An electrochemical immunosensing of electrochemically modified carbon cloth electrode based on functionalized gold nanoparticle-Prussian blue for the detection of aflatoxin B1 in vegetable oil industry

This study developed an electrochemical immunosensor for the detection of aflatoxin B1 (AFB1) in vegetable oil, based on an electrochemical modified carbon cloth (EMCC) electrode modified with a composite functional layer of cross-linked o-aminothiophenol functionalized AuNPs (o-ATP@AuNPs)/Prussian Blue (PB). The EMCC electrode substrate was prepared by modifying carbon cloth through electrochemical methods to increase its surface area, which allowed for the effective deposition of o-ATP@AuNPs/PB composite functional layer and improved the conductivity of the electrode material. The synergistic effect of o-ATP@AuNPs and PB significantly enhanced the sensitivity of the electrochemical sensor. Additionally, the AuS bond between L-Cysteine (L-Cys) and o-ATP@AuNPs improved the stability of the sensing interface. Under optimal conditions, the BSA/anti-AFB1/L-Cys/o-ATP@AuNPs/PB/EMCC sensor was able to detect AFB1 in the range of 0 to 20 ng mL-1 using square wave voltammetry (SWV), with a detection limit of 0.015 ng mL-1. The proposed sensor holds promise for future applications in the sensitive detection of AFB1 in vegetable oils.

Polysaccharides for Medical Technology: Properties and Applications

Over the past decade, the use of polysaccharides has gained tremendous attention in the field of medical technology. They have been applied in various sectors such as tissue engineering, drug delivery system, face mask, and bio-sensing. This review article provides an overview and background of polysaccharides for biomedical uses. Different types of polysaccharides, for example, cellulose and its derivatives, chitin and chitosan, hyaluronic acid, alginate, and pectin are presented. They are fabricated in various forms such as hydrogels, nanoparticles, membranes, and as porous mediums. Successful development and improvement of polysaccharide-based materials will effectively help users to enhance their quality of personal health, decrease cost, and eventually increase the quality of life with respect to sustainability.

Application of nickel chitosan nanoconjugate as an antifungal agent for combating Fusarium rot of wheat

Agro-researchers are endlessly trying to derive a potential biomolecule having antifungal properties in order to replace the application of synthetic fungicides on agricultural fields. Rot disease often caused by Fusarium solani made severe loss of wheat crops every year. Chitosan and its metallic nano-derivatives hold a broad-spectrum antifungal property. Our interdisciplinary study deals with the application of nickel chitosan nanoconjugate (NiCNC) against Fusarium rot of wheat, in comparison with chitosan nanoparticles (CNPs) and commercial fungicide Mancozeb. CNPs and NiCNC were characterized on the basis of UV–Vis spectrophotometry, HR-TEM, FESEM, EDXS and FT-IR. Both CNPs and NiCNC were found effective against the fungal growth, of which NiCNC at 0.04 mg/mL showed complete termination of F. solani grown in suitable medium. Ultrastructural analysis of F. solani conidia treated with NiCNC revealed pronounced damages and disruption of the membrane surface. Fluorescence microscopic study revealed generation of oxidative stress in the fungal system upon NiCNC exposure. Moreover, NiCNC showed reduction in rot disease incidence by 83.33% of wheat seedlings which was further confirmed through the observation of anatomical sections of the stem. NiCNC application helps the seedling to overcome the adverse effect of pathogen, which was evaluated through stress indices attributes.

Marine Biological Macromolecules as Matrix Material for Biosensor fabrication

The Ocean covers two-third of our planet and has great biological heterogeneity. Marine organisms like algae, vertebrates, invertebrates, and microbes are known to provide many natural products with biological activities as well as potent sources of biomaterials for therapeutic, biomedical, biosensors, and climate stabilization. Over the years, the field of biosensors have gained huge attention due to their extraordinary ability to provide early disease diagnosis, rapid detection of various molecules and substances along with long term monitoring. This review aims to focus on the properties and employment of various biomaterials (Carbohydrate polymers, proteins, polyacids etc) of marine origin such as Alginate, Chitin, Chitosan, Fucoidan, Carrageenan, Chondroitin Sulfate (CS), Hyaluronic acid (HA), Collagen, marine pigments, marine nanoparticles, Hydroxyapatite (HAp), Biosilica, lectins, and marine whole cell in the design and development of biosensors. Further, this review also covers the source of such marine biomaterials and their promising evolution in the fabrication of biosensors that are potent to be employed in the biomedical, environmental science and agricultural sciences domains. The use of such fabricated biosensors harness the system with excellent specificity, selectivity, biocompatibility, thermally stable and minimal cost advantages. This article is protected by copyright. All rights reserved.

