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 Alzheimer's disease (AD).
•Fe2O3NPs/PEDOT-rGO nanocomposite film explored for acetylcholine biosensing.•Estimation of acetylcholine in serum samples of Alzheimer's patients.•Bioelectrode studied using SEM, CV and EIS and exhibit high sensitivity.
Background
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.
Methods
This review describes the diverse functionalities of protein toxin VacA. The specific objective of this review is to address the overall structure, mechanism, and functions of VacA in various cell types. The recent advancements are summarized and discussed and thus conclusion is drawn based on the overall reported evidences.
Results
The searched articles on H. pylori VacA were evaluated and limited up to 66 articles for this review. The articles were divided into four major categories including articles on vacA gene, VacA toxin, distinct effects of VacA toxin, and their effects on various cells. Based on these studies, the review article was prepared.
Conclusions
This review describes an overview of how VacA is secreted by H. pylori and contributes to colonization and virulence in multiple ways by affecting epithelial cells, T cells, Dendritic cells, B cells, and Macrophages. The reported evidence suggests that the comprehensive outlook need to be developed for understanding distinctive functionalities of VacA.
Biosensors have acquired much importance in drug discovery, medical diagnostics, food safety, defense, security, and monitoring of environmental conditions. Furthermore, there has been great progress ...in the potential applications of advanced nanomaterials in biosensors. Every year there are several advances in sensing techniques that can be attributed to nanomaterials, biorecognition elements, or their related fabrication techniques. The further development of nanotechnology-based sensors provides a wide variety of opportunities to modern research. Advanced nanomaterials can provide remarkable optical, electrical, mechanical, and catalytic properties. For example, transition metals and organic polymers have been used in the fabrication of powerful, sensitive, and precise biosensors. The distinctive properties of advanced nanomaterials have been widely incorporated into biosensors. However, fabrication techniques also play important roles in the development of these devices. Therefore, we present a review of some of the advanced nanomaterials that have been widely used over the last few years and discuss their fabrication techniques. The focus of this review is to provide a directional perspective of recently fabricated advanced nanomaterial-based biosensors in the diagnosis of various diseases.
Abstract
The gastric colonization of human hosts by
Helicobacter pylori (H. pylori)
increases the risk of developing gastritis, ulcers and gastric cancer. To detect
H. pylori,
a nanohybrid-based BabA ...immunosensor is developed herein. BabA is an outer membrane protein and one of the major virulence factors of
H. pylori
. To design the immunosensor, an Au electrode is loaded with palladium nanoparticles (Pd
nano
) by electrodeposition to generate reduced graphene oxide (rGO)/poly(3,4-ethylenedioxythiophene) (PEDOT). The immobilization of these nanostructured materials imparts a large surface area and electroconductivity to bio-immune-sensing molecules (here, the BabA antigen and antibodies). After optimization, the fabricated immunosensor has the ability to detect antigens
(H. pylori)
in a linear range from 0.2 to 20 ng/mL with a low LOD (0.2 ng/mL). The developed immunosensor is highly specific, sensitive and reproducible. Additionally, in silico methods were employed to better understand the hybrid nanomaterials of the fabricated Pd
nano
/rGO/PEDOT/Au electrode. Simulations performed by molecular docking, and Metropolis Monte Carlo adsorption studies were conducted. The results revealed that the hybrid nanomaterials exhibit a stable antigen–antibody complex of BabA, yielding the lowest binding energy in relation to the electrode materials, emphasizing the functionality of the constructed electrodes in the electrochemical immunosensor.
We describe a method that uses total internal reflection at the water–air interface inside a large, transparent tank, to measure the interface’s deflections. Using this configuration, we obtain an ...optical set-up where the liquid surface acts as a deformable mirror. The set-up is shown to be extremely sensitive to very small disturbances of the reflecting water surface, which are detected by means of visualising the reflections of a reference pattern. When the water surface is deformed, it reflects a distorted image of the reference pattern, similar to a synthetic Schlieren set-up. The distortions of the pattern are analysed using a suitable image correlation method. The displacement fields thus obtained correlate to the local spatial gradients of the water surface. The gradient fields are integrated in a least-squares sense to obtain a full instantaneous reconstruction of the water surface. This method is particularly useful when a solid object is placed just above water surface, whose presence makes the liquid surface otherwise optically inaccessible.
