An Enzyme Linked ImmunoMagnetic Electrochemical assay (ELIME) was developed for the detection of the hepatitis A virus (HAV). This system is based on the use of new polydopamine-modified magnetic nanobeads as solid support for the immunochemical chain, and an array of 8 screen-printed electrodes as a sensing platform. Enzymatic-by-product is quickly measured by differential pulse voltammetry. For this purpose, all analytical parameters were optimized; in particular, different blocking reagents were evaluated in order to minimize the nonspecific interaction of bioreagents. Using the ELIME assays, a quantitative determination of HAV can be achieved with a detection limit of 1·10-11 IU mL-1 and a working range between 10-10 - 5 × 10-7 IU mL-1. The cross-reactivity of the commercial monoclonal antibodies against HAV used in ELIME assays was tested for Coxsackie B4, resulting very low. The sensitivity was also investigated and compared with spectrophotometric sandwich ELISA. The average relative standard deviation (RSD) of the ELIME method was less than 5% for the assays performed on the same day, and 7% for the measurements made on different days. The proposed system was applied to the cell culture of HAV, which title was quantified by Real-Time Quantitative Reverse Transcription PCR (RT¬qPCR). To compare the results, a correlation between the units used in ELIME (IU mL-1) and those used in RT¬qPCR (genome mL-1) was established using a HAV-positive sample, resulting in 1 IU mL-1-10-4 gen mL-1 (R2 = 0.978). The ELIME tool exhibits good stability and high biological selectivity for HAV antigen detection and was successfully applied for the determination of HAV in tap water.
Keywords: ELIME; Food; Hepatitis A virus; Polydopamine-modified magnetic nanobeads; Screen printed electrodes.
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