EDTA-Cu (II) chelating magnetic nanoparticles as a support for laccase immobilization

Nanomaterials for diabetes: diagnosis, detection and delivery

537 million people worldwide suffer from diabetes mellitus, a problem of glucose management that is related to a number of major health risks, including cardiovascular diseases. There is a need for new, efficient formulations of diabetic medications to address this condition and its related consequences because existing treatments have a number of drawbacks and limits. This encouraged the development of treatment plans to get around some of these restrictions, like low therapeutic drug bioavailability or patients' disobedience to existing therapies. Approaches based on nanotechnology have a lot of promise to enhance the treatment of diabetic patients. In order to manage blood glucose, this review article highlights recent developments and explores the potential applications of different materials (polymeric, ceramic, dendrimers, etc.) as nanocarriers for the delivery of insulin and other antidiabetic medications. Using an injectable and acid-degradable polymeric network produced by the electrostatic interaction of oppositely charged dextran nanoparticles loaded with insulin and glucose-specific enzymes, we reviewed a glucose-mediated release approach for the self-regulated delivery of insulin, in which, after a degradable nano-network was subcutaneously injected into type 1 diabetic mice,in vivoexperiments confirmed that these formulations improved glucose management. In addition, a discussion of silica-based nanocarriers, their potential for treating diabetes and controlling blood glucose levels, and an explanation of the role of dendrimers in diabetes treatment have been covered. This is done by utilizing the properties of silica nanoparticles, such as their tuneable particle and pore size, surface chemistry, and biocompatibility. The article summarized the significance of nanomaterials and their uses in the diagnosis and treatment of diabetes overall, illuminating the field's potential and outlining its prospects for the future.

Polycarboxylate functionalized magnetic nanoparticles Fe3O4@SiO2@CS-COOH: Preparation, characterization, and immobilization of bovine serum albumin

Magnetic nanoparticles with increasing superparamagnetism and magnetic targeting have found widespread application in fields such as food and medicine. In this study, polycarboxylated magnetic nanoparticles (Fe3O4@SiO2@CS-COOH) were prepared by surface functionalizing iron tetraoxide (Fe3O4) nanoparticles with ethylenediaminetetraacetic acid (EDTA) as a modifier. The appropriate degree of functionalization modification was obtained by adjusting the EDTA concentration and the ratio of cross-linking agents. The prepared magnetic nanoparticles were analyzed with structural and property characterization. The results showed that the Fe3O4@SiO2@CS-COOH magnetic nanoparticles prepared with 4 % EDTA and cross-linking agents at a molar ratio of 3:4 were uniform in particle size, with an average size of roughly 7 nm, and possessed an abundant carboxylate content (310.8064 μmol/g) and a high magnetization intensity (35.05 emu/g). As a model protein, bovine serum albumin (BSA) was immobilized on the surface of magnetic particles. The largest amount of immobilized protein was 500.4376 mg BSA/g at pH 4.0 and no extra salt ions. According to molecular docking simulations, its immobilization was due to the interaction of amino and carboxyl groups at the Fe3O4@SiO2@CS-COOH/BSA interface. Fe3O4@SiO2@CS-COOH possesses a large number of carboxyl groups, strong protein immobilization, and magnetic responsiveness, which may have potential applications in biomedical and food fields.

EDTA-functionalized silica nanoparticles as a conditioning agent for dentin bonding using etch-and-rinse technique

OBJECTIVE

This study investigated the possibility of using ethylenediaminetetraacetic acid functionalized silica nanoparticles (EDTA-SiO₂) as a dentin-conditioning agent using etch-and-rinse technique to promote the durability of dentin bonding.

METHODS

The SiO₂-EDTA were synthesized by N- [(3- trimethoxysilyl) propyl] ethylenediamine triacetic acid (EDTA-TMS) and SiO₂ (50 nm), then characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The capacity of SiO₂-EDTA to chelate calcium ions from dentin was examined by inductively coupled plasma-optic emission spectrometry (ICP-OES). The dentin surfaces conditioned with SiO₂-EDTA were detected by field emission scanning electron microscopy (SEM), TEM and microhardness testing. For dentin bonding, dentin surfaces were adopted wet- or dry-bonding technique and bonded with adhesive (Adper^TM Single Bond2) and applied composite resin (Filtek Z350) on them. The durability of dentin bonding was evaluated by mircotensile bond strength test, in-situ zymography and nanoleakage testing.

