Nano-biosensors for Diagnosing Infectious and Lifestyle-Related Disease of Human: An Update

At present time, a variety of infectious and lifestyle diseases are becoming lifethreatening day by day. Development in technology and immergence of nanoscience helped to provide a better health care system. Based on the working mechanism nano-biosensors are of majorly two types: electrochemical nanobiosensor and optical nano-biosensor. Nanomaterials used in the nano-biosensor increased their efficacy, sensitivity, and selectivity of the device. Different diseases have different biomarkers to get detected such as, absorption of cholesterol oxidase detect cholesterol, glaucoma in a diabetes patient is detected by cytokine Interleukin 12 in tear, C-reactive protein is detected for liver inflammation, the SARS virus is detected by N-protein and miRNA is a potential biomarker of cancers, especially colorectal cancer. Hitherto, identification of a biomarker for a specific disease is the major work. The accuracy of nanobiosensor in diagnosing diseases put them in demand in the biomedical field. But the major drawback comes with the cost-effectiveness and use of nanomaterial in health sectors focussing on any toxicological impact of the nano-biosensor on health in long run. In this chapter, we present an overview of the working mechanism of different nano-biosensors in diagnosing different infectious and lifestyle diseases. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023.

Electrochemical immunosensor for diagnosis of COVID-19

An immunosensor is a biosensor that detects antigen interactions using a particular antibody bound on the transducer's surface. These biosensors have high selectivity and sensitivity due to their interaction specificity. Owing to this characteristic, this type of sensor is attractive for several applications, especially in the medical area and bioanalysis. Among the types of immunosensors, electrochemical immunosensors have gained prominence due to their simplicity and portability, potentially enabling in situ detection as promising characteristic for analysis in emergency care. In this chapter, the potential of electrochemical immunosensors is presented, especially in applications related to clinical examinations and mainly in the diagnosis of SARS-CoV-2. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023. All rights reserved.

Trends in electroanalytical assays for COVID-19 diagnosis

The use of electrochemical biosensors is highlighted for SARS-CoV-2 detection and COVID-19 diagnosis. In a brief description of virus structure, fundamental features of proteins and nucleic acid are approached for a comprehensive strategy over biosensor designs. Relevant works are described and related to specific structural proteins used as viral biomarkers. Furthermore, the challenges and perspectives are pointed to the evolution of electroanalysis and the establishment of methods comparable to the gold standard, RT-PCR. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023. All rights reserved.

Microfluidic devices with electrochemical detection towards Covid-19 detection

Over the decades, scientists have made efforts to enhance the performance of analytical procedures whether by creating simpler and faster assays, eliminating unnecessary/laborious steps or by improvements on hardware setup. In this context, microfluidics is the science related to manipulation and control of fluids physically constrained to submillimeter dimensions. This field emerged due to the use of microfabrication techniques for microelectronics purposes such as microchips and microcircuits. As an immediate consequence, the miniaturization of components either by creating new types of microstructures or recreating existing structures (e.g. channels, valves, storage containers, pumps, couplers,) allows the possibility of an entire laboratory in a single micro-sized device (Squires and Quake in RMP 77:977-1026, 2005 1), performing remarkable tasks in biological and chemical (Chiu et al. in Chem 2:201-223, 2017;Alam et al. in Anal Chim Acta 1044:29-65, 2018;Velve-Casquillas et al. in Nano Today 5:28-47, 2010 [2-4]) analysis. Especially for analytical chemistry, a direct consequence of the miniaturization of hardware dimensions impact on less consumption of reagents and minimum sample amount, typically nano or picoliter volumes and hence reduction of chemical waste. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023. All rights reserved.

Using Nanomaterials for SARS-CoV-2 Sensing via Electrochemical Techniques.

Advancing low-cost and user-friendly innovations to benefit public health is an important task of scientific and engineering research. According to the World Health Organization (WHO), electrochemical sensors are being developed for low-cost SARS-CoV-2 diagnosis, particularly in resource-limited settings. Nanostructures with sizes ranging from 10 nm to a few micrometers could deliver optimum electrochemical behavior (e.g., quick response, compact size, sensitivity and selectivity, and portability), providing an excellent alternative to the existing techniques. Therefore, nanostructures, such as metal, 1D, and 2D materials, have been successfully applied in in vitro and in vivo detection of a wide range of infectious diseases, particularly SARS-CoV-2. Electrochemical detection methods reduce the cost of electrodes, provide analytical ability to detect targets with a wide variety of nanomaterials, and are an essential strategy in biomarker sensing as they can rapidly, sensitively, and selectively detect SARS-CoV-2. The current studies in this area provide fundamental knowledge of electrochemical techniques for future applications.

