The Reduction of SARS-CoV-2 RNA Concentration in the Presence of Sewer Biofilms

Wastewater surveillance has been widely used to track the prevalence of SARS-CoV-2 in communities. Although some studies have investigated the decay of SARS-CoV-2 RNA in wastewater, understanding about its fate during wastewater transport in real sewers is still limited. This study aims to assess the impact of sewer biofilms on the dynamics of SARS-CoV-2 RNA concentration in naturally contaminated real wastewater (raw influent wastewater without extra SARS-CoV-2 virus/gene seeding) using a simulated laboratory-scale sewer system. The results indicated that, with the sewer biofilms, a 90% concentration reduction of the SARS-CoV-2 RNA was observed within 2 h both in wastewater of gravity (GS, gravity-driven sewers) and rising main (RM, pressurized sewers) sewer reactors. In contrast, the 90% reduction time was 8–26 h in control reactors without biofilms. The concentration reduction of SARS-CoV-2 RNA in wastewater was significantly more in the presence of sewer biofilms. In addition, an accumulation of c.a. 260 and 110 genome copies/cm2 of the SARS-CoV-2 E gene was observed in the sewer biofilm samples from RM and GS reactors within 12 h, respectively. These results confirmed that the in-sewer concentration reduction of SARS-CoV-2 RNA in wastewater was likely caused by the partition to sewer biofilms. The need to investigate the in-sewer dynamic of SARS-CoV-2 RNA, such as the variation of RNA concentration in influent wastewater caused by biofilm attachment and detachment, was highlighted by the significantly enhanced reduction rate of SARS-CoV-2 RNA in wastewater of sewer biofilm reactors and the accumulation of SARS-CoV-2 RNA in sewer biofilms. Further research should be conducted to investigate the in-sewer transportation of SARS-CoV-2 and their RNA and evaluate the role of sewer biofilms in leading to underestimates of COVID-19 prevalence in communities.

Updates of precision medicine in type 2 diabetes

Diabetes mellitus is prevalent worldwide and affects 1 in 10 adults. Despite the successful development of glucose-lowering drugs, such as glucagon-like peptide-1 (GLP-1) receptor agonists and sodium-glucose cotransporter-2 inhibitors recently, the proportion of patients achieving satisfactory glucose control has not risen as expected. The heterogeneity of diabetes determines that a one-size-fits-all strategy is not suitable for people with diabetes. Diabetes is undoubtedly more heterogeneous than the conventional subclassification, such as type 1, type 2, monogenic and gestational diabetes. The recent progress in genetics and epigenetics of diabetes has gradually unveiled the mechanisms underlying the heterogeneity of diabetes, and cluster analysis has shown promising results in the substratification of type 2 diabetes, which accounts for 95% of diabetic patients. More recently, the rapid development of sophisticated glucose monitoring and artificial intelligence technologies further enabled comprehensive consideration of the complex individual genetic and clinical information and might ultimately realize a precision diagnosis and treatment in diabetics.

EUROPE'S ETERNAL STRUGGLE WITH SAFETY AND INNOVATION

Amid the heated COVID-driven controversies over vaccination that are ruffling Europe, a specialized European advisory group on ethics has just issued a cautious opinion on the use of gene editing-including a call for a global guarantee that heritable human genome editing is not prematurely clinically applied. The European Group on Ethics in Science and New Technologies (EGE) is tasked with advising the European Commission with "high quality, independent advice on all aspects of EU legislation and policies, where ethical, societal and fundamental rights issues intersect with the development of science and new technologies." With a view to promoting broad alignment, the group has asked the European Commission to engage in global discussions on regulation of this emerging field with the World Health Organization and the World Medical Association, covering universal adoption of standards on the ethical use of genome editing in human beings. [...]within Europe it wants to see the creation of a specifically European platform to exchange information and promote "a broad and open public debate" on the ethical and social implications of germline genome editing in human beings.

