Electrochemically grafted gallic acid-chitosan: a metal-free redox platform for regiospecific oligopeptide-viral spike protein interaction.

Electrochemical grafting of gallic acid with chitosan (EgGC) voltammetrically deposited on a multitude of substrates exhibiting reversible oxidoreduction suitable for sensor construction is reported. A bioreceptor customized from the fragment antigen binding region of SARS-CoV-2 neutralizing antibodies immobilized on an EgGC matrix supported the selective/specific electrochemical signal transduction with respect to different viral loads (femtogram level) of SARS-CoV-2.

β-Cyclodextrin-Tethered Butein, a Greener Redox-Active Biomaterial for Electrochemical Enzymatic Sensing of Sialic Acid.

Biocompatible, industrially scalable, and opto/electrochemically active biomaterials are promising for biosensor platform design and application. Herein, cyclic oligosaccharide, β-cyclodextrin (BCD), is conjugated with Butein, a chalcone-type polyphenol, via dehydration reaction of the hydroxyl groups of BCD and the benzoyl ring of Butein. Functional group changes in the conjugated BCD-Butein were comprehensively studied using UV-visible absorbance, Fourier transform-infrared, and X-ray photoelectron spectroscopic techniques.

Buteinylated-hafnium oxide bionanoparticles for electrochemical sensing of wogonin.

Hybridizing biomolecules with metal oxide nanostructures possessing inherent optical emission and electrochemical functionality is advantageous for external mediator-free analytical applications. This work demonstrates the ultrasonochemical synthesis of hafnium oxide (HfO) nanoparticles and their combination with butein, a chalcone type polyphenol, for the direct electrochemical detection of active herbaceuticals. The underlying hybridization chemistry between HfO and butein within the bio-nano interface is comprehensively investigated using ultraviolet diffuse reflectance, X-ray diffraction, Fourier-transform infrared, and X-ray photoelectron spectroscopic techniques.

Label-free genosensing of dengue serotypes with an electrodeposited reduced graphene oxide-tris(bipyridine)ruthenium(II).

Constructing a label-free electrochemical transducer platform without compromising inherent biocompatibility against specific bioreceptor remains challenging, particularly probing nucleic acid hybridization at electrode interface without external redox-mediator. Here, we show that electrochemically reduced graphene oxide-tris(bipyridine)ruthenium(II) (ErGO-TBR) nanosheets electrodeposited on carbon screen printed electrode can quantify hybridization of clinically important target sequences specific to serotypes of dengue virus (DENV) non-structural 1 (NS1) protein. Different variables including deposition potential, time, and electrolytic composition were optimized for fabrication of label-free transducer platform.

Emerging trends in point-of-care biosensing strategies for molecular architectures and antibodies of SARS-CoV-2.

COVID-19, a highly contagious viral infection caused by the occurrence of severe acute respiratory syndrome coronavirus (SARS-CoV-2), has turned out to be a viral pandemic then ravaged many countries worldwide. In the recent years, point-of-care (POC) biosensors combined with state-of-the-art bioreceptors, and transducing systems enabled the development of novel diagnostic tools for rapid and reliable detection of biomarkers associated with SARS-CoV-2. The present review thoroughly summarises and discusses various biosensing strategies developed for probing SARS-CoV-2 molecular architectures (viral genome, S Protein, M protein, E protein, N protein and non-structural proteins) and antibodies as a potential diagnostic tool for COVID-19.

DNA-functionalized carbon quantum dots for electrochemical detection of pyocyanin: A quorum sensing molecule in Pseudomonas aeruginosa.

The electrochemical biosensing strategy for pyocyanin (PYO), a virulent quorum-sensing molecule responsible for Pseudomonas aeruginosa infections, was developed by mimicking its extracellular DNA interaction. Calf thymus DNA (ct-DNA) functionalized amine-containing carbon quantum dots (CQDs) were used as a biomimetic receptor for electrochemical sensing of PYO as low as 37 nM in real urine sample. The ct-DNA-based biosensor enabled the selective measurement of PYO in the presence of other interfering species.

Electropolymerized Melamine on Electrochemically Reduced Graphene Oxide: Growth Mechanistics, Electrode Processing, and Amperometric Sensing of Acyclovir.

Metal-free, cost-efficient, redox-active electrode materials, combining graphene derivatives with nitrogen-rich polymelamine (PM), are widely explored as an interface layer for electrocatalysis and an electrochemical sensor platform. However, conventional chemical routes often yield derivatives of PM suffering from impaired redox behavior, restricting their electron-transfer kinetics. Herein, an optimal potentiodynamic method has been established to electrodeposit PM on electrochemically reduced graphene oxide (ErGO).

Bioadhesive Gauze Embedded with Chitosan-Butein Bioconjugate: A Redox-Active pH Sensor Platform.

