Innovations in dengue virus detection: An overview of conventional and electrochemical biosensor approaches.

Globally, people are in great threat due to the highly spreading of viral infectious diseases. Every year like 100-300 million cases of infections are found, and among them, above 80% are not recognized and irrelevant. Dengue virus (DENV) is an arbovirus infection that currently infects people most frequently. DENV encompasses four viral serotypes, and they each express comparable sign. From a mild febrile sickness to a potentially fatal dengue hemorrhagic fever, dengue can induce a variety of symptoms. Presently, the globe is being challenged by the untimely identification of dengue infection. Therefore, this review summarizes advances in the detection of dengue from conventional methods (nucleic acid-based, polymerase chain reaction-based, and serological approaches) to novel biosensors. This work illustrates an extensive study of the current designs and fabrication approaches involved in the formation of electrochemical biosensors for untimely identifications of dengue. Additionally, in electrochemical sensing of DENV, we skimmed through significances of biorecognition molecules like lectins, nucleic acid, and antibodies. The introduction of emerging techniques such as the CRISPR/Cas' system and their integration with biosensing platforms has also been summarized. Furthermore, the review revealed the importance of electrochemical approach compared with traditional diagnostic methods.

Graphene Oxide Nanoparticles Modified Paper Electrode as a Biosensing Platform for Detection of the htrA Gene of O. tsutsugamushi.

The unique structural and electrochemical properties of graphene oxide (GO) make it an ideal material for the fabrication of biosensing devices. Therefore, in the present study, graphene oxide nanoparticles modified paper electrodes were used as a low-cost matrix for the development of an amperometric DNA sensor. The graphene oxide was synthesized using the modified hummers method and drop cast on a screen-printed paper electrode (SPPE) to enhance its electrochemical properties. Further, the GO/SPPE electrode was modified with a 5'NH2 labeled ssDNA probe specific to the htrA gene of Orientia tsutsugamushi using carbodiimide cross-linking chemistry. The synthesized GO was characterized using UV-Vis, FTIR, and XRD. The layer-by-layer modification of the paper electrode was monitored via FE-SEM, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). The sensor response after hybridization with single-stranded genomic DNA (ssGDNA) of O. tsutsugamushi was recorded using differential pulse voltammetry (DPV). Methylene blue (1 mM in PBS buffer, pH 7.2) was used as a hybridization indicator and [Fe(CN)6]-3/-4 (2.5 mM in PBS buffer, pH 7.2) as a redox probe during electrochemical measurements. The developed DNA sensor shows excellent sensitivity (1228.4 µA/cm2/ng) and LOD (20 pg/µL) for detection of O. tsutsugamushi GDNA using differential pulse voltammetry (DPV).

Leptospira interrogans Outer Membrane Protein-Based Nanohybrid Sensor for the Diagnosis of Leptospirosis.

Leptospirosis is an underestimated tropical disease caused by the pathogenic Leptospira species and responsible for several serious health problems. Here, we aimed to develop an ultrasensitive DNA biosensor for the rapid and on-site detection of the Loa22 gene of Leptospira interrogans using a gold nanoparticle-carbon nanofiber composite (AuN/CNF)-based screen-printed electrode. Cyclic voltammetry and electrochemical impedance were performed for electrochemical analysis. The sensitivity of the sensor was 5431.74 µA/cm2/ng with a LOD (detection limit) of 0.0077 ng/µL using cyclic voltammetry. The developed DNA biosensor was found highly specific to the Loa22 gene of L. interrogans, with a storage stability at 4 °C for 180 days and a 6% loss of the initial response. This DNA-based sensor only takes 30 min for rapid detection of the pathogen, with a higher specificity and sensitivity. The promising results obtained suggest the application of the developed sensor as a point of care device for the diagnosis of leptospirosis.

Applications of Nanotechnology in Sensor-Based Detection of Foodborne Pathogens.

The intake of microbial-contaminated food poses severe health issues due to the outbreaks of stern food-borne diseases. Therefore, there is a need for precise detection and identification of pathogenic microbes and toxins in food to prevent these concerns. Thus, understanding the concept of biosensing has enabled researchers to develop nanobiosensors with different nanomaterials and composites to improve the sensitivity as well as the specificity of pathogen detection. The application of nanomaterials has enabled researchers to use advanced technologies in biosensors for the transfer of signals to enhance their efficiency and sensitivity. Nanomaterials like carbon nanotubes, magnetic and gold, dendrimers, graphene nanomaterials and quantum dots are predominantly used for developing biosensors with improved specificity and sensitivity of detection due to their exclusive chemical, magnetic, mechanical, optical and physical properties. All nanoparticles and new composites used in biosensors need to be classified and categorized for their enhanced performance, quick detection, and unobtrusive and effective use in foodborne analysis. Hence, this review intends to summarize the different sensing methods used in foodborne pathogen detection, their design, working principle and advances in sensing systems.