GENETIC PATTERN OF THE COVID-19 COURSE AND REINFECTION

A new coronavirus infection (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) broke out at the end of 2019 in Wuhan (China). The disease has become a global pandemic and claimed more than 6 million lives after spreading rapidly around the world. Issues related to the complicated course of COVID-19 mechanisms continue to be the subject of active study. It is known that morbidity and mortality increase dramatically with increasing age and concomitant diseases, including obesity, diabetes, cancer, and cardiovascular diseases. Although most infected people recover, even young and otherwise healthy patients can get sick with this disease. In this regard, an urgent task is to search for specific genetic factors that can explain the predisposition of people to infection and the development of a severe COVID-19 form. Human genetic determinants can provide the scientific basis for disease prediction and the development of personalized therapies to counteract the epidemic. In addition, cases of repeated infection with SARS-CoV-2 are increasingly being registered, which occurs 1–6 months after initial infection on average and depends on the virus genome structure. Studies conducted on sequencing viral genomes have shown that some patients were re-infected with the same strain of coronavirus, while others were different. This, in turn, causes researchers concerns about the effectiveness of immunity after infection and vaccine reliability. The genetic characteristics of a person and a virus commonly determine the tendency for reinfection. It is difficult to determine the true COVID-19 reinfection prevalence, which is explained by the low detectability of asymptomatic reinfection and the fact that many patients with a mild course of the disease were not tested at an early stage of the pandemic. Therefore, the true prevalence of reinfection with COVID-19 does not reflect the current reality. There are many more cases of reinfection than are described in the literature. In this regard, the true contribution of a virus' genetic features to reinfection of COVID-19 can be determined only after population studies, and when developing immunization programs against a COVID-19, it is necessary to take into account the prevalence of reinfection in the population. The article can be used under the CC BY-NC-ND 4.0 license © Authors, 2022.

Preparing for the next viral threat with broad-spectrum antivirals

There is a large global unmet need for the development of countermeasures to combat hundreds of viruses known to cause human disease and for the establishment of a therapeutic portfolio for future pandemic preparedness. Most approved antiviral therapeutics target proteins encoded by a single virus, providing a narrow spectrum of coverage. This, combined with the slow pace and high cost of drug development, limits the scalability of this direct-acting antiviral (DAA) approach. Here, we summarize progress and challenges in the development of broad-spectrum antivirals that target either viral elements (proteins, genome structures, and lipid envelopes) or cellular proviral factors co-opted by multiple viruses via newly discovered compounds or repurposing of approved drugs. These strategies offer new means for developing therapeutics against both existing and emerging viral threats that complement DAAs.

Natural Evolution of Porcine Epidemic Diarrhea Viruses Isolated from Maternally Immunized Piglets

Simple SummaryDuring the long-term co-evolution of the virus and the host, even closely related vaccines may emerge with incomplete protective immunity due to the mutations or deletions of amino acids at specific antigenic sites. The mutation of PEDV was accelerated by the recombination of different strains and the mutation of the strains adapting to the environment. These mutations either cause immune escape from conventional vaccines or affect the virulence of the virus. Therefore, researching and developing new vaccines with cross-protection through continuous monitoring, isolation and sequencing are important to determine whether their genetic characteristics are changed and to evaluate the protective efficacy of current vaccines. The porcine epidemic diarrhea virus (PEDV) can cause severe piglet diarrhea or death in some herds. Genetic recombination and mutation facilitate the continuous evolution of the virus (PEDV), posing a great challenge for the prevention and control of porcine epidemic diarrhea (PED). Disease materials of piglets with PEDV vaccination failure in some areas of Shanxi, Henan and Hebei provinces of China were collected and examined to understand the prevalence and evolutionary characteristics of PEDV in these areas. Forty-seven suspicious disease materials from different litters on different farms were tested by multiplex PCR and screened by hematoxylin-eosin staining and immunohistochemistry. PEDV showed a positivity rate of 42.6%, infecting the small and large intestine and mesenteric lymph node tissues. The isolated strains infected Vero, PK-15 and Marc-145 multihost cells and exhibited low viral titers in all three cell types, as indicated by their growth kinetic curves. Possible putative recombination events in the isolates were identified by RDP4.0 software. Sequencing and phylogenetic analysis showed that compared with the classical vaccine strain, PEDV SX6 contains new insertion and mutations in the S region and belongs to genotype GIIa. Meanwhile, ORF3 has the complete amino acid sequence with aa80 mutated wild strains, compared to vaccine strains CV777, AJ1102, AJ1102-R and LW/L. These results will contribute to the development of new PEDV vaccines based on prevalent wild strains for the prevention and control of PED in China.

