Utkarsh Jain

An electrochemical sensor for detection of neurotransmitter-acetylcholine using metal nanoparticles, 2D material and conducting polymer modified electrode

An essential biological sensor for acetylcholine (ACh) detection is constructed by immobilizing enzymes, acetylcholinesterase (AChE) and choline oxidase (ChO), on the surface of iron oxide nanoparticles (Fe2O3NPs), poly(3,4-ethylenedioxythiophene) (PEDOT)-reduced graphene oxide (rGO) nanocomposite modified fluorine doped tin oxide (FTO). The qualitative and quantitative measurements of nanocomposites properties were accomplished by scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). This prepared biological sensor delineated a wide linear range of 4.0nM to 800μM with a response time less than 4s and detection limit (based on S/N ratio) of 4.0nM. The sensor showed perfect sensitivity, excessive selectivity and stability for longer period of time during storage. Besides its very high-sensitivity, the biosensor has displayed a low detection limit which is reported for the first time in comparison to previously reported ACh sensors. By fabricating Fe2O3NPs/rGO/PEDOT modified FTO electrode for determining ACh level in serum samples, the applicability of biosensor has increased immensely as the detection of the level neurotransmitter is first priority for patients suffering from memory loss or Alzheimers disease (AD).

Glycated hemoglobin detection with electrochemical sensing amplified by gold nanoparticles embedded N-doped graphene nanosheet.

In the diabetic patients the level of glucose must be determined without any short term fluctuations. The level of Glycated hemoglobin (HbA1c) is accordingly examined for checking diabetes mellitus. HbA1c is considered one of the primarily factor to discern the concentration of average plasma glucose over a long-drawn-out period. In our work, we describe a construction of biosensor which is based on fructosyl amino-acid oxidase (FAO) immobilized nitrogen-doped graphene/gold nanoparticles (AuNPs)/fluorine doped tin oxide (FTO) glass electrode. This constructed biosensor exhibits a wide linear range of 0.3 to 2000μM in response to HbA1c at +0.2V. Consequently, the detection limit of 0.2μM and good stability (4 months) were achieved. The electrocatalytic activity of this sensor was good as a result of synergistic effect of graphene and AuNPs (2D and 0D nanomaterials). The charge transfer resistance was decreased which was observed by electrochemical impedance spectroscopy (EIS) study. The graphene/AuNPs composites film reveals a distinguished electrochemical response to fructosyl valine (FV) which demonstrates a promising application for electrochemical detection of HbA1c in human blood samples.

Electrochemical biosensor with graphene oxide nanoparticles and polypyrrole interface for the detection of bilirubin

A bilirubin biosensor was fabricated by immobilization of bilirubin oxidase (BOx) on a graphene oxide nanoparticle (GONP) decorated polypyrrole (Ppy) layer electrochemically deposited onto a fluorine doped tin oxide (FTO) glass plate. The enzyme electrode (BOx/GONP@Ppy/FTO), Ag/AgCl as the standard electrode and platinum as the auxiliary electrode were assembled using a potentiostat to develop an amperometric bilirubin biosensor. The characterization of the enzyme electrode was fulfilled using Raman spectroscopy, scanning electron microscopy, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The biological sensor demonstrated a response at pH 7.5 and 30 °C in only 2 s which was optimum once polarized at +0.2 V vs. Ag/AgCl. The biosensor’s limit of detection (LOD) and required limit of quantification (LOQ) was calculated as 0.1 nM (S/N = 3) and 2.6 nM, respectively. The electrocatalytic reaction illustrated a linear response over the bilirubin/substrate concentration in the range of 0.01 to 500 μM. The half-life of the biosensor is 150 days, during which it could be reused 100 times after keeping the biosensor at 4 °C. The bilirubin levels measured in serum samples of both healthy and jaundice afflicted persons correlated well with the popular colorimetric method, the coefficient of determination (R2) being 0.998.