Impedimetric Sensing: An Emerging Tool for Combating the COVID-19 Pandemic.

The COVID-19 pandemic revealed a pressing need for the development of sensitive and low-cost point-of-care sensors for disease diagnosis. The current standard of care for COVID-19 is quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). This method is sensitive, but takes time, effort, and requires specialized equipment and reagents to be performed correctly. This make it unsuitable for widespread, rapid testing and causes poor individual and policy decision-making. Rapid antigen tests (RATs) are a widely used alternative that provide results quickly but have low sensitivity and are prone to false negatives, particularly in cases with lower viral burden. Electrochemical sensors have shown much promise in filling this technology gap, and impedance spectroscopy specifically has exciting potential in rapid screening of COVID-19. Due to the data-rich nature of impedance measurements performed at different frequencies, this method lends itself to machine-leaning (ML) algorithms for further data processing. This review summarizes the current state of impedance spectroscopy-based point-of-care sensors for the detection of the SARS-CoV-2 virus. This article also suggests future directions to address the technology's current limitations to move forward in this current pandemic and prepare for future outbreaks.

Design of a rapid electrochemical biosensor based on MXene/Pt/C nanocomposite and DNA/RNA hybridization for the detection of COVID-19.

Since the rapid spread of the SARS-CoV-2 (2019), the need for early diagnostic techniques to control this pandemic has been highlighted. Diagnostic methods based on virus replication, such as RT-PCR, are exceedingly time-consuming and expensive. As a result, a rapid and accurate electrochemical test which is both available and cost-effective was designed in this study. MXene nanosheets (Ti3C2Tx) and carbon platinum (Pt/C) were employed to amplify the signal of this biosensor upon hybridization reaction of the DNA probe and the virus's specific oligonucleotide target in the RdRp gene region. By the differential pulse voltammetry (DPV) technique, the calibration curve was obtained for the target with varying concentrations ranging from 1 aM to 100 nM. Due to the increase in the concentration of the oligonucleotide target, the signal of DPV increased with a positive slope and a correlation coefficient of 0.9977. Therefore, at least a limit of detection (LOD) was obtained 0.4 aM. Furthermore, the specificity and sensitivity of the sensors were evaluated with 192 clinical samples with positive and negative RT-PCR tests, which revealed 100% accuracy and sensitivity, 97.87% specificity and limit of quantification (LOQ) of 60 copies/mL. Besides, various matrices such as saliva, nasopharyngeal swabs, and serum were assessed for detecting SARS-CoV-2 infection by the developed biosensor, indicating that this biosensor has the potential to be used for rapid Covid-19 test detection.

GlycoEVLR: Glycosylated extracellular vesicle-like receptors for targeting and sensing viral antigen

Biosensors are rapid and portable detection devices with great potential for the instant screening of infectious diseases. Receptors are the critical element of biosensors. They determine the specificity, sensitivity and stability. However, current receptors are mainly limited to antibodies and aptamers. Herein, we developed a glycosylated extracellular vesicle-like receptor (GlycoEVLR) for the rapid detection of virus antigens, specifically using SARS-CoV-2 as a model. The human angiotensin-converting enzyme 2 (ACE2)-overexpressed and heparin-functionalized HEK-293T cell membrane-cloaked Fe3O4 nanoparticles (NPs) were prepared as functionalizing GlycoEVLR. They were characterized as spherical core–shell structures with a diameter of around 100 nm, which were perfectly comparable to natural extracellular vesicles. Binding affinities between GlycoEVLR and spike1 (S1) antigen were demonstrated using surface plasmon resonance (SPR). The GlycoEVLR was fixed on magnetic electrodes to construct electrochemical biosensors. Using electrochemical impedance spectroscopy (EIS) as a measurement technique, the S1 antigen was detected down to 1 pg/mL within 20 min and showed a good linearity range from 1 pg/mL to 1 ng/mL. Also, the GlycoEVLR-based electrochemical biosensors showed excellent antifouling performance and stability. Overall, our work provides a useful methodology for developing extracellular vesicle-like receptors for biosensors. Combining the inherit natural receptor proteins and antifouling lipids from the host cells with engineered glycan motifs to target and sense viral antigens will open a newavenue for biosensors.