With the ever-growing global wound care market, demand for robust redox-active healthcare material is obvious for the construction of wearable sensor platforms. Surface reactive functional group-rich material like chitosan holds huge potential for electrochemical biosensor application. Herein, a metal-free redox-active chitosan-butein (CSB) bioconjugate is processed into epidermal bioadhesive electrode material useful for pH sensors promising toward wound site analysis.

Peptide-based direct electrochemical detection of receptor binding domains of SARS-CoV-2 spike protein in pristine samples.

RNA isolation and amplification-free user-friendly detection of SARS-CoV-2 is the need of hour especially at resource limited settings. Herein, we devised the peptides of human angiotensin converting enzyme-2 (ACE-2) as bioreceptor at electrode interface for selective targeting of receptor binding domains (RBD) of SARS-CoV-2 spike protein (SP). Disposable carbon-screen printed electrode modified with methylene blue (MB) electroadsorbed graphene oxide (GO) has been constructed as cost-efficient and scalable platform for ACE-2 peptide-based SARS-CoV-2 detection.

Electrochemical and DFT studies of andrographolide on electrochemically reduced graphene oxide for anti-viral herbaceutical sensor.

Herbal extracts are re-emerging as potential remedies for various vector-borne diseases. Amongst several phytochemicals, active ingredients of Andrographis paniculata extract is regarded as promising for dengue fever, caused by Aedes species. However, fingerprinting the active phytochemicals from herbal extracts are often relies on sophisticated analytical techniques which are not universally accessible.

A machine learning-based approach to determine infection status in recipients of BBV152 (Covaxin) whole-virion inactivated SARS-CoV-2 vaccine for serological surveys.

Data science has been an invaluable part of the COVID-19 pandemic response with multiple applications, ranging from tracking viral evolution to understanding the vaccine effectiveness. Asymptomatic breakthrough infections have been a major problem in assessing vaccine effectiveness in populations globally. Serological discrimination of vaccine response from infection has so far been limited to Spike protein vaccines since whole virion vaccines generate antibodies against all the viral proteins.

Rational design of effective solid-state electrochemiluminescence platform of Gold@Polyluminol nanocomposite as an ultrasensitive immuno-probe for selective detection of prostate specific antigen.

An electrodeposited gold@poly-luminol nanocomposite on glassy carbon electrode (Au@PL-NC/GCE) has been developed and demonstrated as solid-state electrochemiluminescence (ECL) immunosensor platform for prostate specific antigen (PSA) sensing. In-situ electro-generated reactive oxygen species (ROS) from oxygen reduction reaction in oxygen saturated PBS (pH 7.4) acts as sole co-reactant augmenting the signal transduction.

Chitosan grafted butein: A metal-free transducer for electrochemical genosensing of exosomal CD24.

Metal-free cost-efficient biocompatible molecules are beneficial for opto-electrochemical bioassays. Herein, chitosan (CS) conjugated butein is prepared via graft polymerization. Structural integrity between radical active sites of CS and its probable conjugation routes with reactive OH group of butein during grafting were comprehensively studied using optical absorbance/emission property, NMR, FT-IR and XPS analysis.

Insights from a Pan India Sero-Epidemiological survey (Phenome-India Cohort) for SARS-CoV2.

To understand the spread of SARS-CoV2, in August and September 2020, the Council of Scientific and Industrial Research (India) conducted a serosurvey across its constituent laboratories and centers across India. Of 10,427 volunteers, 1058 (10.14%) tested positive for SARS-CoV2 anti-nucleocapsid (anti-NC) antibodies, 95% of which had surrogate neutralization activity.

State-of-Art Bio-Assay Systems and Electrochemical Approaches for Nanotoxicity Assessment.

Innovations in the field of nanotechnology, material science and engineering has rendered fruitful utilities in energy, environment and healthcare. Particularly, emergence of surface engineered nanomaterials offered novel varieties in the daily consumables and healthcare products including therapeutics and diagnostics. However, the nanotoxicity and bioactivity of the nanomaterials upon interaction with biological system has raised critical concerns to individual as well as to the environment.

Impact of aminated carbon quantum dots as a novel co-reactant for Ru(bpy): resolving specific electrochemiluminescence for butein detection.

Development of novel nanomaterial-based co-reactant is highly desired for enhancing ECL intensity and widespread analytical applications. Herein, we report the distinct role of amine-functionalized carbon quantum dots (f-CQDs) as a co-reactant, for the first time, augmenting the ECL property of Ru(bpy) and demonstrating for biopharmaceutical (butein) detection. Unlike conventional co-reactants like tripropylamine (TPrA), 2-(dibutylamino)ethanol (DBAE), and pristine CQDs, the f-CQDs as a co-reactant yield superior ECL of Ru(bpy).