An overview of adjuvants utilized in prophylactic vaccine formulation as immunomodulators

ABSTRACT Introduction: Development of efficient and cost effective vaccines have been recognized as the primary concern to improve the overall healthcare in a country. In order to achieve this goal, more improved and powerful adjuvants need to be developed. Lacking in the self-adjuvanting immuno-modulatory constituents, vaccines exhibit lower immunogenicity. Combining potent adjuvants with vaccines is the most appropriate method to enhance the efficacy of the vaccines. Hence, this review is focussed on the most potent adjuvants for the formulation of vaccines. Areas covered: This review focuses on Oil-based emulsions, Mineral compounds, Liposomes, Bacterial products, ISCOMs and most recently used nanomaterials as adjuvants for enhancing the antigenicity of vaccines. Furthermore, this review explains the immunological response elicited by various particles. Moreover, case studies are incorporated providing an in depth analyses of various adjuvant-containing vaccines which are currently used. Expert commentary: Enhanced fundamental knowledge about the adjuvants and their immuno-stimulatory capabilities and delivery mechanisms will facilitate the rational designing of prophylactic vaccines with better efficacy.

Potential biomarkers for effective screening of neonatal sepsis infections: An overview

Neonatal sepsis, a clinical disorder developed by bacterial blood stream infections (BSI) in neonates, is one of the serious global public health problems that must be addressed. More than one million of the estimated global newborn deaths per year are occurred due to severe infections. The genesis of the infection is divided into early-onset sepsis (EOS) and late-onset sepsis (LOS) of the disease. The clinical complications of neonatal sepsis may be associated with bronchopulmonary dysplasia, ductus arteriosus and necrotizing enterocolitis. The clinical diagnosis and treatment of neonatal sepsis is highly complicated. Over the past few years distinct biomarkers have been identified. Most widely used biomarkers are C-reactive protein, Procalcitonin (PCT) and Serum amyloid A (SAA). Until recently, many potential biomarkers including Cell Surface antigens and Bacterial surface antigens and genetic biomarkers are being investigated. Protein biomarkers, cytokines and chemokines are getting much interest for identification of neonatal sepsis infection.

Detection of glycated hemoglobin with voltammetric sensing amplified by 3D-structured nanocomposites

Glycated hemoglobin (HbA1c), a marker for glycine level in blood, while detecting over a long period of time (up to 2-3 months) shows consistency. Therefore, HbA1c has been mostly used and indeed an established test for monitoring the glycemic control in persons suffering from diabetes. 3D-structured reduced graphene oxide (rGO), multiwalled carbon nanotubes (MWCNT) and platinum nanoparticles (PtNPs) composite (PtNPs/rGO-MWCNT) were synthesized and used as interface for the development of an electrochemical HbA1c biosensor. The network structure of rGO-MWCNT nanocomposite provides more active sites for Pt deposition and the synergistic effect of rGO, MWCNTs and PtNPs significantly improved the electrochemical performance of the working electrode. The structure of PtNPs/rGO-MWCNT nanocomposite was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance study (EIS). This biosensor exhibited a response time of less than 3s, a wide linear concentration range of 0.05-1000μM with detection limit of 0.1μM, good repeatability and satisfactory reproducibility. The biosensor retained 50% of its initial response after 12 weeks at 25°C. The proposed biosensor was successfully applied for the determination of HbA1c concentration in human blood samples with recoveries between 93.7 and 98.3%.