Copper-free click chemistry assisted antibodies for immunodetection of interleukin-10 in saliva

Interleukin-10 (IL-10) is an anti-inflammatory cytokine that is secreted in response to an acute phase inflammation in patients who are suffering from heart failure (HF). The aim of this work was to develop an electrochemical biosensor for determining salivary IL-10 levels. Biofunctionalization strategy was improved through the use of copper-free click chemistry for the developed sensor due to its advantages, leading to high quantitative yields of stable triazoles, rapid reaction, no cytotoxic Cu(I) catalyst requirement, and high specificity of cyclooctynes toward azides. The approach involved in binding of dibenzocyclooctyne acid (DBCO-COOH) to thiol-azide assembled gold microelectrodes, later capturing the monoclonal IL-10 antibody (IL-10 mAb), and ultimately allowing direct detection of IL-10 antigen. Fourier transform infrared spectroscopy (FTIR) and nanoplotter associated with fluorescence microscopy methods have been employed to analyze and prove the biofunctionalization of the gold microelectrodes. Moreover, the electrochemical impedance spectroscopy (EIS) technique was used for detecting IL-10 antigen. The developed immunosensor showed a semi-logarithmic linear range, from 0.1 pg/mL to 5 pg/mL with R2 = 0.9815 and a limit of quantitation (LOQ) of 0.1 pg/mL with relative standard deviation (RSD) of 10.67%. The specificity of the immunosensor was evaluated using an inflammatory cytokine, and none of it generated detectable EIS signals. Finally, the successful analysis of saliva samples from a healthy volunteer without Coronavirus (COVID-19) infection demonstrated the usefulness of the developed immunosensor.

Uniform Gold Nanostructure Formation via Weakly Adsorbed Gold Films and Thermal Annealing for Reliable Localized Surface Plasmon Resonance-Based Detection of DNase-I.

Deoxyribonuclease-I (DNase-I), a representative endonuclease, is an important biomarker for the diagnosis of infectious diseases and cancer progression. However, enzymatic activity decreases rapidly ex vivo, which highlights the need for precise on-site detection of DNase-I. Here, a localized surface plasmon resonance (LSPR) biosensor that enables the simple and rapid detection of DNase-I is reported. Moreover, a novel technique named electrochemical deposition and mild thermal annealing (EDMIT) is applied to overcome signal variations. By taking advantage of the low adhesion of gold clusters on indium tin oxide substrates, both the uniformity and sphericity of gold nanoparticles are increased under mild thermal annealing conditions via coalescence and Ostwald ripening. This ultimately results in an approximately 15-fold decrease in LSPR signal variations. The linear range of the fabricated sensor is 20-1000 ng mL-1 with a limit of detection (LOD) of 127.25 pg mL-1 , as demonstrated by spectral absorbance analyses. The fabricated LSPR sensor stably measured DNase-I concentrations from samples collected from both an inflammatory bowel disease (IBD) mouse model, as well as human patients with severe COVID-19 symptoms. Therefore, the proposed LSPR sensor fabricated via the EDMIT method can be used for early diagnosis of other infectious diseases.

Direct Quantitation of SARS-CoV-2 Virus in Urban Ambient Air via a Continuous-Flow Electrochemical Bioassay.

Airborne SARS-CoV-2 virus surveillance faces challenges in complicated biomarker enrichment, interferences from various non-specific matters and extremely low viral load in the urban ambient air, leading to difficulties in detecting SARS-CoV-2 bioaerosols. This work reports a highly specific bioanalysis platform, with an exceptionally low limit-of-detection (≤1 copy m-3 ) and good analytical accordance with RT-qPCR, relying on surface-mediated electrochemical signaling and enzyme-assisted signal amplification, enabling gene and signal amplification for accurate identification and quantitation of low doses human coronavirus 229E (HCoV-229E) and SARS-CoV-2 viruses in urban ambient air. This work provides a laboratory test using cultivated coronavirus to simulate the airborne spread of SARS-CoV-2, and validate that the platform could reliably detect airborne coronavirus and reveal the transmission characteristics. This bioassay conducts the quantitation of real-world HCoV-229E and SARS-CoV-2 in airborne particulate matters collected from road-side and residential areas in Bern and Zurich (Switzerland) and Wuhan (China), with resultant concentrations verified by RT-qPCR.