RESULTS

FTIR, TGA and XPS results showed that SiO₂-EDTA contained N element and carboxyl groups. SEM, TEM and microhardness results indicated that SiO₂-EDTA group created extrafibrillar demineralization and retained more intrafibrillar minerals within dentin surface. In the dentin bonding experiment, SiO₂-EDTA group achieved acceptable bond strength, and reduced the activity of matrix metalloproteinase and nanoleakage along bonding interface.

CONCLUSION

It was possible to generate a feasible dentin conditioning agent (SiO₂-EDTA), which could create dentin extrafibrillar demineralization and improve dentin bond durability.

CLINICAL SIGNIFICANCE

This study introduces a new dentin conditioning scheme based on SiO₂-EDTA to create extrafibrillar demineralization for dentin bonding. This strategy has the potential to be used in clinic to promote the life of restoration bonding.

Applications and immobilization strategies of the copper-centred laccase enzyme; a review

Laccase is a multi-copper enzyme widely expressed in fungi, higher plants, and bacteria which facilitates the direct reduction of molecular oxygen to water (without hydrogen peroxide production) accompanied by the oxidation of an electron donor. Laccase has attracted attention in biotechnological applications due to its non-specificity and use of molecular oxygen as secondary substrate. This review discusses different applications of laccase in various sectors of food, paper and pulp, waste water treatment, pharmaceuticals, sensors, and fuel cells. Despite the many advantages of laccase, challenges such as high cost due to its non-reusability, instability in harsh environmental conditions, and proteolysis are often encountered in its application. One of the approaches used to minimize these challenges is immobilization. The various methods used to immobilize laccase and the different supports used are further extensively discussed in this review.

Silica-Based Nanomaterials for Diabetes Mellitus Treatment

Diabetes mellitus, a chronic metabolic disease with an alarming global prevalence, is associated with several serious health threats, including cardiovascular diseases. Current diabetes treatments have several limitations and disadvantages, creating the need for new effective formulations to combat this disease and its associated complications. This motivated the development of therapeutic strategies to overcome some of these limitations, such as low therapeutic drug bioavailability or poor compliance of patients with current therapeutic methodologies. Taking advantage of silica nanoparticle characteristics such as tuneable particle and pore size, surface chemistry and biocompatibility, silica-based nanocarriers have been developed with the potential to treat diabetes and regulate blood glucose concentration. This review discusses the main topics in the field, such as oral administration of insulin, glucose-responsive devices and innovative administration routes.

Recent progress in the applications of silica-based nanoparticles

Functionalized silica nanoparticles (SiO2 NPs) have attracted great attention due to their promising distinctive, versatile, and privileged physiochemical characteristics. These enhanced properties make this type of functionalized nanoparticles particularly appropriate for different applications. A lack of reviews that summarizes the fabrications of such nanomaterials and their different applications in the same work has been observed in the literature. Therefore, in this work, we will discuss the recent signs of progress in the fabrication of functionalized silica nanoparticles and their attractive applications that have been extensively highlighted (advanced catalysis, drug-delivery, biomedical applications, environmental remediation applications, and wastewater treatment). These applications have been selected for demonstrating the role of the surface modification step on the various properties of the silica surface. In addition, the current challenges in the applications of functionalized silica nanoparticles and corresponding strategies to discuss these issues and future perspectives for additional improvement have been addressed.

Surface-coated magnetic nanostructured materials for robust bio-catalysis and biomedical applications-A review

BACKGROUND

Enzymes based bio-catalysis has wide range of applications in various chemical and biological processes. Thus, the process of enzymes immobilization on suitable support to obtain highly active and stable bio-catalysts has great potential in industrial applications. Particularly, surface-modified magnetic nanomaterials have garnered a special interest as versatile platforms for biomolecules/enzyme immobilization.

