Lyso-H2S: A Mycophenolic Acid-Derived Probe for Ultra-Low Toxicity, Intracellular H2S Detection, and Zebrafish Model Validation.

In several biological processes, H2S is known to function as an endogenous gaseous agent. It is very necessary to monitor H2S and relevant physiological processes in vivo. Herein, a new type of fluorophore with a reliable leaving group allows for excited-state intramolecular transfer characteristics (ESIPT), inspired by mycophenolic acid. A morpholine ring was connected at the maleimide position to target the lysosome. Subsequently, the dinitrophenyl group known for a photoinduced electron transfer (PET) effect, was connected to allow for an effective "turn-on" probe Lyso-H2S. Lyso-H2S demonstrated strong selectivity towards H2S, large Stokes shift (111 nm), and an incredibly low detection limit (41.8 nM). The imaging of endogenous and exogenous H2S in living cells (A549 cell line) was successfully achieved because of the specificity and ultra-low toxicity (100 % cell viability at 50 µM concentration of Lyso-H2S.) Additionally, Lyso-H2S was also employed to visualize the activity of H2S in the gallbladder and intestine in a living zebrafish model. This is the first report of a fluorescent probe to track H2S sensing in specific organ systems to our knowledge.

A dual-function fluorescence 'turn-on' probe that allows Zn (II) bioimaging and quantification of water in the organic solvent.

Herein, a Eugenol-derived fluorescence 'turn-on' probe FLHE was synthesized by condensing 2-((3-(trifluoromethyl)phenyl)amino)benzohydrazide with 5-allyl-2-hydroxy-3-methoxybenzaldehyde. FLHE demonstrated very low fluorescence in the studied organic solvents of varying polarities. However, upon titration with Zn2+ in HEPES buffer (pH = 7.4, 50% ACN, v/v), FLHE showed 40-fold higher fluorescence signals indicating the formation of the FLHE-Zn2+ complex. The fluorescence turn-on phenomenon upon FLHE-Zn2+ complex formation results from a chelation-enhanced fluorescence (CHEF) effect. The FLHE-Zn2+ complexation demonstrated a stokes shift of 156 nm (λex = 350 nm, λem = 506 nm) and an about 33-fold increase in the quantum yield (FLHE, Φ = 0.007; FLHE-Zn2+ complex, Φ = 0.23). The binding constant (Ka) determined by the Benesi-Hildebrand plot for interaction between FLHE and Zn2+ was 5.33 × 103 M-1. FLHE demonstrated a LOD of 31.8 nM for detecting Zn2+ in the environmental samples without interference from other cations and anions. FLHE-based paper strip (FLHE-PS) assay was developed to quantify the Zn2+ ions in water and the water content of organic solvent. FLHE-PS allows the detection of Zn2+ in aqueous solutions with a LOD of 63.2 nM and quantifying water in acetonitrile with a LOD of 0.14%. These results indicate that the FLHE has high applicability for detecting Zn2+ in living cells and environmental samples and detecting the presence of water in the organic solvents.

Highly sensitive and rapid detection of hypochlorous acid in aqueous media and its bioimaging in live cells and zebrafish using an ESIPT-driven mycophenolic acid-based fluorescent probe.

Excessive production of potent biological oxidants such as HOCl has been implicated in numerous diseases. Thus, it is crucial to develop highly specific and precise methods to detect HOCl in living systems, preferably with molecules that can show a distinct therapeutic effect. Our study introduces the synthesis and application of a highly sensitive fluorescence "turn-on" probe, Myco-OCl, based on the mycophenolic acid scaffold with exceptional water solubility. The ESIPT-driven mechanism enables Myco-OCl to specifically and rapidly detect (<5 s) HOCl with an impressive Stokes shift of 105 nm (λex = 417 nm, λem = 522 nm) and a sub-nanomolar (97.3 nM) detection limit with the detection range of 0 to 50 µM. The potential of Myco-OCl as an excellent biosensor is evident from its successful application for live cell imaging of exogenous and endogenous HOCl. In addition, Myco-OCl enabled us to detect HOCl in a zebrafish inflammatory animal model. These underscore the great potential of Myco-OCl for detecting HOCl in diverse physiological systems. Our findings thus offer a highly promising tool for detecting HOCl in living organisms.

An abiotic fluorescent probe for the detection and quantification of carcinoembryonic antigen.