Genetic Vaccine Platforms Demonstrate Their Potential

Challenges with traditional vaccines The potential exists for adverse effects because live viral vaccines are attenuated by genetic mutation of the wild-type, disease-causing virus, either by passaging the virus through cells, eggs, or animals or purposeful deletion of sections of the viral genome, explains Kelly Lyn Warfield, vice president of vaccines research and development within Emergent BioSolutions' Vaccines Business Unit. "For selection and use of live, attenuated viral vaccines, caution must be applied due to potential safety issues in immunocompromised individuals (i.e., primary immunodeficiencies, patients on immunosuppressant treatment, HIV-infected people, and sometimes the very young or old), since this type of vaccine has the potential to replicate in an uncontrolled manner. spread to other individuals due to shedding of the vaccine, or revert to a virulent (disease-causing) form," she says. [...]a viral vector-based vaccine can cause an immune response to the viral vector itself in addition to the antigen of interest for which it is delivering the nucleic acid, according to Gregory Bleck, vice president of research and development at Catalent Biologies. [...]to achieve complete immune protection and to increase its duration, a prime boost dosing regimen in two consecutive vaccinations with the same or a different vaccine may be applied, which is what we're seeing in the mRNA COVID-19 vaccines," he says.

A call for an integrated biology

The Song of the Cell tells the story of how we came to understand ourselves and other complex living organisms as mosaics of these atoms of life. There is the "dividing cell”, which takes us to the 2001 Nobel Prize in Physiology or Medicine that Nurse won, alongside Leland Hartwell and Tim Hunt, for elucidating the roles of cyclin and cyclin-dependent kinase proteins in regulating the cell cycle, and to the invention of reproductive in-vitro fertilisation by Patrick Steptoe and Robert Edwards during the 1970s. Quite what the "new human” of the subtitle refers to is never fully clear, but the ability to reprogramme cell states, as for example, in the method devised by stem-cell researcher Shinya Yamanaka to induce mature somatic cells back to pluripotency, might have the potential to grow organs in vitro, to regenerate tissues in vivo, and even to create synthetic embryo-like structures without the involvement of fertilisation. Mukherjee rightly admits that this view goes too far, but it might at least be understood as suggesting that trying to attack cancer at the genetic level is like hoping to stop traffic jams by fixing the faulty brakes of the car that caused the last one.

Charge Detection Mass Spectrometry: What's the "Big" Deal?

In 2002, the first fully humanized mAb was approved by the U.S. Food and Drug Administration (FDA) (3). [...]the biopharmaceutical industry is still in its infancy and new, more complex products are in development and will ikely dominant the market in the future. [...]the most common forms of LC-MS have limitations when characterizing large macromolecules (4). [...]in this column, we discuss the potential for charge detection MS (CDMS) as an analytical tool for characterizing large, complex, and heterogenous biopharmaceuticals. [...]in October 2021 at the American Association for Mass Spectrometry (ASMS) annua meeting in Philadelphia, TrueMass presented the first commercial CDMS (6,7). The cylinder is often inside an electrostatic linear ion trap (ELIT) instrument, where ions oscillate back and forth. [...]the oscillation frequency gives the m/z and the charge is determined by the magnitude.

Detection of Mutations in SARS-CoV-2 Genomic Clades using COVIDSeq-NGS among International Travelers

Introduction/Objective Numerous SARS-CoV-2 variants/lineages have been identified based on genome sequencing. As of June 15, 2022 almost 11,399,573 whole genome sequences have been deposited in the GISAID-database. Severity and spread of COVID19 is based on their efficiency of infection and to multiply in host. That largely depend upon the structural mutation in spike, ORF and N proteins etc. That happens due to translation of genomic mutations during polypeptide synthesis. Also, the mutations are region/country specific. Specific mutation and combination of mutation causes the emergence of new strains. However, the strains can migrate from one region to other through travelers. The main objective of the current study is profiling of mutations in the genome of SARSCoV2 using Next- Generation-Sequencing (NGS) in international travelers and phylogenetic analysis of the sequences to find out different clades of SARSCoV2. Methods/Case Report A total of 557 SARSCoV2 genomes were sequenced on S4-sequencing flow-cell on NovaSeq 6000. For NGS of SARS-CoV-2 genome, Illumina, COVIDSeq kits and the protocols will be used strictly as recommended by the manufacturer. After NGS the analysis was done followed by FASTA sequences retrieval, mutations recording and phylogeny. Results (if a Case Study enter NA) This study reports 11 clades (19A, B, 20A, B, C, D, 20E;EU1, 20G, 20H;Beta V2, 20I: Alpha V1, 21D;and Eta) for the first time in international travelers. To best of our knowledge, this is the first report of the COVIDSeq approach for detection of mutation in SARSCoV2 genomic clades. The study revealed some dominants mutations was (Orf1a: P2018Q, K1053R, E176V, Orf1b: A520V, T2165A, S: D1127G, D614G, L18F etc. in other genes). Conclusion Profiling of common mutations among travelers could fill some gaps about the existence of SARS-CoV-2 variants information. However, further studies are needed to consolidate these findings before to be utilized for development of a potential therapeutic strategy.