Recent advances in biosensors for diagnosis of celiac disease: A review.

Celiac disease (CD) is an intestinal issue activated by the inappropriate immune reaction towards gluten protein of wheat, rye, barley, oats, and autoantigen, tissue transglutaminase. Regardless of the accessibility of immunochemical conventions for research facility analysis of CD, there is as yet a need of speedier, less expensive, and simpler devices for diagnosing CD. This review concentrates on progresses in biosensors for diagnosing CD in perspective of the scaled down hardware, multianalyte discovery and low sample volume necessity. Various recently developed biosensors in this field are presented.

A Nano-Au/C-MWCNT based label free amperometric immunosensor for the detection of capsicum chlorosis virus in bell pepper.

Accurate and on time diagnosis of plant viruses is an essential prerequisite for efficient control in field conditions. A number of diagnostic methods have been reported with the required level of sensitivity. Here, we propose a label free immunosensor for efficient and sensitive detection of capsicum chlorosis virus (CaCV) in bell pepper. Antigen was immobilized over the surface of gold nanoparticle/multi-walled carbon nanotube (Nano-Au/C-MWCNT) screen printed electrodes using 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC)/N-hydroxysuccinimide (NHS) cross linking chemistry followed by interaction with groundnut bud necrosis virus (GBNV)/CaCV specific polyclonal antibody. The electrochemical response was measured by cyclic voltammetry (CV), differential pulse voltammetry (DPV) using the redox indicator. Electrode surface characterization was done by performing scanning electron microscopy (SEM). Electrochemical studies showed positive results at different antigenic dilutions ranging from 10-2 - 8x10-5. The sensitivity of the immunosensor developed has been compared with direct antigen coated enzyme-linked immunosorbent assay (DAC-ELISA) and the results showed that the immunosensor developed was 800-1000 times more sensitive, when compared to DAC-ELISA for CaCV detection. The immunosensor we have developed is economical and sensitive and could be used for immediate determination of the presence of virus in extracts from bell pepper leaves.

Gene Specific Impedimetric Bacterial DNA Sensor for Rheumatic Heart Disease.

An impedimetric mga gene specific DNA sensor was developed by immobilization of single stranded DNA probe onto the screen printed modified gold-dendrimer nanohybrid composite electrode for early and rapid detection of S. pyogenes in human throat swab samples causing rheumatic heart disease. Electrochemical impedance response was measured after hybridization with bacterial single stranded genomic DNA (ssG-DNA) with probe. The sensor was found highly specific to S. pyogenes and can detect as low as 0.01 ng ssDNA in 6 µL sample only in 30 min. The nanohybrid sensor was also tested with non-specific pathogens and characterized by FTIR. An early detection of the pathogen S. pyogenes in human can save damage of mitral and aortic heart valves (rheumatic heart disease) by proper medical care.

Nano-Au/cMWCNT Modified speB Gene Specific Amperometric Sensor for Rapidly Detecting Streptococcus pyogenes causing Rheumatic Heart Disease.

A specific 5' NH2 labeled DNA probe of speB gene was immobilized onto the gold nanoparticles/carboxylated multi walled carbon nanotubes (Nano-Au/cMWCNT) screen printed electrode using EDC/NHS cross linking chemistry. This was followed by hybridization with 0.5-50 ng/6 µl of single stranded genomic DNA Streptococcus pyogenes infected patient throat swab samples. Electrochemical amperometric assay was deciphered by using cyclic voltammetry (CV) with methylene blue a redox indicator. The sensor had a sensitivity of 104.7 µA cm-2 ng-1 using CV with a R2 of 0.907 and 0.01 ng/6 µl as the limit of detection (LOD). The modified electrode surface morphology was characterized using scanning electron microscopy. The stability of the electrode was seen at 4 °C for 180 days having 6% loss in the initial current. The sensor is speB gene specific and can detect the pathogen within 30 min.

Gold-mercaptopropionic acid-polyethylenimine composite based DNA sensor for early detection of rheumatic heart disease.