The reported methods mainly use biomolecules such as antibodies, enzymes, and aptamers for biomarker detection. However, applying an abiotic fluorescent probe to detect cancer biomarkers such as carcinoembryonic antigen (CEA) has not been reported. In this regard, we conceived an abiotic fluorescent probe BIQ-1 for the rapid yet straightforward detection of CEA. The bioinformatics tools and molecular docking techniques were used to develop the probe BIQ-1 for the selective detection and quantification of CEA in a buffer matrix resembling serum. The probe BIQ-1 exhibited a limit of detection of 0.2 ng/mL for CEA in a simple cuvette-based experiment. The BIQ-1 did no show interference from the possible interfering components such as hemoglobin, intralipid, and human serum albumin (HSA) in concentrations several-fold higher (µg/mL) than CEA.

Synthesis and evaluation of 2-aryl-1H-benzo[d]imidazole derivatives as potential microtubule targeting agents.

Microtubule targeting agents (MTAs) are the potential drug candidates for anticancer drug discovery. Disrupting the microtubule formation or inhibiting the de-polymerization process by a synthetic molecule can lead to an excellent anticancer drug candidate. Here, we present the 2,5-substituted-1H-benzo[d]imidazole derivatives as potential colchicine, nocodazole binding site targeting agents. About 20 benzimidazole derivatives were synthesized with 82.0%-94.0% yield using mild reaction conditions. The synthesized compounds showed moderate to excellent anticancer activity established in three cell lines, including Hela cells, A549 cells, MRC-5 cells. The compounds B15, B16, B19, and B20 are the potential candidates with the IC50 values <15 µM in the three different cell lines. In MTT assay, compounds B15, B16, B19, and B20 showed excellent antiproliferation activity indicated by IC50 values in the range of 5.3 ± 0.21 to 18.1 ± 0.32 µM using HeLa and A549 cell lines. The predicted absorption, distribution, metabolism and excretion (ADME) properties and drug-likeness properties of B15, B16, B19, and B20 indicate that these compounds can be used as lead compounds for further study to develop excellent MTAs.

Development of a Lateral Flow Strip Membrane Assay for Rapid and Sensitive Detection of the SARS-CoV-2.

The infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes the coronavirus disease 2019 (COVID-19) has threatened public health worldwide. The easy human-to-human transmission of this virus has rapidly evolved into a global pandemic. Therefore, to control the community spread of the virus, it is crucial to identify the infected individuals, including asymptomatic people. Hence, a specific and rapid assay is crucial for the early diagnosis and active monitoring of individuals potentially exposed to SARS-CoV-2 for controlling the COVID-19 outbreak. In this study, we have developed the novel lateral flow strip membrane (LFSM) assay that allows the simultaneous detection of RdRp, ORF3a, and N genes using the PCR product obtained by using the single-tube reverse transcription polymerase chain reaction (RT-PCR). The LFSM assay allows detection of SARS-CoV-2 in 30 min at 25 °C after the RT-PCR with the detection limit of 10 copies/test for each gene. The clinical performance of the LFSM assay for the detection of SARS-Cov-2 was evaluated using 162 clinical samples previously detected by using the commercial assay. The percent positive agreement, percent negative agreement, and overall percent agreement of the LFSM assay with the commercial assay were 100% (94.2-100%), 99.0% (94.6-100%), and 99.4% (96.6-100%), respectively. Therefore, the results of the LFSM assay showed significantly high concordance with the commercial assay for the detection of SARS-CoV-2 in clinical specimens. Therefore, we conclude that the developed LFSM assay can be used alone or complementary to the RT-PCR or other methods for the diagnosis and monitoring of the patients to curb community transmission and the pandemic.

Developments in the HCV Screening Technologies Based on the Detection of Antigens and Antibodies.

Hepatitis C virus (HCV) accounts for 15%-20% of cases of acute infection, and chronic HCV infection is developed in about 50%-80% of HCV patients. Unfortunately, due to the lack of proper medical care, difficulty in screening for HCV infection, and lack of awareness resulted in chronic HCV infection in 71 million people on a global scale, and about 399,000 deaths in 2016. It is crucial to recognize that the effective use of antiviral medicines can cure more than 95% of HCV infected people. The Global Health Sector Strategy (GHSS) aim is to reduce the new HCV infections and the HCV associated mortality by 90% and 65%, respectively. Therefore, the methods that are simple, yet powerful enough to detect HCV infections with high sensitivity, specificity, and a shorter window period are crucial to restrain the global burden of HCV healthcare. This article focuses on the technologies used for the detection of HCV in clinical specimens.

Performance of 6 HCV genotyping 9G test for HCV genotyping in clinical samples.