Opto-electrochemical functionality of Ru(II)-reinforced graphene oxide nanosheets for immunosensing of dengue virus non-structural 1 protein.

Transforming the structural and functional properties of carbon nanostructures are highly beneficial for healthcare diagnostics. This research demonstrates the functionalization of opto-electrochemically active ruthenium bipyridine complex (Ru(II)) on the surface of graphene oxide (GO), enabling a dual-functional immunoprobe for the detection of non-structural 1 (NS1) protein, a dengue biomarker. Structural investigations reveals that Ru(II) has intermolecular bonding with functional groups of GO.

Chitosanylated MoO-Ruthenium(II) Nanocomposite as Biocompatible Probe for Bioimaging and Herbaceutical Detection.

Hybrid nanomaterials with inherent physicochemical properties and cytocompatibility are beneficial for healthcare utilities. This paper demonstrates the hybridization of transition-metal oxide (molybdenum trioxide, MoO), optoelectrochemically active dye complex (Ru(II)), and biopolymer (chitosan, CS) into a single nanosystem. The asafetida-resin-mediated green synthesis of MoO nanoparticles (MoO NPs) enabled chemical adsorption of Ru(II) and CS.

Amygdalin-Functionalized Carbon Quantum Dots for Probing β-Glucosidase Activity for Cancer Diagnosis and Therapeutics.

A fluorescence active nanosystem capable of targeting specific receptors of cancer cells with or without a biorecognition element is advantageous for biosensor studies. Herein, a naturally occurring anticancer drug, amygdalin (synthetic form: Laetrile, a misnomer: vitamin B17), has been modified on the surface of carbon quantum dots, prepared by a hydrothermal method, to probe β-glucosidase activity. Despite its cyanide toxicity, amygdalin is recently revived to be an anticancer molecule, and the risk factor can be optimized by understanding its binding efficiency with β-glucosidase in the cancer cells.

Graphene-based nanocomposites for sensitivity enhancement of surface plasmon resonance sensor for biological and chemical sensing: A review.

Surface plasmon resonance (SPR) offers exceptional advantages such as label-free, in-situ and real-time measurement ability that facilitates the study of molecular or chemical binding events. Besides, SPR lacks in the detection of various binding events, particularly involving low molecular weight molecules. This drawback ultimately resulted in the development of several sensitivity enhancement methodologies and their application in the various area.

RF magnetron sputtering mediated NiTi/Ag coating on Ti-alloy substrate with enhanced biocompatibility and durability.

Mechanically robust, biocompatible and corrosion resistant Ag doped NiTi (NiTi/Ag) coatings were formed on implant grade commercially pure titanium substrates by R.F. magnetron sputtering.

Methylene Blue-Fortified Molybdenum Trioxide Nanoparticles: Harnessing Radical Scavenging Property.

A hybrid nanosystem with impeccable cellular imaging and antioxidant functionality is demonstrated. The microwave irradiation-derived molybdenum trioxide nanoparticles (MoO NPs) were surface-functionalized with the cationic dye molecule, methylene blue (MB), which enables superior UV-visible absorbance and fluorescence emission wavelengths potential for bioimaging. The radical scavenging property of the pristine MoO NPs and MoO-MB NPs were studied in vivo using Caenorhabditis elegans as the model system.

Amperometric determination of As(III) and Cd(II) using a platinum electrode modified with acetylcholinesterase, ruthenium(II)-tris(bipyridine) and graphene oxide.

The authors describe an amperometric biosensor for the determination As(III) and Cd(II) based on the inhibition of the enzyme acetylcholineesterase (AChE). A platinum electrode was modified with ruthenium(II)-tris(bipyridyl), graphene oxide and AChE and then showed redox peaks at 0.06 and 0.

Chemically synthesized butein and butin: Optical, structure and electrochemical redox functionality at electrode interface.

Progress in the development of phytochemistry has delivered advancement in materials functionality for range of inter/trans-disciplinary application. Here, we investigated the structural functionality of chemically synthesized phytoconstitutent, chalcone (butein) and flavanone (butin). Photoactive and electroactive behavior of butein and butin were comprehensively studied using UV-vis absorbance, photoluminescence and cyclic voltammetric techniques.

Ruthenium bipyridine sensitized MoO multifunctional nanostructures: Study of opto-electrochemical properties, biocompatibility and bioimaging.

Simple and versatile methodology to synthesize hybrid nanostructures with multi-functionality for device application is advantageous. Herein, we report the synthesis of MoO nanostructures integrated with [Ru(bpy)] and PEGylation to obtain hybrid MoO-[Ru(bpy)] nanostructures. Chemically interacted [Ru(bpy)] provides optical and electrochemical properties to the hybrid structures.