Construction of an amperometric glycated hemoglobin biosensor based on Au–Pt bimetallic nanoparticles and poly (indole-5-carboxylic acid) modified Au electrode

The glucose level measurement in the diabetic patient plays a vital role in identification of the treatments going on and it also provides the control over the diabetics. A new electrochemical sensing device was constructed for determination of glycated hemoglobin (HbA1c) in whole blood samples. Fructosyl amine oxidase (FAO) was bioconjugated onto hybrid nanocomposite i.e., gold nanoparticles-platinum nanoparticles (AuNPs-PtNPs) and poly indole-5-carboxylic acid (PIN5COOH), deposited electrochemically on gold electrode. Bimetallic nanoparticles not only show their individual properties but also provides the synergistic effect between the two noble metal nanoparticles. AuNPs-PtNPs shown as an amplified sensing interface at lower voltage which makes the sensor more sensitive and specific. The FAO/AuNPs-PtNPs onto PIN5COOH/Au electrode shows a promising future in diagnosis of HbA1c and diabetes management. The novel sensor formed has good accuracy, selectivity, sensitivity, precision and reliability. In addition to these, it showed good storage stability and retained 50% of its initial activity within 12 weeks at 4°C.

Helicobacter pylori VacA, a distinct toxin exerts diverse functionalities in numerous cells: An overview: XXXX

Helicobacter pylori, gastric cancer‐causing bacteria, survive in their gastric environment of more than 50% of the world population. The presence of H. pylori in the gastric vicinity promotes the development of various diseases including peptic ulcer and gastric carcinoma. H. pylori produce and secret Vacuolating cytotoxin A (VacA), a major toxin facilitating the bacteria against the host defense system. The toxin causes multiple effects in epithelial cells and immune cells, especially T cells, B cells, and Macrophages.

Zinc Oxide Tetrapods Based Biohybrid Interface for Voltammetric Sensing of Helicobacter pylori

Helicobacter pylori is a Gram-negative, spiral shaped, microaerophilic bacteria that colonizes human gastric mucosa and causes various gastric diseases. In this work, the utilization of ion irradiated zinc oxide tetrapods (ZnO-T) based biohybrid interface accentuates the development of an electrochemical immunosensor for the fast and sensitive detection of H. pylori. After coating of (ZnO-T) over the surface of screen printed electrode (SP-AuE) through electrodeposition, the ZnO-T/SP-AuE was irradiated with N2+ ion of energy 100 keV. The ion irradiation significantly enhances the conductivity of ZnO-T coated SP-AuE. The revamped SP-AuE is further used for establishing an immunosensor interface based upon immobilization of the CagA antigen on ZnO-T electrodeposited over the surface of SP-AuE. The sensing interface demonstrated good linearity (0.2 ng/mL to 50 ng/mL) and limit of detection (0.2 ng/mL). The ion beam irradiated ZnO-T based immunosensor showed significantly high conductivity and enhanced the analytical properties of the working electrode in terms of the sensitivity, detection limit, and response time. A study on the comparison of irradiated and pristine electrode is performed for amperometric sensing of H. pylori. In addition, the significance of work conducted on ion irradiated ZnO-T based interfaces provides a basis of further development of electrochemical immunosensors.

A novel electrochemical comparative sensing interface of MgO nanoparticles synthesized by different methods

Recent advancements in nanotechnology, for the biosynthesis of metal nanoparticles through enormous techniques, showed multidimensional developments. One among many facets of nanotechnology is to procure and adopt new advancements for green technology over chemical reduction synthesis. This adaptation for acquiring green nanotechnology leads us to a new dimension of nanobiotechnology. In order to imply one such efforts, in this study the emphasis is being laid on the synthesis of MgO nanoparticles using green technology and eliminating chemical reduction methods. Different characterization techniques such as UV–Vis spectroscopy, transmission electron microscopy, and dynamic light scattering were used to carry out the experiments. The average size of MgO nanoparticles were obtained in the range of 85–95 nm, when synthesized by various sources. The extracts of plants were capable of producing MgO nanoparticles efficiently and exhibited good results during cyclic voltammetry and electrochemical impedance spectroscopy study. The electrode modified with MgO nanoparticles (plant extract) showed good stability (90 days) and high conductivity. This study reports cost-effective and environment-friendly method for synthesis of MgO nanoparticles using plant extracts. The process is rapid, simple, and convenient and can be used as an alternative to chemical method.