Kashefi-Kheyrabadi et al. future application in point-of-care settings are also highlighted. Keywords:COVID-19 diagnosis, biosensors, SARS-CoV-2, RT-qPCR, COVID-19 biomarkers == 1. Introduction == Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first recognized in China, and has grown into a jeopardizing pandemic [1,2]. SARS-CoV-2 is an enveloped, positive-sense, single-stranded genomic RNA (2632 kb) computer virus. The viral envelope is mainly composed of three proteins. The spike (S) glycoprotein, found on the surface, consists of S1 and S2, and holds the receptor-binding domain name (RBD) for ACE2 (angiotensin-converting enzyme 2). The envelope (E) protein is responsible for viral assembly, release, and pathogenicity [3]. The membrane (M) protein organizes the assembly and designs the envelope [4]. It Vatalanib free base aids in morphogenesis and budding and carries immunogenic properties [5]. SARS-CoV-2 is usually primarily transmitted in droplets. After entering the respiratory tract, S-proteins RBD binds to ACE2 around the epithelium. ACE2 receptors are widely present in human tissues, especially in the respiratory and gastrointestinal tracts [6]. Cellular proteases cleave spike proteins from your viral envelope, likely to facilitate membrane fusion and internalization of the viral genome. Viral RNA and proteins are expressed within the cytoplasm, allowing virion synthesis and exocytosis. Eventually, the cellular stressors and the immune response result in the apoptosis of the host cell. This causes immune dysregulation, driving hypercytokinemia, mucus buildup, and airway hyperplasia [7], creating the vintage clinical presentation of COVID-19fever, dry cough, dyspnea, and fatigue. Moreover, SARS-CoV-2 may compromise other tissues such as the heart, kidneys, liver, eyes, and nervous system. SARS-CoV-2s asymptomatic incubation period is usually 27 days, whereby contamination may spread [8]. Most treatments for SARS-CoV-2 focus on curbing its progression, while otherssuch as the antiviral medications Remdesivir (Veklury), Paxlovid, and Molnupiravirpromote recovery of the milder symptoms. REGN-COV2 (Casirivimab and Imdevimab), a cocktail of two noncompeting IgG1 antibodies, also shows capacity to lower viral weight and hospitalization [9]. Additionally, dexamethasone is usually strongly recommended by the National Institutes of Health (NIH) COVID-19 Treatment Guidelines Panel in hospitalized patients who require supplemental oxygen or mechanical ventilation. If corticosteroids cannot be used, baricitinib plus remdesivir may be used in nonintubated patients [9]. One of the cheapest and quickest ways to screen for COVID-19 is usually by clinical presentation, such as temperature measurement [10,11]. Measuring heat is usually by no means specific, but its convenience has allowed for its use in public places to aid in the isolation of sick patients [11]. Imaging has also been used in the diagnosis of COVID-19. It predominantly shows bilateral, diffuse, peripheral abnormalities, ground glass opacities (GGOs), and consolidation in CT and X-ray. Vatalanib free base These signs appear to play a determinant role in patient prognosis and may signal a more severe disease [12,13,14,15]. It is also useful in screening patients and for follow-up after recovery [12]. However, it has low specificity, shown by the relatively indistinguishable nature of COVID-19 images compared to SARS-CoV and MERS [12]. Alternatively, serum analyses can also aid in diagnosis. Patients generally present with lymphopenia, leukocytosis, elevated CRP, and indicators of coagulopathies, though enzymes such as LADH, ALT, and AST can also be elevated [16,17,18]. Although these markers are nonspecific to inflammatory diseases, they can aid in the management and prognosis of patients [16,17]. This review aims to shed light on updates regarding the development of biosensors in the diagnosis of COVID-19, and how they offer potential as a cheaper, faster, and more convenient diagnostic tool compared to standard methods. == 2. Standard Methods for Detecting SARS-CoV-2 == The most specific means for the diagnosis of SARS-CoV-2 contamination is usually through biomarker detection [10]. Currently, the gold standard diagnostic method for SARS-CoV-2 is usually using enzyme-mediated amplification of specific genomic materials, Vatalanib free base such as DNA and RNA. The aim of Reverse Transcription Polymerase Chain Reaction (RT-PCR) is usually to Vatalanib free base detect the viral RNA, in which the RNA is usually reverse Bnip3 transcribed to complementary DNA (cDNA); then, the cDNA is usually amplified and, in qRT-PCR, quantified, as depicted inFigure 1. Commercially available COVID-19 PCR packages target the conserved regions of RdRp, E, N, or ORF1 genomic sequences. PCR assessments are a highly sensitive, specific, and reliable method for clinical application. This method can detect as low as 0.689 copies/L [19]. However, it takes a long time to obtain the results (one.