Heparin-like anticoagulant polypeptides with tunable activity: Synthesis, characterization, anticoagulative properties and clot solubilities in vitro

Due to the uncontrollable anticoagulant activity and limited source, Heparin, which is commonly used in clinical anticoagulation therapies, faces the risk of spontaneous bleeding and thrombocytopenia. Herein, a series of anionic poly(amino acid) s poly (l-Serine-ran-L-Glutamic acid-ran-L-Cysteine-SO₃) (PSEC-SO₃) were prepared by the controlled Ring Opening Polymerization (ROP) of N-Carboxyanhydrides (NCAs). The anticoagulant activities of PSEC-SO₃ can be regulated by simply adjusting the feeding ratio of monomers. In vitro tests show that these polypeptides can effectively prolong the Activated Partical Thromboplastin Time (APTT) and inhibit Factor IIa and Factor Xa, but has no significant effect on Prothrombin Time (PT) and Thrombin Time (TT), which indicates that PSEC-SO₃ mainly act on the intrinsic pathway. In summary, the activity-tunable heparin-like polypeptides are expected to have good application prospects in the anticoagulant field.

Applications of chitosan and chitosan based metallic nanoparticles in agrosciences-A review

The second most abundant biological macromolecule, next to cellulose is Chitosan. It is a versatile naturally occurring hydrophilic polysaccharide, derived as a deacetylated form of chitin. Due to its biocompatibility, biodegradability and antimicrobial activity, it has become a significant area of research towards drug delivery system, plant growth promotion, anti-pathogenic potentiality, seed priming and in plant defense mechanism. Various synthetic strategies have been established in recent years that couples different metals with chitosan nanoparticles. Metals like silver, copper, zinc, iron and nickel are highly compatible to form chitosan metallic nanoparticles and are proved to be non-toxic to the agricultural plant system. This review highlights the mode of action of nanochitosan on Gram-positive and Gram-negative bacteria in a distinguished manner as well as its action on fungi. A prime focus has been given on the skeletal framework of the metallic nanochitosan particles. Our study also projects the antimicrobial mechanism of chitosan based on its physiochemical properties, environmental factors and the type of organism on which it acts. Moreover, the mechanism for stimulation of plant immunity by metallic nanochitosan has also been reviewed. Our study relies on the conclusion that chitosan metallic nanoparticles showed enhanced anti-pathogenic and plant growth promoting activity in comparison to bulk chitosan.

Construction of Kevlar nanofiber/graphene oxide composite beads as safe, self-anticoagulant, and highly efficient hemoperfusion adsorbents

Recently emerged hemoperfusion absorbents, e.g. ion-exchange resin, activated carbon, and other porous materials, provide numerous novel possibilities to cure chronic liver failure (CLF) and renal failure (CRF). However, the limited adsorption performance and unsatisfactory blood compatibility significantly impede the development of the absorbents. Hence, designing safe and self-anticoagulant hemoperfusion absorbents with robust toxin clearance remains a considerable challenge. Here, brand new Kevlar-based composite gel beads for hemoperfusion are prepared by interface assembly based on π-π interaction. First, Kevlar nanofiber-graphene oxide (K-GO) beads are produced by liquid-liquid phase separation. Then, sodium p-styrenesulfonate (SS) is adsorbed onto the K-GO interface by π-π interaction and initiated to achieve the composite gel (K-GO/PSS) beads with an interfacial crosslinked structure. Such composite gel beads possess superior mechanical strength and self-anticoagulation capability, owing to the dual-network structure and heparin-mimicking gel structure, respectively. Furthermore, the K-GO/PSS beads show robust adsorption capacities for different kinds of toxins due to their strong charge and π-π interactions. A simulated hemoperfusion experiment in vitro demonstrates that the concentrations of the toxins in the blood can be restored to normal values within 30 minutes. In general, we envision that such composite gel beads will provide new strategies for future clinical CLF and CRF treatments.

Paper based immunosensing of ovarian cancer tumor protein CA 125 using novel nano-ink: A new platform for efficient diagnosis of cancer and biomedical analysis using microfluidic paper-based analytical devices (μPAD)

Ovarian cancer is the first and most important cause of malignancy death in women. Mucin 16 or MUC16 protein also known as carcinoma antigen 125 (CA 125) is the most commonly used glycoprotein for early stage diagnosis of ovarian cancer. In this work, a novel paper-based bio-device through hand writing of Ag/RGO (silver nanoparticles/reduced graphene oxide) nano-ink on the flexible paper substrate using pen-on-paper technology was developed. The prepared interface was used to the recognition of CA 125 protein in human biofluid. For this purpose, Ag/rGO nano-ink was synthesized by deposition of Ag nanoparticles onto graphene oxide sheets and the reduction of graphene oxide to rGO simultaneously. Conductivity and resistance of conductive lines were studied after drawing on photographic paper. Subsequently, to prepare a new and unique immuno-device, paper electrode modified by cysteamine caped gold nanoparticles (CysA/Au NPs) using electrochemical techniques. CysA is bonded by sulfur atoms with Au (CysA/Au NPs), and from the amine group with hydroxyl and carboxyl groups of Ag/RGO nano-ink deposited on the surface of paper-based electrodes (CysA/Au NPs/Ag-rGO). Then, anti-CA 125 antibody was immobilized on the electrode surface through Au NPs and CA 125 positively charged amine groups interaction. Atomic force microscopy, Transmission electron microscopy, Field emission scanning electron microscopy, and dynamic light scattering, were performed to identify the engineered immunosensor. Using chronoamperometry technique and under the optimized conditions, the low limit of quantitation (LLOQ) for the proposed immunoassay was recorded as 0.78 U/ml, which this evaluation was performed at highly linear range of 0.78-400 U/ml. The high sensitivity of the electrochemical immunosensor device is indicative of the ability of this immuno-device to detect early stages ovarian cancer.