AIM OF REVIEW

This review spotlights recent progress in the immobilization of various enzymes onto surface-coated multifunctional magnetic nanostructured materials and their derived nano-constructs for multiple applications. Conclusive remarks, technical challenges, and insightful opinions on this field of research which are helpful to expand the application prospects of these materials are also given with suitable examples.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Nanostructured materials, including surface-coated magnetic nanoparticles have recently gained immense significance as suitable support materials for enzyme immobilization, due to their large surface area, unique functionalities, and high chemical and mechanical stability. Besides, magnetic nanoparticles are less expensive and offers great potential in industrial applications due to their easy recovery and separation form their enzyme conjugates with an external magnetic field. Magnetic nanoparticles based biocatalytic systems offer a wide-working temperature, pH range, increased storage and thermal stabilities. So far, several studies have documented the application of a variety of surface modification and functionalization techniques to circumvent the aggregation and oxidation of magnetic nanoparticles. Surface engineering of magnetic nanoparticles (MNPs) helps to improve the dispersion stability, enhance mechanical and physicochemical properties, upgrade the surface activity and also increases enzyme immobilization capabilities and biocompatibility of the materials. However, several challenges still need to be addressed, such as controlled synthesis of MNPs and clinical aspects of these materials require consistent research from multidisciplinary scientists to realize its practical applications.

Facile preparation of amorphous cobalt phosphate as inorganic carrier for direct separation and immobilization of his-tagged β-glucosidase from cell lysate

The present work was aimed to develop a facile method to fabricate solid support for the separation and immobilization of his-tagged enzymes directly from cell lysate without pre-purification of the enzymes.

Enzymatic treatment of phenolic pollutants by a small laccase immobilized on APTES-functionalised magnetic nanoparticles

In this study, we have successfully synthesized magnetic nanoparticles (MNPs), functionalised them by silanization and used them for the covalent immobilization of a recombinant small laccase (rSLAC) from Streptomyces coelicolor. The immobilized recombinant laccase (MNP-rSLAC) was subsequently used for the treatment of phenol, 4-chlorophenol (4-CP) and 4-fluorophenol (4-FP). The enzyme completely degraded 80 µg/mL of the selected phenolic compounds within 2 h in the presence of a natural mediator, acetosyringone. The MNP-rSLAC retained > 73% of initial activity (2,6-dimethoxyphenol as substrate) after 10 catalytic cycles and could be easily recovered from the reaction mixture by the application of magnetic field. Furthermore, immobilised rSLAC exhibited better storage stability than its free counterpart. The Michaelis constant (K_m) value for the immobilised rSLAC was higher than free rSLAC, however the maximum velocity (V_max) of the immobilised SLAC was similar to that of the free rSLAC. Growth inhibition studies using Escherichia coli showed that rSLAC-mediated treatment of phenolic compounds reduced the toxicity of phenol, 4-CP and 4-FP by 90, 60 and 55%, respectively. Interestingly, the presence of selected metal ions (Co²⁺, Cu²⁺, Mn²⁺) greatly enhanced the catalytic activity of rSLAC and MNP-rSLAC. This study indicates that immobilized small laccase (MNP-rSLAC) has potential for treating wastewater contaminated with phenolic compounds.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02854-0.

Immobilization of formate dehydrogenase in metal organic frameworks for enhanced conversion of carbon dioxide to formate

Hydrogenation of carbon dioxide (CO₂) to formic acid by the enzyme formate dehydrogenase (FDH) is a promising technology for reducing CO₂ concentrations in an environmentally friendly manner. However, the easy separation of FDH with enhanced stability and reusability is essential to the practical and economical implementation of the process. To achieve this, the enzyme must be used in an immobilized form. However, conventional immobilization by physical adsorption is prone to leaching, resulting in low stability. Although other immobilization methods (such as chemical adsorption) enhance stability, they generally result in low activity. In addition, mass transfer limitations are a major problem with most conventional immobilized enzymes. In this review paper, the effectiveness of metal organic frameworks (MOFs) is assessed as a promising alternative support for FDH immobilization. Kinetic mechanisms and stability of wild FDH from various sources were assessed and compared to those of cloned and genetically modified FDH. Various techniques for the synthesis of MOFs and different immobilization strategies are presented, with special emphasis on in situ and post synthetic immobilization of FDH in MOFs for CO₂ hydrogenation.