NIH restarts halted bat virus grant

In January, a federal audit found that EcoHealth had misreported nearly $90,000 in expenses for several grants dating to 2014 and that NIH had erred by not justifying its termination (later changed to a suspension) of the 2019 grant. Three years after then-President Donald Trump pressured the U.S. National Institutes of Health (NIH) to shut down a research grant to a group studying how bat coronaviruses jump to people, the agency has restarted the award. [Extracted from the article] Copyright of Science is the property of American Association for the Advancement of Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Newly Characterized Porcine Epidemic Diarrhea Virus GII Subtype Strain

Diarrhea outbreaks in piglets on pig farms are commonly attributed to porcine epidemic diarrhea virus (PEDV) infection. This research analyzed the S gene prevalence variation and recombination patterns in PEDV GII strains. Throughout the previous two years, 172 clinical samples of piglet diarrhea have been collected, from which 24 PEDV isolates have been isolated. Analysis of the evolutionary relationships among all 24 S genes revealed that 21 were most closely related to strains within the GII-a subgroup. The 2 isolates grouped into one clade with the GII-b subgroup. According to the mutation analysis of the amino acids (aa) that encode the S protein, 43 of the common aa in strains of the GII subtype were found to have undergone a change in polarity or charge, and 36 of these aa had a mutation frequency of more than 90%. Three different aa mutation sites were identified as exclusive to GII-a subtype strains. The genomes of three PEDV isolates were sequenced, and the resulting range in genome length was 28,035−28,041 nt. The results of recombination analysis showed that the SD1 isolate is a novel strain recombinant from the foreign S-INDEL strain and a domestic GII subtype strain. Based on the findings, the PEDV GII-a strain has been the most circulating strain in several parts of China during the previous two years. Our study reveals for the first time the unique change of aa mutations in the S protein of the GII-a subtype strain and the new characteristics of the recombination of foreign strains and domestic GII subtype strains, indicating that it is crucial to monitor the epidemic dynamics of PEDV promptly to prevent and control the occurrence of PED effectively.

Molecular Detection and Genetic Characterization of Bovine Kobuvirus (BKV) in Diarrhoeic Calves in a Central Italy Herd

Bovine kobuvirus (BKV) is an infectious agent associated with neonatal calf diarrhoea (NCD), causing important economic losses to dairy and beef cattle herds worldwide. Here, we present the detection rate and characterize the genome of BKV isolated from diarrhoeic calves from a Central Italy herd. From January to December 2021, we collected blood samples and nasal and rectal swabs from 66 calves with severe NCD between 3 and 20 days of age. After virological (bovine coronavirus, bovine viral diarrhoea virus, and bovine rotavirus), bacteriological (Escherichia coli spp. and Salmonella spp.), and parasitological (Cryptosporidium spp., Eimeria spp., and Giardia duodenalis) investigations, we detected BKV using the metagenomic analysis. This result was confirmed using a specific polymerase chain reaction assay that revealed the number of BKV-positive nasal (24.2%) and rectal swabs (31.8%). The prevalence of BKV was higher than that of BCoV. Coinfection with BKV and BCoV was detected in 7.5% of the rectal swabs, highlighting the involvement of another infectious agent in NCD. Using next generation sequencing (NGS) approach, it was possible to obtain the complete sequence of the BKV genome from other two rectal swabs previously analysed by real-time PCR. This is the first report describing the whole genome sequence (WGS) of BKV from Italy. The Italian BKV genomes showed the highest nucleotide sequence identity with BKV KY407744.1, identified in Egypt in 2014. The sequence encoding VP1 best matched that of BKV KY024562, identified in Scotland in 2013. Considering the small number of BKV WGSs available in public databases, further studies are urgently required to assess the whole genome constellation of circulating BKV strains. Furthermore, pathogenicity studies should be conducted by inoculating calves with either only BKV or a combination with other enteric pathogens for understanding the probable role of BKV in NCD.