Screening and comparative studies of conducting polymers for developing effective molecular imprinted sensors for copper, zinc superoxide dismutase

This work describes the design, development, and screening of conducting polymers based molecularly imprinting sensors (MIP) for copper, Zinc superoxide dismutase (SOD1). It is clinically significant for a wide variety of cardiovascular, neurodegenerative, Covid-19, and chronic immune illness. The SOD1 MIP sensors were undertaken by electropolymerization of various monomers on Screen Printed carbon electrode (SPCE) using cyclic voltammetry (CV) to examine the molecular recognition capability. The MIP receptors film binding towards SOD1 was studied by fitting experimental CV data to the Langmuir and Freundlich isotherms. Among the various monomers EDOT (3,4-ethylenedioxythiophene), Py (Pyrrole), and DA (Dopamine), the binding affinity (KL) of the poly(3-amionphenylboronic acid) (P3APBA) imprinted MIP system was considerably higher than the other conducting polymer MIP systems. Based on the above studies, 3APBA was chosen to develop a molecularly imprinted poly(3-aminophenylboronic acid) (MIP3APBA) sensor for sensitive and selective detection of SOD1. This MIP3APBA sensor's behaviour and analytical ability were characterized by Cyclic Voltammetry (CV), Differential Pulse Voltammetry (DPV) and Electrochemical Impedance Spectroscopy (EIS). It showed a lowest detection limit of 0.4 μM and a linear range of 1 μM to 500 μM. Further, this electrochemical MIP3APBA sensor was also used to quantify SOD1 levels in plasma samples.

Sensitive Detection of SARS-CoV-2 Spike Protein based on Electrochemical Impedance Spectroscopy of Fe3O4@SiO2-Au/GCE Biosensor

Highly contagious COVID-19 disease is caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which poses a serious threat to global public health. Therefore, the development of a fast and reliable method for the detection of SARS-CoV-2 is an urgent research need. The Fe3O4@SiO2-Au is enriched with a variety of functional groups, which can be used to fabricate a sensitive electrochemical biosensor by biofunctionalization with angiotensin-converting enzyme 2 (ACE2). Accordingly, we developed a novel electrochemical sensor by chemically modifying a glassy carbon electrode (GCE) with Fe3O4@SiO2-Au nanocomposites (hereafter Fe3O4@SiO2-Au/GCE) for the rapid detection of S-protein spiked SARS-CoV-2 by electrochemical impedance spectroscopy (EIS). The new electrochemical sensor has a low limit detection (viz., 4.78 pg/mL) and a wide linear dynamic range (viz., 0.1 ng/mL to 10 μg/mL) for detecting the EIS response signal of S-protein. The robust Fe3O4@SiO2-Au/GCE biosensor has high selectivity, stability, and reproducibility for the detection of S-protein with good recovery of saliva samples.

Importance of IP-10 as a biomarker of host immune response: Critical perspective as a target for biosensing

While the exploration into biomolecules for diagnostic and prognostic devices continues to develop, many molecules continue to be examined for individual diseases or treatments. Consequently, it can be difficult to fully understand the scope of one individual molecule's current and potential clinical utilization. The scope of this study aimed to assess the potential of Interferon Gamma-induced Protein 10 (IP-10) as a biomarker in a wide variety of diseases, both as a main and supplemental indicator of disease infection and progression. IP-10 is a chemokine secreted in response to IFN-gamma playing a major role in the activation and regulation of inflammatory and immune responses within the body. Currently, IP-10 has displayed potential application in diseases such as COVID-19, tuberculosis, sepsis, Kawasaki disease, cancer, and many more. Molecular assays developed for the detection of IP-10 take longer testing time, sophisticated instrument utilization, and need more sample volumes. These cannot be utilized for bedside patient monitoring during the illness state of the patient. Biosensing tools are alternative methods used at clinical sites due to their rapid results. Though many types of sensing mechanisms established for the detection of disease biomarkers such as optical, piezoelectric sensors, and electrochemical biosensors are far beyond the other sensing methods due to their ease of mechanism, rapid results, and portable nature. IP-10 has been a promising biomarker in different diseases, evaluation of IP-10 levels at different time points of treatments is necessary. To achieve this, current conventional methods cannot be used and thus a portable device that provides rapid results is in demand. Such point-of-care (POC) device development for IP-10 analysis is very crucial in the current scenario. Beyond this, the clarification of its physiological role in healthy and infected individuals could allow for more proper utilization in clinical diagnoses, prognoses, treatment monitoring, and more. Overall, this study was developed to summarize the associations currently created between levels of IP-10 and other biomolecules and diseases.Copyright © 2023 The Author(s)