The first gold-mercaptopropionic acid-polyethylenimine composite based electrochemical DNA biosensor was fabricated for the early detection of Streptococcus pyogenes infection in humans causing rheumatic heart disease (heart valve damage). No biosensor is available for the detection of rheumatic heart disease (RHD). Therefore, the mga gene based sensor was developed by the covalent immobilization of a 5'-carboxyl modified single stranded DNA probe onto the gold composite electrode. The immobilized probe was hybridized with the genomic DNA (G-DNA) of S. pyogenes from throat swabs and the electrochemical response was measured by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance (EI). Covalent immobilization of the probe onto the gold composite and its hybridization with G-DNA was characterized by FTIR and SEM. The sensitivity of the sensor was 110.25 µA cm(-2) ng(-1) with DPV and the lower limit of detection was 10 pg per 6 µL. The sensor was validated with patient throat swab samples and results were compared with available methods. The sensor is highly specific to S. pyogenes and can prevent damage to heart valves by the early detection of the infection in only 30 min.

Vaccine development: Current trends and technologies.

Despite the effectiveness of vaccination in reducing or eradicating diseases caused by pathogens, there remain certain diseases and emerging infections for which developing effective vaccines is inherently challenging. Additionally, developing vaccines for individuals with compromised immune systems or underlying medical conditions presents significant difficulties. As well as traditional vaccine different methods such as inactivated or live attenuated vaccines, viral vector vaccines, and subunit vaccines, emerging non-viral vaccine technologies, including viral-like particle and nanoparticle vaccines, DNA/RNA vaccines, and rational vaccine design, offer new strategies to address the existing challenges in vaccine development. These advancements have also greatly enhanced our understanding of vaccine immunology, which will guide future vaccine development for a broad range of diseases, including rapidly emerging infectious diseases like COVID-19 and diseases that have historically proven resistant to vaccination. This review provides a comprehensive assessment of emerging non-viral vaccine production methods and their application in addressing the fundamental and current challenges in vaccine development.

Exosomal miRNAs as Next-generation Therapy Vehicles in Breast Cancer.

The second most pervasive cancer affecting the survival of women across the world is breast cancer. One of the biggest challenges in breast cancer treatment is the chemoresistance of cancer cells to various medications after some time. Therefore, highly specific blood-based biomarkers are required for early breast cancer diagnosis to overcome chemoresistance and improve patient survival. These days, exosomal miRNAs have attracted much attention as early diagnostic blood-based biomarkers because of their high stability, secretion from malignant tumor cells, and excellent specificity for different breast cancer subtypes. In addition, exosomal miRNAs regulate cell proliferation, invasion, metastasis, and apoptosis by binding to the 3'UTR of their target genes and limiting their production. This review focuses on the functions of exosomal miRNAs in tumorigenesis via targeting multiple signaling pathways as well as chemosensitivity and resistance mechanisms. In addition, the growing pieces of evidence discussed in this review suggest that circulating exosomal miRNAs could be utilized as potential next-generation therapeutic target vehicles in the treatment of breast cancer.

Aberrant protein glycosylation: Implications on diagnosis and Immunotherapy.

Glycosylation-mediated post-translational modification is critical for regulating many fundamental processes like cell division, differentiation, immune response, and cell-to-cell interaction. Alterations in the N-linked or O-linked glycosylation pattern of regulatory proteins like transcription factors or cellular receptors lead to many diseases, including cancer. These alterations give rise to micro- and macro-heterogeneity in tumor cells. Here, we review the role of O- and N-linked glycosylation and its regulatory function in autoimmunity and aberrant glycosylation in cancer. The change in cellular glycome could result from a change in the expression of glycosidases or glycosyltransferases like N-acetyl-glucosaminyl transferase V, FUT8, ST6Gal-I, DPAGT1, etc., impact the glycosylation of target proteins leading to transformation. Moreover, the mutations in glycogenes affect glycosylation patterns on immune cells leading to other related manifestations like pro- or anti-inflammatory effects. In recent years, understanding the glycome to cancer indicates that it can be utilized for both diagnosis/prognosis as well as immunotherapy. Studies involving mass spectrometry of proteome, site- and structure-specific glycoproteomics, or transcriptomics/genomics of patient samples and cancer models revealed the importance of glycosylation homeostasis in cancer biology. The development of emerging technologies, such as the lectin microarray, has facilitated research on the structure and function of glycans and glycosylation. Newly developed devices allow for high-throughput, high-speed, and precise research on aberrant glycosylation. This paper also discusses emerging technologies and clinical applications of glycosylation.

