An Overview on SARS-CoV-2 (COVID-19) and Other Human Coronaviruses and Their Detection Capability via Amplification Assay, Chemical Sensing, Biosensing, Immunosensing, and Clinical Assays

Utilizing Electrochemical-Based Sensing Approaches for the Detection of SARS-CoV-2 in Clinical Samples: A Review

The development of precise and efficient diagnostic tools enables early treatment and proper isolation of infected individuals, hence limiting the spread of coronavirus disease 2019 (COVID-19). The standard diagnostic tests used by healthcare workers to diagnose severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection have some limitations, including longer detection time, the need for qualified individuals, and the use of sophisticated bench-top equipment, which limit their use for rapid SARS-CoV-2 assessment. Advances in sensor technology have renewed the interest in electrochemical biosensors miniaturization, which provide improved diagnostic qualities such as rapid response, simplicity of operation, portability, and readiness for on-site screening of infection. This review gives a condensed overview of the current electrochemical sensing platform strategies for SARS-CoV-2 detection in clinical samples. The fundamentals of fabricating electrochemical biosensors, such as the chosen electrode materials, electrochemical transducing techniques, and sensitive biorecognition molecules, are thoroughly discussed in this paper. Furthermore, we summarised electrochemical biosensors detection strategies and their analytical performance on diverse clinical samples, including saliva, blood, and nasopharyngeal swab. Finally, we address the employment of miniaturized electrochemical biosensors integrated with microfluidic technology in viral electrochemical biosensors, emphasizing its potential for on-site diagnostics applications.

Advancing the Biosynthetic and Chemical Understanding of the Carcinogenic Risk Factor Colibactin and Its Producers

Recent studies have shown that Escherichia coli often carries a biosynthetic gene cluster termed either the pks island or the clb cluster that allows the production of a genotoxic polyketide-nonribosomal peptide hybrid secondary metabolite called colibactin. While the gene cluster is not always expressed, when the strain that resides in the colon produces the genotoxin, it is suspected to become a risk factor for colorectal cancer. Therefore, there is great interest in devising a simple method for the detection of colibactin-producing strains and understanding the detailed mechanism of how colibactin can induce oncogenesis, to develop convenient early screening methods and possible preventive treatments against colorectal cancer. However, the definitive chemical structure of colibactin remained elusive until recently, primarily due to its low yield and instability. In this review, we will briefly trace the recent studies leading to the identification of the structure of the active intact colibactin. Subsequently, we will describe our efforts toward developing simple methods for detecting colibactin producers, where we established methods based on the conventional polymerase chain reaction and loop-mediated isothermal amplification techniques. We also designed an activity-based fluorogenic probe for detecting colibactin-producing strains that could discern colibactin production levels among the E. coli strains screened. Using the probe, we isolated a wild-type high-colibactin-producing strain from a colorectal cancer tissue sample that proved to be valuable in identifying new colibactin metabolites and structurally characterizing them by nuclear magnetic resonance. Those techniques and the chemical insight they furnished should improve the fight against colorectal cancer.

Rapid detection of viruses: Based on silver nanoparticles modified with bromine ions and acetonitrile

Nearly 200 million people have been diagnosed with COVID-19 since the outbreak in 2019, and this disease has claimed more than 5 million lives worldwide. Currently, researchers are focusing on vaccine development and the search for an effective strategy to control the infection source. This work designed a detection platform based on Surface-Enhanced Raman Spectroscopy (SERS) by introducing acetonitrile and calcium ions into the silver nanoparticle reinforced substrate system to realize the rapid detection of novel coronavirus. Acetonitrile may amplify the calcium-induced hot spots of silver nanoparticles and significantly enhanced the stability of silver nanoparticles. It also elicited highly sensitive SERS signals of the virus. This approach allowed us to capture the characteristic SERS signals of SARS-CoV-2, Human Adenovirus 3, and H1N1 influenza virus molecules at a concentration of 100 copies/test (PFU/test) with upstanding reproduction and signal-to-noise ratio. Machine learning recognition technology was employed to qualitatively distinguish the three virus molecules with 1000 groups of spectra of each virus. Acetonitrile is a potent internal marker in regulating the signal intensity of virus molecules in saliva and serum. Thus, we used the SERS peak intensity to quantify the virus content in saliva and serum. The results demonstrated a satisfactory linear relationship between peak intensity and protein concentration. Collectively, this rapid detection method has a broad application prospect in clinical diagnosis of viruses, management of emergent viral infectious diseases, and exploration of the interaction between viruses and host cells.

Genosensors as an alternative diagnostic sensing approaches for specific detection of various certain viruses: a review of common techniques and outcomes

Viral infections are responsible for the deaths of millions of people throughout the world. Since outbreak of highly contagious and mutant viruses such as contemporary sars-cov-2 pandemic, has challenged the conventional diagnostic methods, the entity of a thoroughly sensitive, specific, rapid and inexpensive detecting technique with minimum level of false-positivity or -negativity, is desperately needed more than any time in the past decades. Biosensors as minimized devices could detect viruses in simple formats. So far, various nucleic acid, immune- and protein-based biosensors were designed and tested for recognizing the genome, antigen, or protein level of viruses, respectively; however, nucleic acid-based sensing techniques, which is the foundation of constructing genosensors, are preferred not only because of their ultra-sensitivity and applicability in the early stages of infections but also for their ability to differentiate various strains of the same virus. To date, the review articles related to genosensors are just confined to particular pathogenic diseases; In this regard, the present review covers comprehensive information of the research progress of the electrochemical, optical, and surface plasmon resonance (SPR) genosensors that applied for human viruses' diseases detection and also provides a well description of viruses' clinical importance, the conventional diagnosis approaches of viruses and their disadvantages. This review would address the limitations in the current developments as well as the future challenges involved in the successful construction of sensing approaches with the functionalized nanomaterials and also allow exploring into core-research works regarding this area.

SARS-CoV-2 Infection of Human Ovarian Cells: A Potential Negative Impact on Female Fertility

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may affect female reproductive health. Here, we investigated the potential of SARS-CoV-2 to infect the follicular microenvironment, in particular granulosa (GCs) and cumulus cells (CCs), thus providing evidence for a productive infection. GCs and CCs were recovered from women (n = 25) who underwent in vitro fertilization at the Assisted Reproductive Unit, Siena University Hospital. Follicular ovarian cells were co-cultured with SARS-CoV-2 and then analyzed by qPCR, immunofluorescence (IF), western blot (WB) and transmission electron microscopy (TEM). In addition, cell culture supernatant was used to infect VERO6 cells. We demonstrated the expression of cell host factors ACE2, TRPMSS2, BSG and CTSL, which are pivotal for the virus life cycle. Cultured GCs and CCs incubated with SARS-CoV-2 revealed productive SARS-CoV-2 infection at 24 h, 48 h and 72 h post-adsorption. Indeed, SARS-CoV-2 RNA, spike and nucleocapsid proteins were detected in GCs and CCs, and their cell culture supernatant successfully infected the standard VERO E6 cells. Finally, TEM showed full-size virions attached to the membrane and located inside the cytoplasm. This in vitro study reveals the susceptibility of human ovarian cells to SARS-CoV-2 infection, suggesting a potential detrimental effect of COVID-19 infection on female human fertility.