A hollow-nanosphere-based microfluidic biosensor for biomonitoring of cardiac troponin I

Cardiovascular diseases (CVDs) are the leading causes of death worldwide.

Sensitive and selective non-enzymatic detection of glucose by monodispersed NiO @ S-doped hollow carbon sphere hybrid nanostructures

Development of selective, sensitive and non-enzymatic sensor for glucose determination is highly important for the diagnosis and management of diabetes. Herein, we have reported the novel ultra sensitive and non-enzymatic sensor development by in-situ wraped NiO nanostructures (∼10-15 nm) on the sulfur-doped hollow carbon nanospheres (SDHCNSs) through hydrothermal-assisted process. The structural and morphological properties of the nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The prepared NiO@SDHCNSs was directly used as an electrochemical sensor for glucose determination, and its performance was evaluated by cyclic voltammetry and amperometric techniques. The fabricated non-enzymatic biosensor was exhibited remarkably good sensitivity (1697 μA mM^-1cm^-2), low detection limit (LOD) (52 nM), a wide linear range (up to 13 mM) of glucose with desirable selectivity, stability and reproducibility. Further, the constructed sensor has demonstrated an excellent anti-interference property in the presence of common interferences such as dopamine (DA), uric acid (UA) and ascorbic acid (AA). Most interestingly, the fabricated electrode is applicable for the practical analysis of glucose in the real blood serum and urine samples. The excellent electrochemical performances of NiO@SDHCNSs towards the oxidation of glucose are attributed to the increased electron transfer passage through unique hollow spherical morphology with increased redox couple of Ni(OH)₂/NiOOH derived from NiO. Thus, the improved electrochemical performances of NiO@SDHCNSs can be adopted as a potential electrode for the real sample analysis.

Ultrasensitive immunoassay of carcinoma antigen 125 in untreated human plasma samples using gold nanoparticles with flower like morphology: A new platform in early stage diagnosis of ovarian cancer and efficient management

Ovarian cancer, as one of the most life-threatening malignancies among women worldwide, is usually diagnosed at the late stage despite up regulation of molecular markers such as carcinoma antigen 125 (CA 125) at the early stages of the malignancy. CA 125 is the only tumor marker recommended for clinical use in the diagnosis and management of ovarian cancer. The potential role of CA-125 for the early detection of ovarian cancer is controversial and has not yet been adopted for widespread screening efforts in asymptomatic women. Therefore, early detection of CA 125 in human biofluids is highly demanded. In the present study, a novel method was proposed for the fabrication of electrochemical immunosensor based reduced graphene oxide (RGO). Cysteamine capped gold nanoparticle (Cys-AuNPs) were deposited over the surface of ERGO probe using electrophoretic deposition method. These Cys-AuNPs/ERGO probes provide the favorable sites to attach the monoclonal antibody specific to CA 125 antigen. Cyclic voltammetry (CV), and square wave voltammetry (SWV) were applied for the electrochemical recognition of the biolayer. The represented signals demonstrates excellent figure of merits and good capability of the engineered immunosensor towards sensitive detection of CA 125. Quantitative measurements of CA 125 in human plasma samples have been demonstrated, showing the potential of the practical application of this novel immunosensor for the analysis of this biomarker in blood serum samples. This immunosensor has the ability of direct electron transfer as compared to earlier reported electrochemical immunosensors based electrochemical methods. Further, this immunosensor provides a very suitable and convenient alternative to replace the expensive commercially available methods such as immunohistochemistry. The following regression equation between the electrochemical current response and the CA 125 concentration range from 0.1 to 400 U/mL was found. The low limit of quantification for this immunosensor was 0.1 U/mL. To the best of our knowledge, this is the first reported on the direct immobilization of antibody on the surface of Cys-AuNPs/ERGO for fabrication of immunosensors.

Amino acid functionalized ZrO2 nanoparticles decorated reduced graphene oxide based immunosensor

Here, a study is reported on a simple, one-step method for the synthesis of a zirconium dioxide–reduced graphene oxide (ZrO₂–RGO) nanocomposite and its functionalization with amino acid to develop an immunosensor for detection of ochratoxin A.