic tests have served this purpose, there have been shortage of reagents and other supplies at pandemic frontlines. This calls for novel alternate diagnostic processes with potential for obtaining emergency use authorization and that can be deployed in the field at the earliest opportunity. Here, we show an ultra-fast SARS-CoV-2 detection sensor for detecting coronavirus proteins in saliva within 100 milliseconds. Electrochemical oxidation of nickel hydroxide has been controlled using cyclic voltammetry and chronoamperometry techniques for successful detection of SARS-CoV-2. Test results have proven the capability of sensors to quantitatively detect the concentration of virus in blinded analyses. The detection occurs by a process similar to that of SARS-CoV-2 binding onto host cells. The sensor also shows prospects in distinguishing SARS-CoV-2 from other viruses such as HIV. More importantly, the sensor matches the detection limit of the gold standard test for diagnosing early infection. The use of saliva as a non-invasive sampling technique combined with the portability of the instrument has broadened the potential of this sensor.

Controlled, partially exfoliated, self-supported functionalized flexible graphitic carbon foil for ultrasensitive detection of SARS-CoV-2 spike protein

“…It is interesting to note that the baseline of DPV responses, due to the [Fe(CN) 6 ] 3−/4− redox couple, in the latter samples without SARS-CoV-2 SP overlapped those recorded in both diluted BP and PBS samples with no protein. This indicated that saliva components did not cause substantial interference in the detection process, which also agrees with recent literature reports [62] . The concentration of SARS-CoV-2 SP in the saliva samples was quantified using the calibration plot in Fig.…”

Using wide biological pores to cap and contain the COVID-19 spike protein

“…As long as these antibodies do not block the pore or otherwise adversely impact the pore the latter's ability to cap and contain the spike will likely remain unaffected. 8) Other electrochemical methods for detection of the SARS-Cov-2 have been reported recently; see [43] for example. 9) A cap-and-contain approach somewhat like the one described above has been used earlier in a study of Huntingdon disease in which aggregation of a mutant protein (mHTT) is inhibited by a chaperonin complex (TriC), which caps the tips of HTT fibrils and encapsulates mHTT oligomers [44].…”

SARS-CoV-2 Surveillance in Indoor Air Using Electrochemical Sensor for Continuous Monitoring and Real-Time Alerts

“…The methodology of the UFC-19 sensor has been described in previous publications by Ramanujam and Botte [ 15 , 16 ]. In this work, a redesign of the three-electrode UFC-19 sensing device was implemented with a miniaturized rotating disk electrode setup (mRDE) as shown in Figure 6 a.…”

“…This paper presents a pragmatic and novel approach of real-time detection of SARS-CoV-2 in air samples using an Ultra-fast COVID-19 Diagnostic Sensor (UFC-19) [ 15 , 16 ]. In this method SARS-CoV-2 is collected from air and delivers SARS-CoV-2 virions in deionized water (DI) water.…”

“…In this method SARS-CoV-2 is collected from air and delivers SARS-CoV-2 virions in deionized water (DI) water. The water samples are analyzed for SARS-CoV-2 using the UFC-19, that enables detection of the virus within seconds [ 15 , 16 ]. Appropriate air sampling methods are crucial for effective air monitoring.…”