Molecular Epidemiological Study of Pyrazinamide-Resistance in Clinical Isolates of Mycobacterium tuberculosis from South India

Pyrazinamide (PZA) has been in use for almost 50 years as a first-line drug for short-course chemotherapy against Mycobacterium tuberculosis. In this study, PCR mediated automated DNA sequencing is used to check the prevalence of PZA resistance among treatment failure cases of pulmonary tuberculosis. Out of 50 clinical isolates examined, 39 had mutations in the pncA gene that encodes Pyrazinamidase, an enzyme required to activate PZA. Of these, 31 (79.5%) were localized to three regions of pncA. We found two isolates with hitherto unreported mutation at amino acid 26 (Ala→Gly) of pncA

Rapid One-Pot Synthesis of Polydopamine Encapsulated Carbon Anchored with Au Nanoparticles: Versatile Electrocatalysts for Chloramphenicol and Folic Acid Sensors

Designing and engineering nanocomposites with tailored physiochemical properties through teaming distinct components is a straightforward strategy to yield multifunctional materials. Here, we describe a rapid, economical, and green one-pot microwave synthetic procedure for the preparation of ternary nanocomposites carbon/polydopamine/Au nanoparticles (C/PDA/AuNPs; C = carbon nanotubes (CNTs), reduced graphene oxide (rGO)). No harsh reaction conditions were used in the method, as are used in conventional hydrothermal or high-temperature methods. The PDA unit acts as a non-covalent functionalizing agent for carbon, through π stacking interactions, and also as a stabilizing agent for the formation of AuNPs. The CNTs/PDA/AuNPs modified electrode exhibited excellent electrocatalytic activity to oxidize chloramphenicol and the resulting sensor exhibited a low detection limit (36 nM), wide linear range (0.1–534 μM), good selectivity (against 5-fold excess levels of interferences), appreciable reproducibility (3.47%), good stability (94.7%), and practicality (recoveries 95.0%–98.4%). Likewise, rGO/PDA/AuNPs was used to fabricate a sensitive folic acid sensor, which exhibits excellent analytical parameters, including wide linear range (0.1–905 μM) and low detection limit (25 nM). The described synthetic route includes fast reaction time (5 min) and a readily available household microwave heating device, which has the potential to significantly contribute to the current state of the field

Graphitic Carbon Nitride and IGZO Bio-FET for Rapid Diagnosis of Myocardial Infarction

Acute myocardial infarction (AMI), commonly known as a heart attack, is a life-threatening condition that causes millions of deaths every year. In this study, a transistor-based biosensor is developed for rapid and sensitive detection of cardiac troponin-I (cTnI), a diagnostic biomarker of AMI. A biosensing technique based on a field effect transistor (FET), which uses indium gallium zinc oxide (IGZO) as an excellent semiconducting channel, is integrated with nanosheet materials to detect cTnI. Porous carbon nitride (PCN) decorated with gold nanoparticles (Au NPs) is used as a bridge between the solid-state device and the biorecognition element. We demonstrate that this biosensor is highly sensitive and has an experimental limit of detection of 0.0066 ng/mL and a dynamic range of 0.01 ng/mL–1000 ng/mL. This is the first report of a semiconducting metal oxide FET cardiac biomarker sensor combined with PCN for the detection of cTnI. The reported compact microsystem paves the way for rapid and inexpensive detection of cardiac biomarkers

A pilot study on the infiltrating cells and cytokine levels in the tear of fungal keratitis patients

Aim: To determine the cellular profile and cytokine levels in the tear fluid of fungal keratitis patients. Materials and Methods: Tear samples were collected from six fungal keratitis patients (Group I) from active stages of the disease up to resolution. Tears collected from the following served as controls: uninfected fellow eye (Group II A) of Group I, patients undergoing cataract surgery (Group II B) and acute conjunctivitis (Group II C). The cellular profile was evaluated. Interleukines (IL-6, IL-8 and IL-1β) were estimated using sandwich enzyme immunoassay. Statistical analysis was carried out using nonparametric two-sample median test. Results: Polymorphonuclear leukocytes (PMN) were the predominant infiltrating cells in Group I. During the initial stages of fungal infection, levels of IL-6 and IL-8 in the tear samples were found to be significantly increased when compared with Group II A ( P = 0.019 for IL-6, P < 0.001 for IL-8). This was also true for IL -8 ( P = 0.008) levels in Group I and Group II B). While IL-6 levels decreased significantly towards healing, IL-8 remained slightly elevated even after healing. These cytokines were at the base level in Group II A. Lymphocytes and PMN were present in equal proportions in Group II C, which showed elevated levels of cytokines but not to the extent of Group I. Conclusion: This horizontal study indicates that understanding the nature of the inflammatory response in the tears of fungal keratitis patients is of considerable interest and warrants further investigations

Ruthenium and Nickel Molybdate-Decorated 2D Porous Graphitic Carbon Nitrides for Highly Sensitive Cardiac Troponin Biosensor