Inhibition of the SARS-CoV-2 Main Protease by Isoquercitrin γ-Cyclodextrin Inclusion Complex Formulations: A Biochemical and In Silico Study

The main protease (Mpro) of SARS-CoV-2 is a well-established drug target for rational drug design of COVID-19 inhibitors. To address the serious challenge of COVID-19, we have performed biochemical inhibition screens with recombinantly expressed SARS-CoV-2 main protease (Mpro). A fluorescent assay was used to identify the flavonoid isoquercitrin as an Mpro inhibitor. Both isoquercitrin encapsulated in γ-cyclodextrin (inclusion complex formulations) and alone inhibited SARS-CoV-2 Mpro. For isoquercitrin, a Ki value of 32 μM (IC50 = 63 μM) was obtained. Isoquercitrin γ-cyclodextrin inclusion complex formulations additionally inhibited Zika virus NS2B-NS3pro leading to an IC50 value of 98 μM. Formulations containing the other flavonoid compounds diosmetin-7-O-glucoside, hesperetin-7-O-glucoside, and naringenin-7-O-glucoside did not inhibit SARS-CoV-2 Mpro. Steady-state kinetics indicate that the inhibition mechanism of Mpro by isoquercitrin is potentially competitive. Molecular modeling studies carried out with MM/PBSA confirm the likely modes of isoquercitrin binding to both proteases. These modeling results can be used in the development of structural analogs of isoquercitrin with better inhibitory profiles and potential candidates for anti-coronavirus drugs. Since the targeted proteases are essential for viral activity, the delivery isoquercitrin-cyclodextrin inclusion complex formulations could be of great interest for the development of future antiviral drugs to target intracellular virus proteins or other components.

INSIGHT OF PANDEMIC COVID-19: DEVELOPMENTS AND CHALLENGES

This review focuses on the characteristics of coronavirus disease-19 (COVID-19) including virus structure, ecoepidemiology and pathophysiology, signs and symptoms in infected people, and data on virus pathogenicity, severity, and survivability in COVID-19 infected patients. The emphasis is on immunological reactions, diagnosis, prophylactic methods, and the zoonotic significance of COVID-19. The authors feel that the review's contents will be valuable to epidemiologists, virologists, public health officials, diagnosticians, laboratory workers, environmentalists, and socioeconomic experts. It has information on the many types of coronavirus variants, the disease situation in Pakistan and the WHO criteria for COVID-19 prevention is given. Moreover, lessons learned from the COVID-19 pandemic are also outlined.

Impact of Azithromycin and 8-Hydroxychloroquine in 2019 Novel Coronavirus (COVID-19) Pandemic: A Systematic Review

As we know novel coronavirus is an emergent nuisance in this stipulated period. Corona virus is a group of enveloped viruses, with non-segmented, single stranded & positive sense RNA genomes. Human Corona virus is mainly subdivided into four categories such as 229E, NL63, OC43, HKU1. Epidemiologically it has a greater prevalence in the modern era. The features encountered in the clinical course of the disease are multifarious spanning from cough, sneezing, fever, breathlessness. It may take 2-14 days for a person to notice symptoms after infection. Azithromycin and 8 Hydroxychloroquine both plays an instrumental role for management of COVID-19. Azithromycin is a macrolide antibiotic and it binds with a 50s ribosome then inhibits bacterial protein synthesis. On the other hand 8-Hydroxychloroquine was approved by United State in the year of 1955 .Basically it is used as a antimalarial drugs . Briefly, in inflammatory conditions it binds with toll like receptor & blocks them. 8- hydroxychloroquine increases lysosomal pH in antigen presenting cells . In inflammatory conditions it blocks toll like receptors on plasmacytoid dendritic cells. In our review we focused on the role of Azithromycin, and 8-hydroxychloroquine in Covid-19 .Copyright © 2021 International Journal of Pharma and Bio Sciences. All rights reserved.