Recent Strategies and Applications for l-Asparaginase Confinement

l-asparaginase (ASNase, EC 3.5.1.1) is an aminohydrolase enzyme with important uses in the therapeutic/pharmaceutical and food industries. Its main applications are as an anticancer drug, mostly for acute lymphoblastic leukaemia (ALL) treatment, and in acrylamide reduction when starch-rich foods are cooked at temperatures above 100 °C. Its use as a biosensor for asparagine in both industries has also been reported. However, there are certain challenges associated with ASNase applications. Depending on the ASNase source, the major challenges of its pharmaceutical application are the hypersensitivity reactions that it causes in ALL patients and its short half-life and fast plasma clearance in the blood system by native proteases. In addition, ASNase is generally unstable and it is a thermolabile enzyme, which also hinders its application in the food sector. These drawbacks have been overcome by the ASNase confinement in different (nano)materials through distinct techniques, such as physical adsorption, covalent attachment and entrapment. Overall, this review describes the most recent strategies reported for ASNase confinement in numerous (nano)materials, highlighting its improved properties, especially specificity, half-life enhancement and thermal and operational stability improvement, allowing its reuse, increased proteolysis resistance and immunogenicity elimination. The most recent applications of confined ASNase in nanomaterials are reviewed for the first time, simultaneously providing prospects in the described fields of application.

Construction of magnetic nanoflower biocatalytic system with enhanced enzymatic performance by biomineralization and its application for bisphenol A removal

This study first reported a magnetic nanoflower biocatalyst of the core-shell magnetic composite microspheres with a hierarchical flower-like surface structure, which was consist of the organic component (horseradish peroxidase, HRP) and the inorganic component (Fe₃O₄@PMG-IDA-Cu²⁺) through self-assembly in the phosphate buffered saline (PBS) solution. The structure, pattern and crystallization of the magnetic nanoflowers were confirmed through a series of characterization. The optimized results of the magnetic nanoflowers formation conditions demonstrated that their hierarchical structure could effectively enhance the enzyme activity. The magnetic nanoflowers exhibited enhanced durability, stability and reusability through the study of enzymatic properties. The magnetic nanoflowers were applied to remove the bisphenol A (BPA) from water and the removal efficiency reached about 92.1%, meanwhile the enzymatic activity of the magnetic nanoflowers was achieved 183% enhancement in comparison with free HRP. In addition, the magnetic nanoflowers showed outstanding reusability and reproducibility, which would have potential application in biocatalysis.

Biodegradation of Cibacron Blue 3GA by insolubilized laccase and identification of enzymatic byproduct using MALDI-ToF-MS: Toxicity assessment studies by Daphnia magna and Chlorella vulgaris

The presented paper describes a detailed study on the use of immobilized laccase for effective degradation of Cibacron Blue 3GA dye. The amount of laccase loading on the cyclic carbonate groups containing poly(hydroxyethyl methacrylate-co-vinylene carbonate), p(HEMA-co-VC), microbeads was 27.8 mg g^-1, and the retained immobilized enzyme activity was 73% compared to free enzyme. The toxicity of the dye and its byproducts were studied using Daphnia magna as test organism. The micro-algal growth inhibition was also studied using a green micro algae "Chlorella vulgaris". MALDI-ToF-MS was used to verify dye degradation byproducts. After 60 min of incubation period, Cibacron Blue 3GA (CB3GA) and its byproducts disappeared from the medium. After 60-min enzymatic treatment, the non-toxic nature of medium was confirmed by toxicity studies. On the other hand, the initial byproducts of the dye seemed to be more toxic than the later formed dye products. It should be noted that the information obtained from this study can be beneficial for understanding the initial degradation byproducts toxicities of the enzymatically treated dyes to provide information about environmental protection.