Recent advances in carbon quantum dots for virus detection, as well as inhibition and treatment of viral infection

In the last decade, carbon quantum dots (CQDs), as a novel class of carbon-based nanomaterials, have received increasing attention due to their distinct properties. CQDs are ultimately small nanoparticles with an average size below 10 nm, possessing high water solubility, alluring photoluminescence, photostability, excellent biocompatibility, low/none toxicity, environmental friendliness, and high sustainability, etc. In history, there are intermittent threats from viruses to humans, animals and plants worldwide, resulting in enormous crises and impacts on our life, environment, economy and society. Some recent studies have unveiled that certain types of CQDs exhibited high and potent antiviral activities against various viruses such as human coronavirus, arterivirus, norovirus and herpesvirus. Moreover, they have been successfully explored and developed for different virus detections including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This article exclusively overviews and discusses the recent progress of designing, synthesizing, modifying/functionalizing and developing CQDs towards effective virus detection as well as the inhibition and treatment of viral infection. Their mechanisms and applications against various pathogenic viruses are addressed. The latest outcomes for combating the coronavirus disease 2019 (COVID-19) utilizing CQDs are also highlighted. It can be envisaged that CQDs could further benefit the development of virus detectors and antiviral agents with added broad-spectrum activity and cost-effective production.

Surface-enhanced Raman scattering-based immunoassay for severe acute respiratory syndrome coronavirus 2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected humans worldwide for over a year now. Although various tests have been developed for the detection of SARS-CoV-2, advanced sensing methods are required for the diagnosis, screening, and surveillance of coronavirus disease 2019 (COVID-19). Here, we report a surface-enhanced Raman scattering (SERS)-based immunoassay involving an antibody pair, SERS-active hollow Au nanoparticles (NPs), and magnetic beads for the detection of SARS-CoV-2. The selected antibody pair against the SARS-CoV-2 antigen, along with the magnetic beads, facilitates the accurate direct detection of the virus. The hollow Au NPs exhibit strong, reproducible SERS signals, allowing sensitive quantitative detection of SARS-CoV-2. This assay had detection limits of 2.56 fg/mL for the SARS-CoV-2 antigen and 3.4 plaque-forming units/mL for the SARS-CoV-2 lysates. Furthermore, it facilitated the identification of SARS-CoV-2 in human nasopharyngeal aspirates and diagnosis of COVID-19 within 30 min using a portable Raman device. Thus, this assay can be potentially used for the diagnosis and prevention of COVID-19.

Capability of novel fluorescence DNA-conjugated CdTe/ZnS quantum dots nanoprobe for COVID-19 sensing

Urgent identification of COVID-19 in infected patients is highly important nowadays. Förster or fluorescence resonance energy transfer (FRET) is a powerful and sensitive method for nanosensing applications, and quantum dots are essential materials in FRET-based nanosensors. The QDs are conjugated to DNA or RNA and used in many applications. Therefore, in the present study, novel fluorescence DNA-conjugated CdTe/ZnS quantum dots nanoprobe designed for detection of Covid-19 after extracting their RNA from saliva of hesitant people. For achieving this purpose, the water-soluble CdTe/ZnS QDs-DNA prepared via replacing the thioglycolic acid (TGA) on the surface of QDs with capture DNA (thiolated DNA) throw a ligand-exchange method. Subsequently, by adding the different concentrations of complementary (target DNA) in a mixture of quencher DNA (BHQ₂-labeled DNA) and the QDs-DNA conjugates at different conditions, sandwiched hybrids were formed. The results showed that the fluorescence intensity was decreased with increasing the concentration of target DNA (as a positive control). The linear equation and regression (Y = 40.302 X  + 1 and R² = 0.98) were obtained by using the Stern-Volmer relationship. The Limit of detection (LOD) was determined 0.000823 µM. The achieved results well confirm the outcomes of the RT-PCR method in real samples.

E.Co.Tech-electrochemical handheld breathalyzer COVID sensing technology

Breathomics is widely emerging as a strategy for non-invasive diagnosis of respiratory inflammation. In this study, we have evaluated the metabolic signals associated with Coronavirus (SARS COV-2), mainly the release of nitric oxide in breath. We have demonstrated the utility of a breath analyzer-based sensor platform for the detection of trace amounts of this target species. The sensor surface is modified with Room Temperature Ionic Liquid (RTIL) that allows faster diffusion of the target gas and can be used for gas sensing application. A low limit of detection (LOD) of 50 parts per billion has been achieved with a 95% confidence interval for detection of nitric oxide.. This inhouse designed sensor is incorporated into a breath analyzer system that displays enhanced sensitivity, specificity, linearity, and reproducibility for NO gas monitoring. The developed sensor platform can detect target concentrations of NO ranging from 50 to 250 ppb, using 1-Ethyl-3-methylimidazolium Tetrafluoroborate ([EMIM]BF4) as RTIL and displays fast response time of 5 s, thereby allowing easy detection of the target gas species. The sensor successfully quantifies the diffusion current and charge modulations arising within the electrical double layer from the RTIL-NO interactions through DC-based chronoamperometry (CA). The subjects tested negative and positive are significantly different (p < 0.01). The prototype can potentially be used for human health monitoring and screening, especially during the pandemic due to its portability, small size, an embedded RTIL sensing element, integrability with a low-power microelectronic device, and an IoT interface.

Insight into prognostics, diagnostics, and management strategies for SARS CoV-2

The foremost challenge in countering infectious diseases is the shortage of effective therapeutics. The emergence of coronavirus disease (COVID-19) outbreak has posed a great menace to the public health system globally, prompting unprecedented endeavors to contain the virus. Many countries have organized research programs for therapeutics and management development. However, the longstanding process has forced authorities to implement widespread infrastructures for detailed prognostic and diagnostics study of severe acute respiratory syndrome (SARS CoV-2). This review discussed nearly all the globally developed diagnostic methodologies reported for SARS CoV-2 detection. We have highlighted in detail the approaches for evaluating COVID-19 biomarkers along with the most employed nucleic acid- and protein-based detection methodologies and the causes of their severe downfall and rejection. As the variable variants of SARS CoV-2 came into the picture, we captured the breadth of newly integrated digital sensing prototypes comprised of plasmonic and field-effect transistor-based sensors along with commercially available food and drug administration (FDA) approved detection kits. However, more efforts are required to exploit the available resources to manufacture cheap and robust diagnostic methodologies. Likewise, the visualization and characterization tools along with the current challenges associated with waste-water surveillance, food security, contact tracing, and their role during this intense period of the pandemic have also been discussed. We expect that the integrated data will be supportive and aid in the evaluation of sensing technologies not only in current but also future pandemics.