Tracing the Origin of Genotype II African Swine Fever Virus in China by Genomic Epidemiology Analysis

The pandemic spread of African swine fever (ASF) has caused serious effects on the global pig industry. Virus genome sequencing and genomic epidemiology analysis play an important role in tracking the outbreaks of the disease and tracing the transmission of the virus. Here we obtained the full-length genome sequence of African swine fever virus (ASFV) in the first outbreak of ASF in China on August 3rd, 2018 and compared it with other published genotype II ASFV genomes including 9 genomes collected in China from September 2018 to October 2020. Phylogenetic analysis on genomic sequences revealed that genotype II ASFV has evolved into different genetic clusters with temporal and spatial correlation since being introduced into Europe and then Asia. There was a strong support for the monophyletic grouping of all the ASFV genome sequences from China and other Asian countries, which shared a common ancestor with those from the Central or Eastern Europe. An evolutionary rate of 1.312 × 10−5 nucleotide substitutions per site per year was estimated for genotype II ASFV genomes. Eight single nucleotide variations which located in MGF110-1L, MGF110-7L, MGF360-10L, MGF505-5R, MGF505-9R, K145R, NP419L, and I267L were identified as anchor mutations that defined genetic clusters of genotype II ASFV in Europe and Asia. This study expanded our knowledge of the molecular epidemiology of ASFV and provided valuable information for effective control of the disease.

Characterization and Evaluation of the Pathogenicity of a Natural Gene-Deleted Transmissible Gastroenteritis Virus in China

Porcine transmissible gastroenteritis virus is the major pathogen that causes fatal diarrhea in newborn piglets. In this study, a TGEV strain was isolated from the small intestine of diarrhea piglets in Sichuan Province, China, and designated SC2021. The complete genomic sequence of TGEV SC2021 was 28561 bp, revealing a new natural deletion TGEV strain. Based on phylogenetic analyses, TGEV SC2021 belonged to the Miller cluster and was closely related to CN strains. The newborn piglets orally challenged with TGEV SC2021 showed typical watery diarrhea. In addition, macro and micropathological changes in the lungs and intestines were observed. In conclusion, we isolated a new natural deletion virus strain and confirmed that the virus strain has high pathogenicity in newborn piglets. Moreover, macroscopic and microscopic lesions were observed in the lungs and intestines of all TGEV SC2021-infected piglets. In summary, we isolated a new natural deletion TGEV strain and demonstrated that the natural deletion strain showed high pathogenicity in newborn piglets. These data enrich the diversity of TGEV strains and help us to understand the genetic evolution and molecular pathogenesis of TGEV.

Adapting the GACT-X Aligner to Accelerate Minimap2 in an FPGA Cloud Instance

Featured ApplicationFast long-read assembly to reference in AWS cloud FPGA instances.In genomic analysis, long reads are an emerging type of data processed by assembly algorithms to recover the complete genome sample. They are, on average, one or two orders of magnitude longer than short reads from the previous generation, which provides important advantages in information quality. However, longer sequences bring new challenges to computer processing, undermining the performance of assembly algorithms developed for short reads. This issue is amplified by the exponential growth of genetic data generation and by the slowdown of transistor technology progress, illustrated by Moore's Law. Minimap2 is the current state-of-the-art long-read assembler and takes dozens of CPU hours to assemble a human genome with clinical standard coverage. One of its bottlenecks, the alignment stage, has not been successfully accelerated on FPGAs in the literature. GACT-X is an alignment algorithm developed for FPGA implementation, suitable for any size input sequence. In this work, GACT-X was adapted to work as the aligner of Minimap2, and these are integrated and implemented in an FPGA cloud platform. The measurements for accuracy and speed-up are presented for three different datasets in different combinations of numbers of kernels and threads. The integrated solution's performance limitations due to data transfer are also analyzed and discussed.

Automatic Analysis of Isothermal Amplification via Impedance Time-Constant-Domain Spectroscopy: A SARS-CoV-2 Case Study

The development of sensitive and affordable testing devices for infectious diseases is essential to preserve public health, especially in pandemic scenarios. In this work, we have developed an attractive analytical method to monitor products of genetic amplification, particularly the loop-mediated isothermal amplification reaction (RT-LAMP). The method is based on electrochemical impedance measurements and the distribution of relaxation times model, to provide the so-called time-constant-domain spectroscopy (TCDS). The proposed method is tested for the SARS-CoV-2 genome, since it has been of worldwide interest due to the COVID-19 pandemic. Particularly, once the method is calibrated, its performance is demonstrated using real wastewater samples. Moreover, we propose a simple classification algorithm based on TCDS data to discriminate among positive and negative samples. Results show how a TCDS-based method provides an alternative mechanism for label-free and automated assays, exhibiting robustness and specificity for genetic detection.