BACKGROUND: A treatment of HCV infection depends on the genotype and sub-genotype. Therefore, accurate HCV genotyping is critical for selecting the appropriate treatment regimen. METHOD: This study included 280 plasma samples to evaluate the performance of 6 HCV Genotyping 9G test. The performance of 6 HCV Genotyping 9G test for accurate detection of HCV 1a, 1b, 2, 3, 4, and 6 genotypes was evaluated by comparing it with LiPA 2.0 assay and sequencing. RESULTS: 6 HCV Genotyping 9G test and LiPA 2.0 assay demonstrated 83.9% (n = 235) agreement. 39/45 samples that showed discrepant results between the two tests were analyzed by sequencing. Sequencing genotyped 39 discrepant samples as 0 (HCV 1a), 24 (HCV 1b), 1 (HCV 6f), 12 (HCV 6i), and 2 (HCV-negative). Results of 6 HCV Genotyping 9G test were very similar to the sequencing as it detected 1, 23, 1, 12, and 2 samples as HCV 1a, 1b, 3 & 6a or 6f, 6i or 6n, and negative, respectively. However, LiPA 2.0 assay showed complete disagreement with sequencing, as it did not detect any of these 39 samples correctly. These results indicate that LiPA 2.0 assay has limitations in identifying HCV genotypes 1b, and 6. The sensitivity, specificity, PPV, and NPV of 6 HCV Genotyping 9G test were 99.5, 98.8, 99.5, and 98.8%, respectively. It is important to note that HCV Genotyping 9G test showed 98.3 and 100% sensitivity for HCV 1b and 6 genotyping, respectively. However, LiPA 2.0 assay demonstrated 57.9 and 71.7% sensitivity for these genotypes. CONCLUSIONS: 6 HCV Genotyping 9G test identifies HCV 1a, 1b, 2, 3, and 6 with good agreement with sequencing. Hence, 6 HCV Genotyping 9G test has a high clinical value because it can provide critical information to physicians and assist them to use the correct drug for efficient hepatitis C treatment.

HCV Detection, Discrimination, and Genotyping Technologies.

According to the World Health Organization (WHO), 71 million people were living with Hepatitis C virus (HCV) infection worldwide in 2015. Each year, about 399,000 HCV-infected people succumb to cirrhosis, hepatocellular carcinoma, and liver failure. Therefore, screening of HCV infection with simple, rapid, but highly sensitive and specific methods can help to curb the global burden on HCV healthcare. Apart from the determination of viral load/viral clearance, the identification of specific HCV genotype is also critical for successful treatment of hepatitis C. This critical review focuses on the technologies used for the detection, discrimination, and genotyping of HCV in clinical samples. This article also focuses on advantages and disadvantages of the reported methods used for HCV detection, quantification, and genotyping.

A glass fibre membrane platform for ultra-sensitive detection of cardiac troponin T.

A glass fibre membrane platform that allows quantification of circulating cTnT with a LoD of 0.87 pg mL-1 is described. The proposed platform uses a glass fibre membrane, DNA-guided detection method, and antibody-conjugated fluorescent beads for the quantification of cTnT in the analytical detection range of 1-120 pg mL-1 at room temperature in 30 min. Glass fibre membranes were chemically modified to immobilize the oligonucleotide probes that catch a biomolecular complex (FB-dAB-cTnT-cAB-DNA) containing complementary oligonucleotides. There were no interferences from human cTnI, cTnC, skTnT, biotin, and hemoglobin (each 1 µg mL-1). The linearity in the serial dilution test of plasma samples indicates that this platform is highly applicable for regular health check-up to assess the risk of AMI and HF.

Ultra-Sensitive NT-proBNP Quantification for Early Detection of Risk Factors Leading to Heart Failure.

Cardiovascular diseases such as acute myocardial infarction and heart failure accounted for the death of 17.5 million people (31% of all global deaths) in 2015. Monitoring the level of circulating N-terminal proBNP (NT-proBNP) is crucial for the detection of people at risk of heart failure. In this article, we describe a novel ultra-sensitive NT-proBNP test (us-NT-proBNP) that allows the quantification of circulating NT-proBNP in 30 min at 25 °C in the linear detection range of 7.0-600 pg/mL. It is a first report on the application of a fluorescence bead labeled detection antibody, DNA-guided detection method, and glass fiber membrane platform for the quantification of NT-proBNP in clinical samples. Limit of blank, limit of detection, and limit of quantification were 2.0 pg/mL, 3.7 pg/mL, and 7 pg/mL, respectively. The coefficient of variation was found to be less than 10% in the entire detection range of 7-600 pg/mL. The test demonstrated specificity for NT-proBNP without interferences from bilirubin, intra-lipid, biotin, and hemoglobin. The serial dilution test for plasma samples containing various NT-proBNP levels showed the linear decrement in concentration with the regression coefficient of 0.980-0.998. These results indicate that us-NT-proBNP test does not suffer from the interference of the plasma components for the measurement of NT-proBNP in clinical samples.