Characterization of Rheum ribes with ZnO nanoparticle and its antidiabetic, antibacterial, DNA damage prevention and lipid peroxidation prevention activity of in vitro

This study aims to investigate the antidiabetic, antimicrobial, DNA damage, and lipid peroxidation prevention activity of ZnO NPs/Rr formed as a result of the interaction of Rheum ribes (R.ribes) plant with ZnO. The ZnO NPs/Rr obtained as a result of the reaction were confirmed using high-reliability characterization methods. According to the data obtained as a result of the study, it is seen that the activity of ZnO NPs/Rr to prevent lipid peroxidation is quite strong. Lipid peroxidation inhibition activity of ZnO NPs/Rr at the highest concentration of 250 μg/ml was calculated as % 89.1028. It was observed that ZnO NPs/Rr prevented DNA damage by % 92.1240 at the highest concentration of 100 μg/ml. It was determined that the antidiabetic effect of ZnO NPs/Rr formed by ZnO of R. ribes plant, which is used as a medicinal plant as an antidiabetic, was significant. It appears to have a strong antidiabetic property compared to the positive control acarbose. In our current study, it was observed that ZnO NPs/Rr formed zones ranging from 8 ± 3.0 to 21 ± 4.5 against Gram-positive and Gram-negative microorganisms. It has been determined that ZnO nanoparticles have an antibacterial effect.

Recent advances in the highly sensitive determination of zearalenone residues in water and environmental resources with electrochemical biosensors

Zearalenone (ZEN), a significant class of mycotoxin which is considered as a xenoestrogen, permits, similar to natural estrogens, it's binding to the receptors of estrogen resulting in various reproductive diseases especially, hormonal misbalance. ZEN has toxic effects on human and animal health as a result of its teratogenicity, carcinogenicity, mutagenicity, nephrotoxicity, genotoxicity, and immunotoxicity. To ensure water and environmental resources safety, precise, rapid, sensitive, and reliable analytical and conventional methods can be progressed for the determination of toxins such as ZEN. Different selective nanomaterial-based compounds are used in conjunction with different analytical detection approaches to achieve this goal. The current review demonstrates the state-of-the-art advances of nanomaterial-based electrochemical sensing assays including various sensing, apta-sensing and, immunosensing studies to the highly sensitive determination of various ZEN families. At first, a concise study of the occurrence, structure, toxicity, legislations, and distribution of ZEN in monitoring has been performed. Then, different conventional and clinical techniques and procedures to sensitive and selective sensing techniques have been reviewed and the efficient comparison of them has been thoroughly discussed. This study has also summarized the salient features and the requirements for applying various sensing and biosensing platforms and diverse immobilization techniques in ZEN detection. Finally, we have defined the performance of several electrochemical sensors applying diverse recognition elements couples with nanomaterials fabricated using various recognition elements coupled with nanomaterials (metal NPs, metal oxide nanoparticles (NPs), graphene, and CNT) the issues limiting development, and the forthcoming tasks in successful construction with the applied nanomaterials.

Arum italicum mediated silver nanoparticles: Synthesis and investigation of some biochemical parameters

The science world advancing day by day contributes to living systems in many areas with the development of nanotechnology. Besides being easily obtained from plants, the advantages it brings increase the importance of nanotechnology. Environmentally friendly, economical, and compatible with plants are just a few of the advantages it brings. Silver metal is one of the most preferred active ingredients in nanoparticle synthesis. Arum italicum is used in the treatment of various diseases in the health sector due to the structures it contains. In our study, nanoparticle synthesis was made by using Ag metal with Arum italicum plant. Then, the antimicrobial, DNA damage prevention and DPPH radical quenching activity of Ag NPs/Ai nanoparticles were investigated. The interaction of the plant with Ag, analysis by X-ray diffraction (XRD), UV visible spectrophotometer (UV-vis), scanning electron microscope and energy dispersive X-ray (SEM-EDX), Fourier-converted infrared spectroscopy (FT-IR) methods has been done. It has been observed that Ag NPs/Ai clusters formed by Arum italicum with Ag have an antibacterial effect against Bacillus subtilis, Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli pathogens. However, an antifungal effect hasn't been observed against Candida albicans fungus. Pseudomonas aeruginosa bacteria exerted a stronger effect than an antibiotic. It is seen that Ag NPs/Ai has a protective and anti-damage effect against DNA damage. The antioxidant effect of Ag NPs/Ai is remarkable when DPPH radical quenching activity is compared to positive control BHA and BHT.

State of the art: Lateral flow assays toward the point-of-care foodborne pathogenic bacteria detection in food samples

Diverse chemicals and some physical phenomena recently introduced in nanotechnology have enabled scientists to develop useful devices in the field of food sciences. Concerning such developments, detecting foodborne pathogenic bacteria is now an important issue. These kinds of bacteria species have demonstrated severe health effects after consuming foods and high mortality related to acute cases. The most leading path of intoxication and infection has been through food matrices. Hence, quick recognition of foodborne bacteria agents at low concentrations has been required in current diagnostics. Lateral flow assays (LFAs) are one of the urgent and prevalently applied quick recognition methods that have been settled for recognizing diverse types of analytes. Thus, the present review has stressed on latest developments in LFAs-based platforms to detect various foodborne pathogenic bacteria such as Salmonella, Listeria, Escherichia coli, Brucella, Shigella, Staphylococcus aureus, Clostridium botulinum, and Vibrio cholera. Proper prominence has been given on exactly how the labels, detection elements, or procedures have affected recent developments in the evaluation of diverse bacteria using LFAs. Additionally, the modifications in assays specificity and sensitivity consistent with applied food processing techniques have been discussed. Finally, a conclusion has been drawn for highlighting the main challenges confronted through this method and offered a view and insight of thoughts for its further development in the future.

Electrochemical sensors for the detection of SARS-CoV-2 virus

Coronavirus (COVID-19), a deadly pandemic has spread worldwide and created many global health issues. Though methods of its detection are being continuously developed for the early detection and monitoring of COVID-19, still there is need for more novel methods. The presently used methods include rapid antigen tests, serological surveys, reverse transcription-polymerase chain reaction (RT-PCR), artificial intelligence-based techniques, and assays based on sensors/biosensors. Of all these, RT-PCR test has high sensitivity and specificity though it requires more time for testing and need for skilled technicians. Recently, electrochemical sensors have been developed for rapid monitoring and detection of SARS-CoV-2 from the patient's biological fluid samples. This review covers the recently developed electrochemical sensors that are focused on the detection of viral nucleic acid, immunoglobulin, antigen, and the entire viral particles. In addition, we also compare and assess their detection limits, sensitivities and specificities for the identification and monitoring of COVID-19. Furthermore, this review will address the best practices for the development of electrochemical sensors such as electrode fouling, limit of detection/limit of quantification determination and verification.

Computational Method-Based Optimization of Carbon Nanotube Thin-Film Immunosensor for Rapid Detection of SARS-CoV-2 Virus

The recent global spread of COVID-19 stresses the importance of developing diagnostic testing that is rapid and does not require specialized laboratories. In this regard, nanomaterial thin-film-based immunosensors fabricated via solution processing are promising, potentially due to their mass manufacturability, on-site detection, and high sensitivity that enable direct detection of virus without the need for molecular amplification. However, thus far, thin-film-based biosensors have been fabricated without properly analyzing how the thin-film properties are correlated with the biosensor performance, limiting the understanding of property-performance relationships and the optimization process. Herein, the correlations between various thin-film properties and the sensitivity of carbon nanotube thin-film-based immunosensors are systematically analyzed, through which optimal sensitivity is attained. Sensitivities toward SARS-CoV-2 nucleocapsid protein in buffer solution and in the lysed virus are 0.024 [fg/mL]-1 and 0.048 [copies/mL]-1, respectively, which are sufficient for diagnosing patients in the early stages of COVID-19. The technique, therefore, can potentially elucidate complex relationships between properties and performance of biosensors, thereby enabling systematic optimization to further advance the applicability of biosensors for accurate and rapid point-of-care (POC) diagnosis.