Trans/feminist collaborative autoethnographic storying of gender-based violence, during the COVID-19 pandemic

In this paper, we reported on the lattice distortion, surface morphologies, vacancy defects and electrochemical performance that had been observed in Na3V2(PO4)2F3 prepared at different annealing temperatures. X-ray diffraction indicated that all the samples were single phase materials with tetragonal structure and exhibited lattice distortion with the increase of annealing temperatures. A possible mechanism causing the strain-induced lattice distortion had been discussed. Moreover, scanning electron microscopy and positron annihilation techniques were used to study the grain size and vacancy defects as a function of annealing temperatures. The superior electrochemical performance of Na3V2(PO4)2F3 electrode was obtained at the annealing temperature of 350 degrees C with 167.73 F center dot g-1 specific capacitance and 85% capacitance retention. The better electrochemical performance was due to the synergistic effects of grain size and vacancy defect regulated by the annealing temperatures. These results could provide experimental basis for enhancing electrochemical performance of Na3V2(PO4)2F3 in sodium-ion battery area applications. (c) 2023 Elsevier B.V. All rights reserved.

Synthesis and characterization of Au-decorated graphene oxide nanocomposite for magneto-electrochemical detection of SARS-CoV-2 nucleocapsid gene.

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.

Evaluating the quality consistency of antiviral oral liquid by high-performance liquid chromatography five-wavelength matched average fusion fingerprint combined with electrochemical fingerprint and ultraviolet spectral quantum fingerprint.

The antiviral oral liquid (AOL) was an antiviral drug currently in clinical trials against coronavirus disease 2019. This study aimed to improve its quality consistency evaluation method using fingerprint techniques from several aspects. First, the five-wavelength matched average fusion fingerprint (FMAFFP) for HPLC, electrochemical fingerprint (ECFP), and ultraviolet spectral quantum fingerprint (UVFP) was established for 22 samples, respectively. Their quality was then assessed using the average linear quantitative fingerprint method, and 22 samples were classified into eight quality grades. OPLS and PCA were then used further to explore the characteristic parameters of these three fingerprints. Five compounds were quantified simultaneously for the first time, and then the relationship between the average linear quantitative similarity (PL) and the sum of the five quantitative components (P5c) was investigated. A linear correlation (r ≥ 0.9735) between PL and P5c suggested that PL may be used to predict chemical content. Finally, to investigate the antioxidant potential of the AOL, correlation analyses were performed for FMAFFP peaks-PEC and UVFP peaks-PEC, respectively, where the PEC value was defined as the quantitative similarity of ECFP. The Pearson correlation coefficient and gray correlation analysis were consistent, allowing us to initially explore the antioxidant capacity of the unidentified components of the samples. This study researched AOL using multidimensional fingerprints to provide a comprehensive and reliable method for quality consistency control of herbal compound preparations.