Biomarker detection technologies and future directions.

Biomarkers play a vital role in disease detection and treatment follow-up. It is important to note that diseases in the early stage are typically treated with the greatest probability of success. However, due to various technical difficulties in current technologies for the detection of biomarkers, the potential of biomarkers is not explored completely. Therefore, the developments of technologies, which can enable the accurate detection of prostate cancer at an early stage with simple, experimental protocols are highly inevitable. This critical review evaluates the current methods and technologies used in the detection of biomarkers. The aim of this article is to provide a comprehensive review covering the advantages and disadvantages of the biomarker detection methods. Future directions for the development of technologies to achieve highly selective and sensitive detection of biomarkers for point-of-care applications are also commented on.

Accurate Detection of Rifampicin-Resistant Mycobacterium Tuberculosis Strains.

In 2013 alone, the death rate among the 9.0 million people infected with Mycobacterium tuberculosis (TB) worldwide was around 14%, which is unacceptably high. An empiric treatment of patients infected with TB or drug-resistant Mycobacterium tuberculosis (MDR-TB) strain can also result in the spread of MDR-TB. The diagnostic tools which are rapid, reliable, and have simple experimental protocols can significantly help in decreasing the prevalence rate of MDR-TB strain. We report the evaluation of the 9G technology based 9G DNAChips that allow accurate detection and discrimination of TB and MDR-TB-RIF. One hundred and thirteen known cultured samples were used to evaluate the ability of 9G DNAChip in the detection and discrimination of TB and MDR-TB-RIF strains. Hybridization of immobilized probes with the PCR products of TB and MDR-TB-RIF strains allow their detection and discrimination. The accuracy of 9G DNAChip was determined by comparing its results with sequencing analysis and drug susceptibility testing. Sequencing analysis showed 100% agreement with the results of 9G DNAChip. The 9G DNAChip showed very high sensitivity (95.4%) and specificity (100%).

MTB-DR-RIF 9G membrane: a platform for multiplex SNP detection of multidrug-resistant TB.

The MTB-DR-RIF 9G membrane can detect by detecting multiple mutations in multiple codons. The MTB-DR-RIF 9G membrane possesses clinical applicability in point-of-care settings for the following reasons: (i) 100% similar results with that of the sequencing analysis for clinical samples, (ii) discrimination of the multiple mutations in multiple codons, (iii) a specific/non-specific hybridization ratio higher than 350:1, and (iv) the sensitivity was found to be 1-10 copies/test for detection and discrimination of the wild and mutant TB strains. Graphical abstract Schematic illustration of the effect of controller DNA on the hybridization of the immobilized probes (corresponding to the wild TB strain) with the PCR product of (a) wild TB strain and (b) mutant TB strain.

Biological applications of functionalized calixarenes.

The functionalized calixarene derivatives exhibit remarkable properties towards organic and bioorganic molecules. However, the ability of calixarene derivatives to form stable complexes with biomolecules allows them to be applied for the development of biosensors and in the field of biology, biotechnology, and drug discovery. The applications of the functionalized calixarenes are summarized in this review, and an outlook for the future developments is discussed. A brief survey (of the last 10 years) on their biological application in various fields is also considered (199 references).

HPV genotyping 9G membrane test: a point-of-care diagnostic platform.

The results of HPV detection in 550 cervical samples by cervical cytology were compared with the sequencing analysis and HPV genotyping 9G membrane test. The HPV genotyping 9G membrane test can efficiently identify and discriminate five HR-HPV genotypes. The 100% identical results of HPV genotyping 9G membrane tests with the sequencing results in 550 clinical samples ensure its wide clinical applicability. The simple handling steps and the portable scanning device make the HPV genotyping 9G membrane test applicable in point-of-care settings. Moreover, the HPV genotyping 9G membrane test allows one to obtain final results in 30 min at 25 °C by simply loading the hybridization and washing solution and scanning the membranes without any drying steps or special handling. The clinical sensitivity and specificity of the HPV genotyping 9G membrane test was found to be 100%, which is much higher than cervical cytology.

Immobilization techniques for microarray: challenges and applications.