A PCR-free genosensing platform for detection of Shigella dysenteriae in human plasma samples by porous and honeycomb-like biochar decorated with ultrathin flower-like MoS2 nanosheets incorporated with Au nanoparticles

Shigella dysenteriae, a gram-negative bacterium, which results in the most infectious of bacterial shigellosis and dysenteries. In this study, an innovative gene detection platform based on label-free DNA sequences was developed to detect Shigella dysenteriae in human plasma samples. The porous and honeycomb-like structure of biochar (BC) was first synthesized through a pyrolysis process. Then, the produced biochar was effectively decorated with flower-like MoS₂ nanosheets (MoS₂/BC). The resulting nanocomposite was incorporated with Au nanoparticles (AuNPs) by applying chronoamperometry technique, and then the subsequent product including MoS₂ nanosheets, biochar and AuNPs were immobilized on the Au electrode surface and used for modifier agent in electrochemical bio-assays. Structural and morphological study of the synthesized compounds were investigated using various characterization methods such as FE-SEM, TEM, EDS, FTIR, and XRD. Various electrochemical techniques including cyclic voltammetry (CV) and Differential pulse anodic stripping voltammetry (DPASV) have been used to investigate the applicability of the fabricated genosensing bio-assay. Under optimal conditions, LOD and LOQ were calculated 9.14 fM and 0.018 pM respectively. In addition, a linear range from 0.01 to 100 pM was obtained for single stranded-target DNA (ss-tDNA), with R² of 0.9992. The recoveries ranged from 98.0 to 101.3%. The fabricated bio-detection assay demonstrated high selectivity for 1, 2, and 3 base mismatch sequences. In addition, a negative control of the gene detection platform which was performed to study selectivity was provided by ss-tDNA from Haemophilusinfluenzae, and Salmonella typhimurium. Moreover, it is important to mention that the organized bioassay is simply reusable and reproducible with the RSD% (relative standard deviation) ˂ 5 to next detection assays.

PEDOT-AuNPs-based impedimetric immunosensor for the detection of SARS-CoV-2 antibodies

Electrochemical sensors and biosensors are useful techniques for fast, inexpensive, sensitive, and easy detection of innumerous specimen. In face of COVID-19 pandemic, it became evident the necessity of a rapid and accurate diagnostic test, so the impedimetric immunosensor approach can be a good alternative to replace the conventional tests due to the specific antibody-antigen binding interaction and the fast response in comparison to traditional methods. In this work, a modified electrode with electrosynthesized PEDOT and gold nanoparticles followed by the immobilization of truncated nucleoprotein (N aa160-406aa) was used for a fast and reliable detection of antibodies against COVID-19 in human serum sample. The method consists in analyzing the charge-transfer resistance (R_CT) variation before and after the modified electrode comes into contact with the positive and negative serum sample for COVID-19, using [Fe(CN)₆]^3-/4- as a probe. The results show a linear and selective response for serum samples diluted in a range of 2.5 × 10³ to 20 × 10³. Also, the electrode material was fully characterized by Raman spectroscopy, transmission electron microscopy and scanning electron microscopy coupled with EDS, indicating that the gold nanoparticles were well distributed around the polymer matrix and the presence of the biological sample was confirmed by EDS analysis. EIS measurements allowed to differentiate the negative and positive samples by the difference in the R_CT magnitude, proving that the material developed here has potential properties to be applied in impedimetric immunosensors for the detection of SARS-CoV-2 antibodies in about 30 min.

Aptamers-Diagnostic and Therapeutic Solution in SARS-CoV-2

The SARS-CoV-2 virus is currently the most serious challenge to global public health. Its emergence has severely disrupted the functioning of health services and the economic and social situation worldwide. Therefore, new diagnostic and therapeutic tools are urgently needed to allow for the early detection of the SARS-CoV-2 virus and appropriate treatment, which is crucial for the effective control of the COVID-19 disease. The ideal solution seems to be the use of aptamers—short fragments of nucleic acids, DNA or RNA—that can bind selected proteins with high specificity and affinity. They can be used in methods that base the reading of the test result on fluorescence phenomena, chemiluminescence, and electrochemical changes. Exploiting the properties of aptamers will enable the introduction of rapid, sensitive, specific, and low-cost tests for the routine diagnosis of SARS-CoV-2. Aptamers are excellent candidates for the development of point-of-care diagnostic devices and are potential therapeutic tools for the treatment of COVID-19. They can effectively block coronavirus activity in multiple fields by binding viral proteins and acting as carriers of therapeutic substances. In this review, we present recent developments in the design of various types of aptasensors to detect and treat the SARS-CoV-2 infection.

Novel enzymatic graphene oxide based biosensor for the detection of glutathione in biological body fluids

In this work, we report a novel enzymatic biosensor based on glutathione peroxidase (GSH-Px), graphene oxide (GO) and nafion for the electrochemical sensing of glutathione (GSH) in body fluids. GSH-Px was immobilized covalently via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) onto modified glassy carbon electrode (GCE) decorated with GO and nafion and successfully used for sensing of GSH in the presence of H₂O₂ as catalyst with Michaelis-Menten constant about 0.131 mmol/L. The active surface are of GCE improve from 0.183 cm² to 0.225 cm² after modification with GO. The introduced biosensor (GSH-Px/GO/nafion/GCE) was used for monitoring of GSH over the range 0.003-370.0 μM, with a detection limit of 1.5 nM using differential pulse voltammetric (DPV) method. The GSH-Px/GO/nafion/GCE was successfully applied to the determination of GSH in real samples.

Bimetallic Fe/Mn MOFs/MβCD/AuNPs stabilized on MWCNTs for developing a label-free DNA-based genosensing bio-assay applied in the determination of Salmonella typhimurium in milk samples

Monitoring of pathogenic bacteria plays a vital role in precluding foodborne disease outbreaks. In this research work, a genosensor based on innovative label-free DNA was developed for the detection of Salmonella. typhimurium (S. typhimurium) in the milk samples. To realize this objective, bimetallic Fe/Mn MOF is synthesized and mixed with methyl-β-cyclodextrin (MβCD) and AuNPs which are then stabilized on multi-walled carbon nanotubes (MWCNTs), and the obtained nanocomposite is immobilized on the Au electrode surface. Different characterization methods such as FE-SEM, TEM, EDS, FTIR, and XRD were used for investigating the particle size and morphological features. Electrochemical and impedimetric techniques were used for exploring the applicability of the fabricated genosensor. Under optimal circumstances, LOD and LOQ have acquired at 0.07 pM and 0.21 pM. Moreover, an extensive linear range of 1 pM-1 μM was resulted for ss-tDNA (single-stranded target DNA), R² obtained 0.9991. The recoveries were obtained 95.6-104%. Great selectivity against one, two, and three-base mismatched sequences was also shown for fabricated biosensing assay. Furthermore, negative genosensing assay control for investigating selectivity was provided by the ss-tDNAs of Haemophilusinfluenzae and Shigella dysenteriae bacteria. Well-fabricated genosensing bio-assay represents better performance, great specificity, high sensitivity, increased active sites, and finally results in an increase in the electron transfer rate. It is to be noted that the organized genosensing bio-assay is capable of being re-used and re-generated in a straightforward manner to estimate the hybridization process.