Bifunctional three-way DNA junction-based strand displacement recycling for amplifiable electrochemical bivariate biosensing

It's intriguing to utilize the branched arms of three-way DNA junction (3WDJ) for modifying specific recognizing and/or sensing elements of multivariate analytes. Herein, by using two targeting DNA segments (T and T*) specific to SARS-CoV-2 as analyte models, an electrochemical bivariate biosensor was created based on a functional 3WDJ including two -NH2-labeled recognizable probes (RP and RP*) and an assistant probe (AP), while its two branched arms hybridized with four helping DNA blockers. In the electrode surface electrodeposited in HAuCl4, the 3WDJ was stably immobilized via Au-N bonds to specifically recognize and bind T and T*, with which two modified signaling probes by electroactive methylene blue (SP-MB) and ferrocene (SP*-Fc) were introduced to initiate two strand displacement reactions. Resultantly, SP-MB and SP*-Fc were guided to be complementarily hybridized in two arms of 3WDJ, replacing T and T* to execute two individual repeatable recycling for signal amplification. Thus, MB and Fc were oriented proximal to the modified electrode surface for significantly increased electrochemical current signals, respectively dependent on T and T*. With the branched arms of rapidly assembled 3WDJ, the discernible detection of bivariate targets was achievable, showing superb simplification, high sensitivity, and potentially more accurate electrochemical assay of multivariate targets. Data Availability Data will be made available on request.

In Situ Electrochemical Trapping and Unraveling the Mechanism of the Toxic Intermediate Metabolite N-Acetyl-p-Benzoquinone Imine of the Acetaminophen Drug and Its Biomimetic Mediated NADH Oxidation Reaction

The integrative study of the pharmacokinetics and dynamics of a drug has been of great research interest due to its authentic description of the biomedical and clinical pros and cons. Acetaminophen (N-acetyl-4-aminophenol, AcAP) is a well-known analgesic having a high therapeutic value, including the Covid-19 treatment. However, an overdose of the drug (>200 mg/kg of men) can lead to liver toxicity. An intermediate, N-acetyl-p-benzoquinone imine (NAPQI), metabolite formation has been found to be responsible for the toxicity. For the detection of NAPQI, several ex situ techniques based on electrochemical methods followed by nuclear magnetic resonance, high-performance liquid chromatography, and LC-MS were stated. For the first time, we report an in situ electrochemical approach for AcAP oxidation and NAPQI intermediate (Mw = 149.1 g mol-1) trapping on a graphitic nanomaterial, carbon black (CB)-modified electrode in pH 7 phosphate buffer solution (CB@NAPQI). The NAPQI-trapped electrode exhibited a surface-confined redox peak at E°′ = 0.350 ± 0.05 V vs Ag/AgCl with a surface excess value of 3.52 n mol cm-2. Physicochemical characterizations by scanning electron microscopy, Raman, FTIR, and in situ electrochemical quartz crystal microbalance (EQCM) techniques supported the entrapment of the molecular species. Furthermore, the scanning electrochemical microscopy (SECM) technique has been adopted for surface-mapping the true active site of the NAPQI-trapped electrode. As a biomimetic study, the mediated oxidation reaction of NADH by CB@NAPQI was demonstrated, and the mechanistic and quantitative aspects were studied using cyclic voltammetry, rotating disc electrode, amperometry, and flow injection analysis techniques. © 2023 American Chemical Society.

Development of Aptasensor for the Diagnosis of Covid-19

Objectives: The objective is to develop a low-cost, practical, portable aptasensor platform for the diagnosis of COVID-19. Materials -Methods: Amino-terminated aptamers to be used for the design of an aptasensor were synthesized by SELEX method, and interaction of aptamers with SARS-CoV-2 S1 protein was investigated by isothermal titration calorimetry (ITC). Gold electrodes were used to design the biosensor platform. After the electrode surface was functionalized with cysteamine, the amino-terminated aptamer was conjugated to the surface via glutaraldehyde crosslinker. Then, the surface characterization and analytical parameters of the designed sensing platform were determined by adding commercial S1 proteins on the surface using differential pulse voltammetry (DPV), cyclic voltammetry (CV) and impedance spectroscopy (EIS). To evaluate the working performance of the system, S1 proteins were added to the synthetic serum samples using the standard addition method and the measurements were repeated. Result(s): Surface characterization of the platform designed with EIS and CV measurements was performed and it was found that the modification was successfully performed. In addition, DPV results and analytical parameters of the platform (calibration plot, limit of detection(LOD) , repeatability, coefficient of variation) were determined and the working performance of system was evaluated. Moreover, working performance of the biosensor in real samples and its specificity for COVID -19 were determined by experiments with synthetic serum and influenza A and B proteins. Conclusion(s): According the results, the system has potential to be used for the detection of COVID -19, and also it can be rapidly adapted in different pandemic situations that may occur in the future.