The highly programmable positioning of molecules (biomolecules, nanoparticles, nanobeads, nanocomposites materials) on surfaces has potential applications in the fields of biosensors, biomolecular electronics, and nanodevices. However, the conventional techniques including self-assembled monolayers fail to position the molecules on the nanometer scale to produce highly organized monolayers on the surface. The present article elaborates different techniques for the immobilization of the biomolecules on the surface to produce microarrays and their diagnostic applications. The advantages and the drawbacks of various methods are compared. This article also sheds light on the applications of the different technologies for the detection and discrimination of viral/bacterial genotypes and the detection of the biomarkers. A brief survey with 115 references covering the last 10 years on the biological applications of microarrays in various fields is also provided.

Development of a DNA-Based Lateral Flow Strip Membrane Assay for Rapid Screening and Genotyping of Six High-Incidence STD Pathogens.

Sexually transmitted diseases (STDs) are a global concern because approximately 1 million new cases emerge daily. Most STDs are curable, but if left untreated, they can cause severe long-term health implications, including infertility and even death. Therefore, a test enabling rapid and accurate screening and genotyping of STD pathogens is highly awaited. Herein, we present the development of the DNA-based 6STD Genotyping 9G Membrane test, a lateral flow strip membrane assay, for the detection and genotyping of six STD pathogens, including Trichomonas vaginalis, Ureaplasma urealyticum, Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma hominis, and Mycoplasma genitalium. Here, we developed a multiplex PCR primer set that allows PCR amplification of genomic materials for these six STD pathogens. We also developed the six ssDNA probes that allow highly efficient detection of the six STD pathogens. The 6STD Genotyping 9G Membrane test lets us obtain the final detection and genotyping results in less than 30 m after PCR at 25 °C. The accuracy of the 6STD Genotyping 9G membrane test in STD genotyping was confirmed by its 100% concordance with the sequencing results of 120 clinical samples. Therefore, the 6STD Genotyping 9G Membrane test emerges as a promising diagnostic tool for precise STD genotyping, facilitating informed decision-making in clinical practice.

The microtubule cytoskeleton: A validated target for the development of 2-Aryl-1H-benzo[d]imidazole derivatives as potential anticancer agents.

In this study, a series of 2-Aryl-1H-benzo[d]imidazole derivatives were developed to target intra- and extracellular microtubule networks. Compounds O-7 and O-10 showed impressive anti-proliferative activity across various tested cell lines, demonstrating selectivity indexes of 151.7 and 61.9, respectively. O-7 achieved an IC50 value of 0.236 ± 0.096 µM, while O-10 showed an IC50 value of 0.622 ± 0.13 µM against A549 cell lines. The induction of early-stage apoptosis in a dose-dependent manner further underscored the potential of O-7 and O-10 as effective anti-proliferative agents. O-7 and O-10 exhibited substantial inhibition of wound closure, with wound closure percentages decreasing from 23% at 0 µM to 0.43% and 2.62% at 20 µM, respectively. Colony formation reduction rates were impressive, with O-7 at 74.2% and O-10 at 81.2%. These results indicate that the O-7 and O-10 can impede cancer cell migration and have a high potential to curtail colony formation. The mode of action investigations for O-7 and O-10 revealed that O-7 could inhibit in vitro tubulin polymerization and disrupt the intracellular microtubule cytoskeleton. This disruption led to cell cycle arrest in the G2/M phase, indicating that O-7 exerts its anticancer activity through microtubule destabilization. However, O-10 shows a different mode of action than O-7 and requires further investigation. Overall, our study showcases the potential of the synthesized benzimidazole derivatives as novel and selective anticancer agents, motivating further exploration of their pharmacological properties and therapeutic applications.

An indole-based near-infrared fluorescent "Turn-On" probe for H2O2: Selective detection and ultrasensitive imaging of zebrafish gallbladder.

Fluorescent probes play essential roles in medical imaging, where the researchers can select one of many molecules to use to help monitor the status of living systems under investigation. To date, a few scaffolds that allow the in vivo detection of H2O2 are available only. Herein, we provide a highly sensitive and selective near-infrared fluorescent probe that detects H2O2 based on the ICT sensing mechanism. We report the first indole-incorporated fluorescent probe Indo-H2O2 that allows H2O2 detection with a LOD of 25.2 nM featuring a boronate group conjugated to an indole scaffold; the boronate cleaves upon reaction with H2O2. A 5-membered malononitrile derivative was incorporated; Indo-H2O2 has near-infrared (NIR) properties and the reaction time is low (∼25 min) compared to other related probes. Indo-H2O2 was successfully employed in both endogenous and exogenous imaging trials of H2O2 in living cells. Indo-H2O2 also allows the real-time monitoring of H2O2in vivo. It preferentially accesses the gallbladder of zebrafish. Our findings support Indo-H2O2 as a highly sensitive fluorescent NIR probe for detecting H2O2, and an idea to incorporate a central indole unit in future fluorescent probe designs.