Nanobioengineering: A promising approach for early detection of COVID-19

Unique pneumonia due to an unknown source emerged in December 2019 in the city of Wuhan, China. Consequently, the World Health Organization (WHO) declared this condition as a new coronavirus disease-19 also known as COVID-19 on February 11, 2020, which on March 13, 2020 was declared as a pandemic. The virus that causes COVID-19 was found to have a similar genome (80% similarity) with the previously known acute respiratory syndrome also known as SARS-CoV. The novel virus was later named Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 falls in the family of Coronaviridae which is further divided into Nidovirales and another subfamily called Orthocoronavirinae. The four generations of the coronaviruses belongs to the Orthocoronavirinae family that consists of alpha, beta, gamma and delta coronavirus which are denoted as α-CoV, β-CoV, γ-CoV, δ-CoV respectively. The α-CoV and β-CoVs are mainly known to infect mammals whereas γ-CoV and δ-CoV are generally found in birds. The β-CoVs also comprise of SARS-CoV and also include another virus that was found in the Middle East called the Middle East respiratory syndrome virus (MERS-CoV) and the cause of current pandemic SARS-CoV-2. These viruses initially cause the development of pneumonia in the patients and further development of a severe case of acute respiratory distress syndrome (ARDS) and other related symptoms that can be fatal leading to death.

Silicon Nitride-BP-Based Surface Plasmon Resonance Highly Sensitive Biosensor for Virus SARS-CoV-2 Detection

In this study, we propose a surface plasmon resonance (SPR)-based biosensor using silicon nitride (Si₃N₄), black phosphorous (BP), and thiol-tethered DNA as a ligand for fast detection of the SARS-CoV-2 virus. In the proposed biosensor, we have deposited silver (Ag), Si₃N₄, and BP on the base of the BK-7 prism and investigated the performance parameters on the probe in different combinations of the mentioned materials. Herein, three (Ag, Si₃N₄, and BP) different configurations are introduced and compared for the detection of SARS-CoV-2. Furthermore, with the help of the transfer matrix method (TMM), all the three configurations have been analyzed. Notably, the combination of Ag, Si₃N₄, and BP shows better sensitivity (154°/RIU) when compared with other configurations for the detection of SARS-CoV-2. This work may facilitate a new sensing device to detect SARS-CoV-2, based on the hybrid materials.

Emerging importance of nanotechnology-based approaches to control the COVID-19 pandemic; focus on nanomedicine iterance in diagnosis and treatment of COVID-19 patients

The ongoing outbreak of the newly emerged coronavirus disease 2019, which has tremendously concerned global health safety, is the result of infection with severe acute respiratory syndrome of coronavirus 2 with high morbidity and mortality. Because of the coronavirus has no specific treatment, so it is necessary to early detection and produce antiviral agents and efficacious vaccines in order to prevent the contagion of coronavirus. Due to the unique properties of nanomaterials, nanotechnology appears to be a highly relevant discipline in this global emergency, providing expansive chemical functionalization to develop advanced biomedical tools. Fascinatingly, nanomedicine as a hopeful approach for the treatment and diagnosis of diseases, could efficiently help success the fight among coronavirus and host cells. In this review, we will critically discuss how nanomedicine can play an indispensable role in creating useful treatments and diagnostics for coronavirus.

Tetrahedron-Based Constitutional Dynamic Network for COVID-19 or Other Coronaviruses Diagnostics and Its Logic Gate Applications

Considering the large-scale outbreak of the coronavirus, it is essential to develop a versatile sensing system for different coronaviruses diagnostics, such as COVID-19, severe acute respiratory syndrome-related coronavirus (SARS-CoV), and bat SARS-like coronavirus (Bat-SL-CoVZC45). In this work, a tetrahedron-based constitutional dynamic network was built as the sensing platform for coronavirus detection. Four different DNA probes were used to construct the tetrahedron structure. DNAzyme and the fluorophore modified substrate strand were used to generate different fluorescence signals, which can be used to distinguish different coronaviruses. The coronavirus biosensor shows a high sensitivity for COVID-19, Bat-SL-CoVZC45, and SARS-CoV detection, with detection limits of 2.5, 3.1, and 2.9 fM, respectively. Also, the platform is robust, and the possible interference from clinical samples was negligible. Using different coronaviruses as inputs, we have fabricated several concatenated logic gates, such as "AND-OR", "INHIBIT-AND", "AND-AND-AND", and "AND-INHIBIT". Importantly, our logic system can also be used to identify SARS-CoV-2 Delta and Lambda variants in the logic operations. Due to the unique advantages of high sensitivity and selectivity, multiple logic biocomputing capabilities, and multireadout mode, this flexible sensing system provides a versatile sensing strategy for intelligent diagnostics of different coronaviruses with low false-negative rates.

Human Body Performance with COVID-19 Affectation According to Virus Specification Based on Biosensor Techniques

Life was once normal before the first announcement of COVID-19's first case in Wuhan, China, and what was slowly spreading became an overnight worldwide pandemic. Ever since the virus spread at the end of 2019, it has been morphing and rapidly adapting to human nature changes which cause difficult conundrums in the efforts of fighting it. Thus, researchers were steered to investigate the virus in order to contain the outbreak considering its novelty and there being no known cure. In contribution to that, this paper extensively reviewed, compared, and analyzed two main points; SARS-CoV-2 virus transmission in humans and detection methods of COVID-19 in the human body. SARS-CoV-2 human exchange transmission methods reviewed four modes of transmission which are Respiratory Transmission, Fecal-Oral Transmission, Ocular transmission, and Vertical Transmission. The latter point particularly sheds light on the latest discoveries and advancements in the aim of COVID-19 diagnosis and detection of SARS-CoV-2 virus associated with this disease in the human body. The methods in this review paper were classified into two categories which are RNA-based detection including RT-PCR, LAMP, CRISPR, and NGS and secondly, biosensors detection including, electrochemical biosensors, electronic biosensors, piezoelectric biosensors, and optical biosensors.

Multiplexed Profiling of Extracellular Vesicles for Biomarker Development

Extracellular vesicles (EVs) are cell-derived membranous particles that play a crucial role in molecular trafficking, intercellular transport and the egress of unwanted proteins. They have been implicated in many diseases including cancer and neurodegeneration. EVs are detected in all bodily fluids, and their protein and nucleic acid content offers a means of assessing the status of the cells from which they originated. As such, they provide opportunities in biomarker discovery for diagnosis, prognosis or the stratification of diseases as well as an objective monitoring of therapies. The simultaneous assaying of multiple EV-derived markers will be required for an impactful practical application, and multiplexing platforms have evolved with the potential to achieve this. Herein, we provide a comprehensive overview of the currently available multiplexing platforms for EV analysis, with a primary focus on miniaturized and integrated devices that offer potential step changes in analytical power, throughput and consistency.

