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    • Hepatitis C virus HCV is a frequent cause

    2022-01-07

    Hepatitis C virus (HCV) is a frequent cause of infectious chronic hepatitis. Unlike hepatitis A and B, there is no vaccine to prevent hepatitis C infection yet. According to WHO, around 200 million people are infected with HCV worldwide [1], in addition to three to four million newly infected patients are detected each year. In 2009, Egyptian Demographic and Health Survey (EDHS) have reported an overall anti-HCV antibody prevalence of 14.7% of the Egyptian population (excluding the patients that are under 15 or above 60 years old) was positive for the anti-HCV antibody with overall 0.6% new patients getting infected each year. In addition, Egypt has the highest prevalence of HCV in the world [2]. Therefore, HCV becomes a public health concern for Egyptians. HCV could cause several risks for human health including chronic effects that damage the liver and lead to liver failure. An accurate and early diagnosis of active HCV infection is critical not only because of its associated morbidity and mortality but also because the early diagnosis is the most important factor for successful treatment [3]. Several techniques such as enzyme-linked immunoassays (ELISA), recombinant immune blot assays (RIBA), Surface Plasmon Resonance, electrochemiluminescence, piezoelectric genosensor, cell-based assays, a biosensor based on fluorescence detection, and electrochemical detection were used for detecting anti-HCV asa med [[4], [5], [6], [7]]. However, early detection of HCV using these methods is not feasible due to the absence of antibodies against HCV-antigens at early stages of the disease; in addition, the testing for anti-HCV antibodies couldn't differentiate between the current or past infection [8,9]. Several commercial assays are available for the detection of anti-HCV antibodies [[10], [11], [12]]. Although, the anti-HCV test has significantly reduced the risk of HCV transmission, the time frame for detection of infection remains a concern. The anti-HCV antibodies can be detected 7–8 weeks after infection and usually persist for life. Also, false negative results may arise in immunocompromised patients, such as those with human immunodeficiency virus (HIV) infection or uremia. Therefore, a highly sensitive and reliable test is needed for the early detection of HCV infection. In addition, Reverse transcriptase polymerase chain reaction (RT-PCR) and branched DNA-based assays were used for quantitative detection of HCV with high sensitivity and specificity. However, they are time-consuming, labor intensive, expensive, and require specialized equipment. Nucleic acid testing (NAT) for HCV RNA was developed as a more accurate method for the disease diagnosis and monitoring, as well as a confirmatory diagnostic tool for anti-HCV assays [13,14]. The introducing of NAT has greatly reduced the risk of HCV transmission. But, it is costly, liable to environmental contamination, and laborious work has hampered the wide application of NAT in clinical settings. However, the detection of HCV RNA is too expensive and labor-intensive for routine use. In view of these limitations, there is a need to develop a low-tech assay for the direct detection of unamplified HCV-RNA with high sensitivity, selectivity, short turnaround time, and cost-effectiveness. Electrochemical HCV-biosensors have many advantages in comparing with other molecular detection methods, the advantages including the high sensitivity, its capability to analyze a complicated matrix in addition a compact device and a low power are needed [[15], [16], [17]]. Riccardi et al. have reported a label-free DNA hybridization electrochemical method for detection of HCV [18] by using a film of polypyrrole modified Pt microelectrodes. In addition, Cai's group have developed an HCV-biosensor based on immobilization of DNA-thiol (DNA-SH) onto Au electrode in the presence of thionine as an electrochemical indicator [19,20]. Furthermore, Pournaghi-Azar et al., (2009) has reported the immobilization of DNA on a pencil graphite electrode to detect HCV 1a genotype [21]. Recently, nanoparticles (NPs) have emerged as promising tools with potential applications in many fields such as biosensing and drug delivery. Due to the unique properties of NPs and their ability to interact with biomolecules, several NPs showed a great promise to meet the rigorous criteria of early disease diagnosis and treatment [10]. In this regard, researchers' efforts have especially concentrated on developing nano-biosensors that provide rapid detection by responding to their target with high sensitivity and selectivity. Liu et al. have reported on the development of an electrochemical HCV RNA level for HCV 1b genotype based on the specific DNA modified gold nanoparticles (Au NPs) [22].