Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 2 de 2
Add filters

Document Type
Year range
Talanta ; : 124701, 2023.
Article in English | ScienceDirect | ID: covidwho-2324697


Fast and effective diagnosis is the first step in monitoring the current coronavirus 2 (CoV-2) pandemic. Herein, we establish a simple and sensitive electrochemical assay using magnetic nanocomposite and DNA sandwich probes to rapidly quantify the CoV-2 nucleocapsid (N) gene down to the 0.37 fM level. This assay uses a pair of specific DNA probes. The capture probe is covalently conjugated to Au-decorated magnetic reduced graphene oxide (AMrGO) nanocomposite for efficiently capturing target RNA. In contrast, the detection probe is linked to peroxidase for signal amplification. The probes target the COV-2 gene, allowing for specific magnetic separation, enzymatic signal amplification, and subsequent generation of voltammetric current with a total assay time of 45 min. The developed biosensor has high selectivity and can discriminate non-specific gene sequences. Synthetic COV-2 N-gene can be detected efficiently in serum and saliva, while 1-bp mismatch gene yielded a low response. The performance of the genosensor was good in an extensive linear range of 5 aM–50 pM. For synthetic N-gene, we achieved the detection limit of 0.37, 0.33, and 0.19 fM in human saliva, urine, and serum. This simple, selective, and sensitive genosensor could have various genetics-based biosensing and diagnostic applications.

Mikrochim Acta ; 189(4): 168, 2022 04 01.
Article in English | MEDLINE | ID: covidwho-1767504


The rapid spread of the novel human coronavirus 2019 (COVID-19) and its morbidity have created an urgent need for rapid and sensitive diagnostics. The real-time polymerase chain reaction is the gold standard for detecting the coronavirus in various types of biological specimens. However, this technique is time consuming, labor intensive, and expensive. Screen-printed electrodes (SPEs) can be used as point-of-care devices because of their low cost, sensitivity, selectivity, and ability to be miniaturized. The ability to detect the spike protein of COVID-19 in serum, urine, and saliva was developed using SPE aided by magnetic beads (MBs) and a portable potentiostat. The antibody-peroxidase-loaded MBs were the captured and catalytic units for the electrochemical assays. The MBs enable simple washing and homogenous deposition on the working electrode using a magnet. The assembly of the immunological MBs and the electrochemical system increases the measuring sensitivity and speed. The physical and electrochemical properties of the layer-by-layer modified MBs were systematically characterized. The performance of these immunosensors was evaluated using spike protein in the range 3.12-200 ng mL-1. We achieved a limit of detection of 0.20, 0.31, and 0.54 ng mL-1 in human saliva, urine, and serum, respectively. A facile electrochemical method to detect COVID-19 spike protein was developed for quick point-of-care testing.

Biosensing Techniques , COVID-19 , Biosensing Techniques/methods , COVID-19/diagnosis , Electrodes , Humans , Immunoassay , Magnetic Phenomena , Point-of-Care Testing , Spike Glycoprotein, Coronavirus