Lateral flow assays (LFA) as an alternative medical diagnosis method for detection of virus species: The intertwine of nanotechnology with sensing strategies

Viruses are responsible for multiple infections in humans that impose huge health burdens on individuals and populations worldwide. Therefore, numerous diagnostic methods and strategies have been developed for prevention, management, and decreasing the burden of viral diseases, each having its advantages and limitations. Viral infections are commonly detected using serological and nucleic acid-based methods. However, these conventional and clinical approaches have some limitations that can be resolved by implementing other detector devices. Therefore, the search for sensitive, selective, portable, and costless approaches as efficient alternative clinical methods for point of care testing (POCT) analysis has gained much attention in recent years. POCT is one of the ultimate goals in virus detection, and thus, the tests need to be rapid, specific, sensitive, accessible, and user-friendly. In this review, after a brief overview of viruses and their characteristics, the conventional viral detection methods, the clinical approaches, and their advantages and shortcomings are firstly explained. Then, LFA systems working principles, benefits, classification are discussed. Furthermore, the studies regarding designing and employing LFAs in diagnosing different types of viruses, especially SARS-CoV-2 as a main concern worldwide and innovations in the LFAs' approaches and designs, are comprehensively discussed here. Furthermore, several strategies addressed in some studies for overcoming LFA limitations like low sensitivity are reviewed. Numerous techniques are adopted to increase sensitivity and perform quantitative detection. Employing several visualization methods, using different labeling reporters, integrating LFAs with other detection methods to benefit from both LFA and the integrated detection device advantages, and designing unique membranes to increase reagent reactivity, are some of the approaches that are highlighted.

Ultra-sensitive and fast optical detection of the spike protein of the SARS-CoV-2 using AgNPs/SiNWs nanohybrid based sensors

Severe acute respiratory syndrome SARS-CoV-2 virus led to notable challenges amongst researchers in view of development of new and fast detecting techniques. In this regard, surface-enhanced Raman spectroscopy (SERS) technique, providing a fingerprint characteristic for each material, would be an interesting approach. The current study encompasses the fabrication of a SERS sensor to study the SARS-CoV-2 S1 (RBD) spike protein of the SARS-CoV-2 virus family. The SERS sensor consists of a silicon nanowires (SiNWs) substrate decorated with plasmonic silver nanoparticles (AgNPs). Both SiNWs fabrication and AgNPs decoration were achieved by a relatively simple wet chemical processing method. The study deliberately projects the factors that influence the growth of silicon nanowires, uniform decoration of AgNPs onto the SiNWs matrix along with detection of Rhodamine-6G (R6G) to optimize the best conditions for enhanced sensing of the spike protein. Increasing the time period of etching process resulted in enhanced SiNWs' length from 0.55 to 7.34 µm. Furthermore, the variation of the immersion time in the decoration process of AgNPs onto SiNWs ensued the optimum time period for the enhancement in the sensitivity of detection. Tremendous increase in sensitivity of R6G detection was perceived on SiNWs etched for 2 min (length=0.90 µm), followed by 30s of immersion time for their optimal decoration by AgNPs. These SiNWs/AgNPs SERS-based sensors were able to detect the spike protein at a concentration down to 9.3 × 10^-12 M. Strong and dominant peaks at 1280, 1404, 1495, 1541 and 1609 cm^-1 were spotted at a fraction of a minute. Moreover, direct, ultra-fast, facile, and affordable optoelectronic SiNWs/AgNPs sensors tuned to function as a biosensor for detecting the spike protein even at a trace level (pico molar concentration). The current findings hold great promise for the utilization of SERS as an innovative approach in the diagnosis domain of infections at very early stages.

Development of dipodal fluorescence sensor of iron for real samples based on pyrene modified anthracene

A novel pyrene modified anthracene dipodal sensor was prepared by a simple synthetic method for the sensitive determination of iron ions in real samples. The chemical characterization analyses including nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry were carried out to characterize the target fluorescent sensor. Photophysical and electrochemical behaviors of the sensor were studied by the absorption, excitation-emission matrix analysis, steady-state fluorescence, three-dimensional fluorescence, and cyclic and square wave voltammetry, respectively. The fluorescent sensor properties were evaluated via Ultraviolet-visible and fluorescence spectroscopies. According to obtained results, the fluorescence signal of the sensor was selectively quenched with interaction with Fe³⁺ ions. The spectrofluorimetric determination of iron, in real water and medicine samples were successfully carried out under optimized experimental conditions. A detection limit and linear working range were calculated as 0.265 μM and 0.275-55.000 μM, respectively which demonstrated the ability of the simple and sensitive sensor for slight amounts of iron. The obtained detection limit for iron determination with the presented novel fluorescent sensor was less than nearly 20 times the tolerance limit (5.40 µM) in drinking water that was determined by the United States Environmental Protection Agency. The accuracy of the newly developed method was evaluated by Inductively coupled plasma optical emission spectroscopy and spike/recovery test which demonstrated that the developed fluorescent sensor has high accuracy for fast, easy and accessible determination of iron at 95% confidence level.

Surrogate test performance for SARS-CoV-2 neutralizing antibodies (nAbs) for convalescent plasma (CCP): How useful could they be?

Background

COVID‐19 high‐titer CCP selection is a concern, because neutralizing antibody (nAb) testing requires sophisticated labs and methods. Surrogate tests are an alternative for measuring nAb levels in plasma bags, including those that are pathogen‐reduced.

Study design/methods

We studied a panel consisting of 191 samples from convalescent donors tested by nAb (CPE‐VNT), obtained from 180 CCP donations (collection: March 20–January 21) and 11 negative controls, with a total of 80 and 111 serum and plasma samples (71 amotosalen/UV treated), with nAb titers ranging from negative to 10,240. Samples were blindly tested for several surrogates: one anti‐RBD, two anti‐spike, and four anti‐nucleocapsid tests, either isolated or combined to improve their positive predictive values as predictors of the presence of high‐titer nAbs, defined as those with titers ≥160.

Results

Except for combined and anti‐IgA/M tests, all isolated surrogate tests showed excellent performance for nAb detection: sensitivity (98.3%–100%), specificity (85.7%–100%), PPV (98.9%–100%), NPV (81.3%–100%), and AUC (0.93–0.96), with a variable decrease in sensitivity and considerably lower specificity when using FDA authorization and concomitant nAb titers ≥160. All surrogates had AUCs that were statistically different from CPE‐VNT if nAb≥160, including when using combined, orthogonal approaches.

Conclusions

Surrogate tests (isolated or in combination) have an indirect good performance in detecting the presence of nAb, with lower sensitivity and specificity when high nAb titer samples are used, possibly accepting a considerable number of donors whose nAb titers are actually low, which should be evaluated by each laboratory responsible for CCP collection.