Current Update on Biomarkers for Detection of Cancer: Comprehensive Analysis.

Early and effective diagnosis of cancer is decisive for its proper management. In this context biomarker-based cancer diagnosis is budding as one of the promising ways for early detection, disease progression monitoring, and effective cancer therapy. Integration of Biosensing devices with different metallic/nonmetallic nanoparticles offers amplification and multiplexing capabilities for simultaneous detection of cancer biomarkers (CB's). This study provides a comprehensive analysis of the most recent designs and fabrication methodologies designed for developing electrochemical biosensors (EB) for early detection of cancers. The role of biomarkers in cancer therapeutics is also discussed.

Development of paper-based DNA sensor for detection of O. tsutsugamushi using sustainable GQDs@AuNPs nanocomposite.

The graphene quantum dots (GQDs) was synthesized using potato starch and water by hydrothermal method and further used for reduction of tetracholoroauric acid to form graphene quantum dots-gold (GQDs@AuNPs) nanocomposite. The GQDs/GQDs@AuNPs were analyzed using FTIR, UV-Vis, Flourometry and HR-TEM. The synthesized GQDs@AuNPs were further used for fabrication of cost-effective screen-printed paper electrode (SPPE) based DNA sensor for the detection of O. tsutsugamushi using htrA gene specific 5'NH2 linked DNA probe. Modification of SPPE using GQDs@AuNPs nanocomposite and ssDNA probe was monitored using EIS, FTIR, FE-SEM and AFM. The sensor detection limit (LOD) was assessed as 0.002 ng/µl from the standard calibration curve with the correlation coefficient, R2 = 0.993. The sensitivity of the DNA sensor was calculated as 7700 µA/cm2/ng for ssGDNA of O. tsutsugamushi using cyclic voltammetry. The sensor validation was done using scrub typhus patient's blood DNA samples. The sensor showed good storage stability at 4 °C for six months with just a loss of 12% of the initial current values. The SPPE/DNA sensor developed is very specific, sensitive, stable and detects O. tsutsugamushi in less time.

The Colloquy between Microbiota and the Immune System in Colon Cancer: Repercussions on the Cancer Therapy.

Colorectal cancer is the second leading cause of cancer deaths worldwide and has engrossed researchers' attention toward its detection and prevention at early stages. Primarily associated with genetic and environmental risk factors, the disease has also shown its emergence due to dysbiosis in microbiota. The microbiota not only plays a role in modulating the metabolisms of metastatic tissue but also has a keen role in cancer therapy. The immune cells are responsible for secreting various chemokines and cytokines, and activating pattern recognition receptors by different microbes can lead to the trail by which these cells regulate cancer. Furthermore, mixed immune reactions involving NK cells, tumor-associated macrophages, and lymphocytes have shown their connection with the microbial counterpart of the disease. The microbes like Bacteroides fragilis, Fusobacterium nucleatum, and Enterococcus faecalis and their metabolites have engendered inflammatory reactions in the tumor microenvironment. Hence the interplay between immune cells and various microbes is utilized to study the changing metastasis stage. Targeting either immune cells or microbiota could not serve as a key to tackling this deadly disorder. However, harnessing their complementation towards the disease can be a powerful weapon for developing therapy and diagnostic/prognostic markers. In this review, we have discussed various immune reactions and microbiome interplay in CRC, intending to evaluate the effectiveness of chemotherapy and immunotherapy and their parallel relationship.

Recent Advances and a Roadmap to Aptamer-Based Sensors for Bloodstream Infections.

The present review is intended to describe bloodstream infections (BSIs), the major pathogens responsible for BSIs, conventional tests and their limitations, commercially available methods used, and the aptamer and nanomaterials-based approaches developed so far for the detection of BSIs. The advantages associated with aptamers and the aptamer-based sensors, the comparison between the aptamers and the antibodies, and the various types of aptasensors developed so far for the detection of bloodstream infections have been described in detail in the present review. Also, the future outlook and roadmap toward aptamer-based sensors and the challenges associated with the aptamer development have also been concluded in this review.

Nanohybrid electrochemical enzyme sensor for xanthine determination in fish samples.