Graphical abstract
Calcium is a necessary biochemical messenger in neuromuscular transmission, muscle compression, and hormonal secretion processes. Calcium binds with a multifunctional intermediate calcium-binding ...sensor protein calmodulin with a significantly higher affinity. This presented work introduces an electrochemical biosensor for the detection of sepsis by utilizing calmodulin protein on the sensing interface. The sensing platform is assembled on the gold screen-printed electrode (SPE) modified with platinum nanoparticles (PtNPs) and functionalized with chitosan. Furthermore, the calmodulin protein was electrodeposited on the chitosan functionalized SPE. The electrochemical measurements were recorded for the rapid screening of Ca
2+
ions in various samples including bacterial cells and real serum samples. The serum ionized calcium is a biomarker for the detection of sepsis in newborns. The developed biosensor exhibits high sensitivity, low-cost development, and rapid results. The detection limit and sensitivity of the sensor were obtained as 1 nM and 0.51 µA/µM respectively.
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.
Internet connectivity is now considered to be a basic human right and in this era of information technology, more efficient ways of browsing the web are being found. The most popular search engine, ...Google uses its ‘Page Rank Algorithm’ for its searches. In this paper, we aim to find out a more efficient way of searching the web and better organising the search result based on the categories of the pages. The results of the proposed algorithm are compared with the existing Page Rank algorithms, which include the original PageRank Algorithm and a Weighted PageRank Algorithm. The results obtained in this paper have been experimentally compared with the data of the above-mentioned algorithms using comparison graphs.
•Human health is seriously threatened by the emerging global pandemic of antibiotic resistance, which is mostly caused by the rise of drug resistance ESKAPE pathogens.•Bacteriophages are excellent ...weapon against antibiotic-resistant pathogens because of its host specificity, rapid evolution, self-replication, and environmental stability.•Phage-based biosensors are compared with traditional diagnostic methods.•Phage- based biosensor is innovative approach for detection of ESKAPE pathogens, it offers better selectivity, accuracy, specificity, than conventional methods.•Insights into the potential effects of phage-based biosensors on public health regulations and clinical practice.
Global health is seriously threatened by an increase in antibiotic resistance among ESKAPE pathogens- E- E. faecium, S- S.aureus, K- K.pneumoniae, A-A.baumannii, P- P.aeruginosa, and E-Enterobacter. The resistance of many bacteria to traditional antibiotics is increasing, making the search for novel approaches critical. In order to minimize the effect of these diseases, early detection, diagnosis, and treatment are important. However, there are drawbacks to traditional detection techniques such molecular-based, biochemical, and microbiological assays. These include the inability to detect on-site, as well as their time-consuming, expensive, and labour-intensive nature. Viral agents that target bacteria exclusively, known as bacteriophages, have shown promise in combating over infections resistant to antibiotics. Bacteriophage-based biosensors are adaptable to many environmental conditions and offer special features such as host specificity and ability to identify active infections. They're very accurate, very specific, and have quick assay times, which makes them beneficial tools for detection. Also, phages are more easily produced than antibodies and can withstand high pH, temperature, and chemical solvents. The potential of bacteriophage-based biosensors in the fight against ESKAPE pathogens is highlighted by this review. Bacteriophage-based biosensors provide simplified detection processes in contrast to conventional approaches, which makes them invaluable in environmental and clinical situations. Numerous platforms, including electrochemical, magnetoelastic, quartz crystal microbalance, and surface plasmon resonance sensors, being investigated for their potential use to detect pathogenic bacteria in a range of sample types.
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