Two-dimensional biomaterials: material science, biological effect and biomedical engineering applications

To date, nanotechnology has increasingly been identified as a promising and efficient means to address a number of challenges associated with public health. In the past decade, two-dimensional (2D) biomaterials, as a unique nanoplatform with planar topology, have attracted explosive interest in various fields such as biomedicine due to their unique morphology, physicochemical properties and biological effect. Motivated by the progress of graphene in biomedicine, dozens of types of ultrathin 2D biomaterials have found versatile bio-applications, including biosensing, biomedical imaging, delivery of therapeutic agents, cancer theranostics, tissue engineering, as well as others. The effective utilization of 2D biomaterials stems from the in-depth knowledge of structure-property-bioactivity-biosafety-application-performance relationships. A comprehensive summary of 2D biomaterials for biomedicine is still lacking. In this comprehensive review, we aim to concentrate on the state-of-the-art 2D biomaterials with a particular focus on their versatile biomedical applications. In particular, we discuss the design, fabrication and functionalization of 2D biomaterials used for diverse biomedical applications based on the up-to-date progress. Furthermore, the interactions between 2D biomaterials and biological systems on the spatial-temporal scale are highlighted, which will deepen the understanding of the underlying action mechanism of 2D biomaterials aiding their design with improved functionalities. Finally, taking the bench-to-bedside as a focus, we conclude this review by proposing the current crucial issues/challenges and presenting the future development directions to advance the clinical translation of these emerging 2D biomaterials.

Development of an ultrasensitive fluorescent immunochromatographic assay based on multilayer quantum dot nanobead for simultaneous detection of SARS-CoV-2 antigen and influenza A virus

Rapid and accurate diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus (FluA) antigens in the early stages of virus infection is the key to control the epidemic spread. Here, we developed a two-channel fluorescent immunochromatographic assay (ICA) for ultrasensitive and simultaneous qualification of the two viruses in biological samples. A high-performance quantum dot nanobead (QB) was fabricated by adsorption of multilayers of dense quantum dots (QDs) onto the SiO2 surface and used as the highly luminescent label of the ICA system to ensure the high-sensitivity and stability of the assay. The combination of monodispersed SiO2 core (∼180 nm) and numerous carboxylated QDs formed a hierarchical shell, which ensured that the QBs possessed excellent stability, superior fluorescence signal, and convenient surface functionalization. The developed ICA biosensor achieved simultaneous detection of SARS-CoV-2 and FluA in one test within 15 min, with detection limits reaching 5 pg/mL for SARS-CoV-2 antigen and 50 pfu/mL for FluA H1N1. Moreover, our method showed high accuracy and specificity in throat swab samples with two orders of magnitude improvement in sensitivity compared with traditional AuNP-based ICA method. Hence, the proposed method is a promising and convenient tool for detection of respiratory viruses.

Simple workflow to repurpose SARS-CoV-2 swab/serum samples for the isolation of cost-effective antibody/antigens for proteotyping applications and diagnosis

Supply shortage for the development and production of preventive, therapeutic, and diagnosis tools during the COVID-19 pandemic is an important issue affecting the wealthy and poor nations alike. Antibodies and antigens are especially needed for the production of immunological-based testing tools such as point-of-care tests. Here, we propose a simple and quick magnetic nanoparticle (MNP)–based separation/isolation approach for the repurposing of infected human samples to produce specific antibodies and antigen cocktails. Initially, an antibody cocktail was purified from serums via precipitation and immunoaffinity chromatography. Purified antibodies were conjugated onto MNPs and used as an affinity matrix to separate antigens. The characterization process was performed by ELISA, SDS-PAGE, electrochemistry, isothermal titration calorimetry, and LC-Q-TOF-MS/MS analyses. The MNP-separated peptides can be used for mass spectrometry–based as well as paper-based lateral flow assay diagnostic. The exploitation of the current workflow for the development of efficient diagnostic tools, specific treatments, and fundamental research can significantly impact the present or eventual pandemic. This workflow can be considered as a two birds, one stone–like strategy.

First-Principles Simulation of Dielectric Function in Biomolecules

The dielectric spectra of complex biomolecules reflect the molecular heterogeneity of the proteins and are particularly important for the calculations of electrostatic (Coulomb) and electrodynamic (van der Waals) interactions in protein physics. The dielectric response of the proteins can be decomposed into different components depending on the size, structure, composition, locality, and environment of the protein in general. We present a new robust simulation method anchored in rigorous ab initio quantum mechanical calculations of explicit atomistic models, without any indeterminate parameters to compute and gain insight into the dielectric spectra of small proteins under different conditions. We implement this methodology to a polypeptide RGD-4C (1FUV) in different environments, and the SD1 domain in the spike protein of SARS-COV-2. Two peaks at 5.2-5.7 eV and 14.4-15.2 eV in the dielectric absorption spectra are observed for 1FUV and SD1 in vacuum as well as in their solvated and salted models.

A comprehensive review of COVID-19 biology, diagnostics, therapeutics, and disease impacting the central nervous system

The ongoing COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a highly transmissible disease. SARS-CoV-2 is estimated to have infected over 153 million people and to have caused over 3.2 million global deaths since its emergence in December 2019. SARS-CoV-2 is the seventh coronavirus known to infect humans, and like other coronaviruses, SARS-CoV-2 infection is characterized by a variety of symptoms including general flu-like symptoms such as a fever, sore throat, fatigue, and shortness of breath. Severe cases often display signs of pneumonia, lymphopenia, acute kidney injury, cardiac injury, cytokine storms, lung damage, acute respiratory distress syndrome (ARDS), multiple organ failure, sepsis, and death. There is evidence that around 30% of COVID-19 cases have central nervous system (CNS) or peripheral nervous system (PNS) symptoms along with or in the absence of the previously mentioned symptoms. In cases of CNS/PNS impairments, patients display dizziness, ataxia, seizure, nerve pain, and loss of taste and/or smell. This review highlights the neurological implications of SARS-CoV-2 and provides a comprehensive summary of the research done on SARS-CoV-2 pathology, diagnosis, therapeutics, and vaccines up to May 5.

Nanoscale Metal-Organic Frameworks: Recent developments in synthesis, modifications and bioimaging applications

Porous Metal-Organic Frameworks (MOFs) have emerged as eye-catching materials in recent years. They are widely used in numerous fields of chemistry thanks to their desirable properties. MOFs have a key role in the development of bioimaging platforms that are hopefully expected to effectually pave the way for accurate and selective detection and diagnosis of abnormalities. Recently, many types of MOFs have been employed for detection of RNA, DNA, enzyme activity and small-biomolecules, as well as for magnetic resonance imaging (MRI) and computed tomography (CT), which are valuable methods for clinical analysis. The optimal performance of the MOF in the bio-imaging field depends on the core structure, synthesis method and modifications processes. In this review, we have attempted to present crucial parameters for designing and achieving an efficient MOF as bioimaging platforms, and provide a roadmap for researchers in this field. Moreover, the influence of modifications/fractionalizations on MOFs performance has been thoroughly discussed and challenging problems have been extensively addressed. Consideration is mainly focused on the principal concepts and applications that have been achieved to modify and synthesize advanced MOFs for future applications.