An amperometric biosensor for xanthine was designed, based on covalent immobilization of xanthine oxidase (XO) of Bacillus pumilus RL-2d onto a screen-printed multi-walled carbon nanotubes gold nanoparticle-based electrodes (Nano-Au/c-MWCNT). The carboxyl groups at the electrode surface were activated by the use of 1-Ethyl-3-(3-dimethylaminopropyl carbodiimide) (EDC) and N-hydroxysuccinimide (NHS). The working electrode was then coated with 6 µL of xanthine oxidase (0.273 U/mg protein). The cyclic voltammetry (CV) study was done for the characterization of the sensor using [K3Fe(CN)6] as an artificial electron donor. The sensitivity (S) and the limit of detection (LOD) of the biosensor were 2388.88 µA/cm2/nM (2.388 µA/cm2/µM) and 1.14 nM, respectively. The developed biosensor was used for determination of fish meat freshness.

PlcA-based nanofabricated electrochemical DNA biosensor for the detection of Listeria monocytogenes in raw milk samples.

The electrochemical DNA biosensor has been developed for the detection of Listeria monocytogenes in raw milk samples. The electrochemical studies of the developed biosensor was recorded by cyclic voltammetry (CV) and electrochemical impedance (EI) using methylene blue (MB) and potassium ferricyanide K3Fe(CN)- 6 as redox indicators. The selectivity of the developed biosensor was demonstrated using complementary and mismatch oligonucleotide sequences. The sensitivity (S) of the developed sensor was recorded as 3461 (µA/cm2)/ng and limit of detection (LOD) was found to be 82 fg/6 µl with the regression coefficient (R 2) 0.941 using CV. The sensor was characterized by field emission scanning electron microscopy (FE-SEM). The electrode was found to be stable for six months, with only 10% loss in the initial CV current.

Recent advances in the diagnosis of leptospirosis.

Leptospirosis can be found in virtually all tropical and temperate areas of the world and is presumed to be the widely spread zoonotic infection in the world. Because of the variety of clinical symptoms seen in the symptomatic cases, leptospirosis at its onset is often misdiagnosed as aseptic meningitis, influenza, hepatic disease or fever (pyrexia) of unknown origin. The disease has been widely spread, ranging from subclinical infection to a severe syndrome of multiorgan infection with high mortality. It is an occupational hazard for people who work outdoors or with animals, such as rice and sugar-cane field workers, farmers, sewer workers, veterinarians, dairy workers, and military personnel. Various diagnostic methods have been developed for the diagnosis of leptospirosis that includes direct examination; serology and molecular based techniques, but have various shortcomings, so there is a need to develop an effective surveillance system to monitor the trends of disease to control this life-threatening zoonosis. Now a day's biosensor based technology becomes an excellent platform in the field of diagnostics due to their better sensitivity and specificity. So different types of biosensors such as enzyme-based, tissue-based, immunosensor, DNA biosensors, thermal and piezoelectric biosensors have been discussed here to highlight their indispensable applications in different fields. In this review, we will examine the current utilization of functionalized detection methods with other synthetic mixes for the development of biosensor prompting to the location of particular analytes with low discovery cut-off and quick reaction.

Diagnosis of scrub typhus: recent advancements and challenges.

Scrub typhus is a mite-borne, acute febrile illness caused by the bacterium Orientia tsutsugamushi. It is a re-emerging infectious disease of the tsutsugamushi triangle. Scrub typhus is transmitted through bites of contaminated chiggers (larval stage). Diagnosis of scrub typhus is challenging as its symptoms mimic with other acute febrile illnesses. Several methods are effectual for diagnosis of scrub typhus that includes enzyme-linked immunosorbent assay (ELISA), immunofluorescence assay (IFA), immunochromatographic test (ICT), Weil-Felix, polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP). Weil-Felix test was initially used for the diagnosis of scrub typhus in underdeveloped countries but not preferred due to a lack of both specificity and sensitivity. Other immuno-based methods like IFA and ELISA are most outrank for detection of scrub typhus due to their higher sensitivity and specificity, but not vigorous to lay bare the infection at early stages and need the convalescent sampling for verification of positive samples. On another deed, PCR based methods becoming acceptable over era due to its dexterity of early-stage diagnosis with higher specificity and sensitivity but lack its applicability in circumstances of scrub typhus due to the variegated genetic makeup of Orientia tsutsugamushi among its serotypes. The present review focused on various detection methods along with their advantages and disadvantages used in the diagnosis of scrub typhus. A comparison between available methods of diagnosis with challenges in the detection of scrub typhus is also summarized.