Two-dimensional (2D) layered materials functionalized with monometallic or bimetallic dopants are excellent materials to fabricate clinically useful biosensors. Herein, we report the synthesis of ruthenium nanoparticles (RuNPs) and nickel molybdate nanorods (NiMoO4 NRs) functionalized porous graphitic carbon nitrides (PCN) for the fabrication of sensitive and selective biosensors for cardiac troponin I (cTn-I). A wet chemical synthesis route was designed to synthesize PCN-RuNPs and PCN-NiMoO4 NRs. Morphological, elemental, spectroscopic, and electrochemical investigations confirmed the successful formation of these materials. PCN-RuNPs and PCN-NiMoO4 NRs interfaces showed significantly enhanced electrochemically active surface areas, abundant sites for immobilizing bioreceptors, porosity, and excellent aptamer capturing capacity. Both PCN-RuNPs and PCN-NiMoO4 NRs materials were used to develop cTn-I sensitive biosensors, which showed a working range of 0.1–10,000 ng/mL and LODs of 70.0 pg/mL and 50.0 pg/mL, respectively. In addition, the biosensors were highly selective and practically applicable. The functionalized 2D PCN materials are thus potential candidates to develop biosensors for detecting acute myocardial infractions

Axial Coordination Site-Turned Surface Confinement, Electron Transfer, and Bio-Electrocatalytic Applications of a Hemin Complex on Graphitic Carbon Nanomaterial-Modified Electrodes

Understanding the relation between the chemical bonding and the electron-transfer (ET) reaction of surface-confined hemin (a five-coordinated Fe-porphyrin-with-chlorine complex) is a special interest in the biomimicking studies of heme proteins. Owing to the difficulty in ET function, scanty electrochemical reports of hemin in aqueous solution were reported. It has been noticed that in most of the reported procedures, the sixth axial coordination position of the hemin complex has been unknowingly turned by attaching with water molecules (potential cycling in alkaline conditions or heating), solvents such as ethanol and dimethyl sulfoxide, and nitrogen-donating compounds that have helped for the heme ET reaction. In this work, a systematic effort has been taken to find out the contribution of hemin and its axial bond coordination with π–π interaction, hydrogen bonding, and hydrophobic binding systems toward the ET reaction. Various graphitic carbons such as graphitized mesoporous carbon (GMC), mesoporous carbon-hydrophilic and hydrophobic units, graphite nanopowder, graphene oxide, single-walled carbon, multiwalled carbon nanotube (MWCNT), and carboxylic acid-functionalized MWCNT (as a source for π–π interaction, hydrogen bonding, and hydrophobic environment) along with the amino functional group of chitosan (Chit; as an axial site coordinating system) have been tested by modifying them as a hemin hybrid on a glassy carbon electrode (GCE). In addition, a gold nanoparticle (Au_nano) system was combined with the above matrix as a molecular wiring agent, and its role was examined. A highly stable and well-defined redox peak at an apparent formal potential (<i>E</i>^o′) of −320 mV versus Ag/AgCl with the highest surface excess of 120 × 10^–10 mol cm^–2 was noticed with the GCE/Au_nano–GMC@hemin–Chit hybrid system, wherein all interactive features have been utilized. Omitting any of the individual interactions resulted in either decreased (with Au_nano) or nil current response. As applications, efficient bio-electrocatalytic reduction and sensing of dissolved oxygen and hydrogen peroxide have been demonstrated

Multiplexed sensing techniques for cardiovascular disease biomarkers- A review

Cardiovascular diseases (CVDs) are the number one cause of death worldwide, taking 17.9 million lives each year. The rapid, sensitive, and accurate determination of cardiac biomarkers is vital for the timely diagnosis of CVDs. For accurate diagnosis, dependence on a single biomarker is unreliable because each one has also been linked to other diseases. To overcome this problem, the multiplexed determination of two or more markers has emerged as a promising alternative to single-marker analysis. Over the last 5 years, research interest in the development of biosensors for targeting multiple cardiac markers has increased. In this study, we critically reviewed the various multiplexed biosensing approaches reported during the last 5 years, categorizing them by signal readouts. Prospective detection configurations, capture probes, electrode design strategies, electrode types, nanomaterials, reporter tags, and assay types were reviewed, tabulated, and critically discussed. Then, their advantages and limitations were highlighted. For each category, we provided our perspective as well as the overall critical discussion. Lastly, we summarized potential commercial multiplexed cardiac biosensors and commented on the challenges and future prospects for such sensors

Electrochemical sensors targeting salivary biomarkers: A comprehensive review

salama, khaled Nabil/0000-0001-7742-1282; Ceylan, Ayse Elcin/0000-0002-0591-6080; Wolfbeis, Otto S./0000-0002-6124-2842; Mani, PhD, MRSC, Veerappan/0000-0002-0756-7398WOS:000620153500008The analysis of salivary markers has grown into a promising non-invasive route for easy, safe, and pain-free monitoring and has the potential to alter the existing way of clinical diagnosis and management. Advancements in sensing technology, the arrival of novel materials, the innovative fabrication technologies, and sampling accuracy have made significant progress and establishing saliva as a fluid for routine analysis. Salivary biomarkers are useful to diagnose not only cardiovascular diseases, bacterial or viral infections but also cancer, diabetes, or Alzheimer's disease. in addition, saliva is analyzed in toxicology, forensic medicine and drug abuse. Electrochemical assays and sensors are well accepted tools because they allow for fast and cost-effective analysis. Nanomaterials, microfluidics, smartphones, paper-based, flexible and wearable devices have made significant advancements in saliva analysis. This review discusses the recent progress made in electrochemical methodologies for detecting salivary biomarkers. (C) 2020 Elsevier B.V. All rights reserved.King Abdullah University of Science and Technology (KAUST), Saudi ArabiaKing Abdullah University of Science & TechnologyThis work was supported financially by King Abdullah University of Science and Technology (KAUST), Saudi Arabia