Dye-Loaded Polymersome-Based Lateral Flow Assay: Rational Design of a COVID-19 Testing Platform by Repurposing SARS-CoV-2 Antibody Cocktail and Antigens Obtained from Positive Human Samples

The global pandemic of COVID-19 continues to be an important threat, especially with the fast transmission rate observed after the discovery of novel mutations. In this perspective, prompt diagnosis requires massive economical and human resources to mitigate the disease. The current study proposes a rational design of a colorimetric lateral flow immunoassay (LFA) based on the repurposing of human samples to produce COVID-19-specific antigens and antibodies in combination with a novel dye-loaded polymersome for naked-eye detection. A group of 121 human samples (61 serums and 60 nasal swabs) were obtained and analyzed by RT-PCR and ELISA. Pooled samples were used to purify antibodies using affinity chromatography, while antigens were purified via magnetic nanoparticles-based affinity. The purified proteins were confirmed for their specificity to COVID-19 via commercial LFA, ELISA, and electrochemical tests in addition to sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. Polymersomes were prepared using methoxy polyethylene glycol-b-polycaprolactone (mPEG-b-PCL) diblock copolymers and loaded with a Coomassie Blue dye. The polymersomes were then functionalized with the purified antibodies and applied for the preparation of two types of LFA (antigen test and antibody test). Overall, the proposed diagnostic tests demonstrated 93 and 92.2% sensitivity for antigen and antibody tests, respectively. The repeatability (92-94%) and reproducibility (96-98%) of the tests highlight the potential of the proposed LFA. The LFA test was also analyzed for stability, and after 4 weeks, 91-97% correct diagnosis was observed. The current LFA platform is a valuable assay that has great economical and analytical potential for widespread applications.

Recent Advances in Nanomaterials Development for Nanomedicine and Cancer

Cancer is considered one of the leading causes of death, with a growing number of cases worldwide. However, the early diagnosis and efficient therapy of cancer have remained a critical challenge. The emergence of nanomedicine has opened up a promising window to address the drawbacks of cancer detection and treatment. A wide range of engineered nanomaterials and nanoplatforms with different shapes, sizes, and composition has been developed for various biomedical applications. Nanomaterials have been increasingly used in various applications in bioimaging, diagnosis, and therapy of cancers. Recently, numerous multifunctional and smart nanoparticles with the ability of simultaneous diagnosis and targeted cancer therapy have been reported. The multidisciplinary attempts led to the development of several exciting clinically approved nanotherapeutics. The nanobased materials and devices have also been used extensively to develop point-of-care and highly sensitive methods of cancer detection. In this review article, the most significant achievements and latest advances in the nanomaterials development for cancer nanomedicine are critically discussed. In addition, the future perspectives of this field are evaluated.

Aptamer-based lateral flow assay on-site biosensors

The lateral flow assay (LFA) is a widely used paper-based on-site biosensor that can detect target analytes and obtain test results in several minutes. Generally, antibodies are utilized as the biorecognition molecules in the LFA. However, antibodies selected using an in vivo process not only may risk killing the animal hosts and causing errors between different batches but also their range is restricted by the refrigerated conditions used to store them. To avoid these limitations, aptamers screened by an in vitro process have been studied as biorecognition molecules in LFAs. Based on the sandwich or competitive format, the aptamer-based LFA can accomplish on-site detection of target analytes. Since aptamers have a distinctive ability to undergo conformational changes, the adsorption-desorption format has also been exploited to detect target analytes in aptamer-based LFAs. This paper reviews developments in aptamer-based LFAs in the last three years for the detection of target analytes. Three formats of aptamer-based LFAs, i.e., sandwich, competitive, and adsorption-desorption, are described in detail. Based on these formats, signal amplification strategies and multiplexed detection are discussed in order to provide an overview of aptamer-based LFAs for on-site detection of target analytes. In addition, the potential commercialization and future perspectives of aptamer-based LFAs for rapid detection of SARS-CoV-2 are given to support the COVID-19 pandemic.

Science's Response to CoVID-19

CoVID-19 is a multi-symptomatic disease which has made a global impact due to its ability to spread rapidly, and its relatively high mortality rate. Beyond the heroic efforts to develop vaccines, which we do not discuss herein, the response of scientists and clinicians to this complex problem has reflected the need to detect CoVID-19 rapidly, to diagnose patients likely to show adverse symptoms, and to treat severe and critical CoVID-19. Here we aim to encapsulate these varied and sometimes conflicting approaches and the resulting data in terms of chemistry and biology. In the process we highlight emerging concepts, and potential future applications that may arise out of this immense effort.

Lithium bioleaching: An emerging approach for the recovery of Li from spent lithium ion batteries

The rapidly growing demand for lithium has resulted in a sharp increase in its price. This is due to the ubiquitous use of lithium-ion batteries (LIBs) in large-scale energy and transportation sectors as well as portable devices. Recycling of the LIBs for being the supply of critical metals hence becomes environmentally and economically viable. The presently used approaches for the recovery of spent LIBs like pyrometallurgical process can effectively recover nickel, cobalt, and copper, while lithium is usually lost in slag. Bioleaching process as an alternative method of extraction and recovery of valuable metals from the primary and secondary resources has been attracting a large pool of attraction. This method can provide higher recovery yield even for low concentration of metals which makes it viable among conventional methods. The bioleaching process can work with lower operating cost and consumed water and energy along with a simple condition, which produces less hazardous by-products ultimately. Here, we comprehensively review the biological and chemical mechanisms of the bioleaching process with a conclusive discussion to help how to extend the use of bioleaching for lithium extraction and recovery from the spent LIBs with a focus on recovery yields improvement. We elaborate on the three main types of the reported bioleaching with considering effective parameters including temperature, initial pH, pulp density, aeration, and medium and cell nutrients to sustain microorganism activity. Finally, practical challenges and future opportunities of lithium are discussed to inspire future research trends and pilot studies to realize the full potential of lithium recovery using sustainable bioleaching processes to extend a clean energy future.

COVID-19 Biomarkers and Advanced Sensing Technologies for Point-of-Care (POC) Diagnosis

COVID-19, also known as SARS-CoV-2 is a novel, respiratory virus currently plaguing humanity. Genetically, at its core, it is a single-strand positive-sense RNA virus. It is a beta-type Coronavirus and is distinct in its structure and binding mechanism compared to other types of coronaviruses. Testing for the virus remains a challenge due to the small market available for at-home detection. Currently, there are three main types of tests for biomarker detection: viral, antigen and antibody. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) remains the gold standard for viral testing. However, the lack of quantitative detection and turnaround time for results are drawbacks. This manuscript focuses on recent advances in COVID-19 detection that have lower limits of detection and faster response times than RT-PCR testing. The advancements in sensing platforms have amplified the detection levels and provided real-time results for SARS-CoV-2 spike protein detection with limits as low as 1 fg/mL in the Graphene Field Effect Transistor (FET) sensor. Additionally, using multiple biomarkers, detection levels can achieve a specificity and sensitivity level comparable to that of PCR testing. Proper biomarker selection coupled with nano sensing detection platforms are key in the widespread use of Point of Care (POC) diagnosis in COVID-19 detection.