Electrospray ionization photoelectron spectroscopy of cryogenic [EDTA·M(ii)]2− complexes (M = Ca, V–Zn): electronic structures and intrinsic redox properties

A systematic photoelectron spectroscopy and theoretical study of divalent transition metal EDTA complexes illustrating the intrinsic correlations of redox properties in the gas and solution phases.

Bacterial laccases: promising biological green tools for industrial applications

Multicopper oxidases (MCOs) are a pervasive family of enzymes that oxidize a wide range of phenolic and nonphenolic aromatic substrates, concomitantly with the reduction of dioxygen to water. MCOs are usually divided into two functional classes: metalloxidases and laccases. Given their broad substrate specificity and eco-friendliness (molecular oxygen from air as is used as the final electron acceptor and they only release water as byproduct), laccases are regarded as promising biological green tools for an array of applications. Among these laccases, those of bacterial origin have attracted research attention because of their notable advantages, including broad substrate spectrum, wide pH range, high thermostability, and tolerance to alkaline environments. This review aims to summarize the significant research efforts on the properties, mechanisms and structures, laccase-mediator systems, genetic engineering, immobilization, and biotechnological applications of the bacteria-source laccases and laccase-like enzymes, which principally include Bacillus laccases, actinomycetic laccases and some other species of bacterial laccases. In addition, these enzymes may offer tremendous potential for environmental and industrial applications.

Magnetic nanoparticles: a versatile carrier for enzymes in bio-processing sectors

Many industrial processes experience the advantages of enzymes which evolved the demand for enzymatic technologies. The enzyme immobilisation technology using different carriers has trustworthy applications in industrial biotechnology as these techniques encompass varied advantages such as enhanced stability, activity along with reusability. Immobilisation onto nanomaterial is highly favourable as it includes almost all aspects of science. Among the various techniques of immobilisation, the uses of nanoparticles are remarkably well perceived as these possess high-specific surface area leading to high enzyme loadings. The magnetic nanoparticles (MNPs) are burgeoning in the field of immobilisation as it possess some of the unique properties such as high surface area to volume ratio, uniform particle size, biocompatibility and particularly the recovery of enzymes with the application of an external magnetic field. Immobilisation of industrially important enzymes onto nanoparticles offers overall combined benefits. In this review, the authors here focus on the current scenario in synthesis and functionalisation of MNPs which makes it more compatible for the enzyme immobilisation and its application in the biotechnological industries.

Immobilization of peroxidase on polypyrrole-cellulose-graphene oxide nanocomposite via non-covalent interactions for the degradation of Reactive Blue 4 dye

In the present study novel polypyrrole-cellulose-graphene oxide nanocomposite (PCeGONC) was employed for the immobilization of ginger peroxidase (GP) via simple adsorption mechanism. Immobilization of enzyme on the obtained support resulted in enhancement of the enzyme activity. The recovery of activity was 128% of the initial activity. Consequently, in 3 h stirred batch treatment, PCeGONC bound GP exhibited higher decolorization efficiency (99%) for Reactive Blue 4 (RB 4) dye as compared to free GP (88%). The immobilized GP exhibited higher operational stability and retained approximately 72% of its initial activity even after ten sequential cycles of dye decolorization in batch process. The kinetic characterization of PCeGONC bound GP revealed slightly lower K_m and 3.3 times higher V_max compared to free GP. Degraded products were identified on the basis of GC-MS analysis and degradation pathway was proposed accordingly which confirms enzymatic breakdown of RB 4 into low molecular weight compounds. Genotoxic assessment of GP treated RB 4 revealed significant reduction of its genotoxic potential. In-silico analysis identified that binding site of PCeGONC on enzyme is distinct and lies far away from the active site of the enzyme. Furthermore, it also revealed higher affinity of 1-hydroxybenzotriazole (a redox mediator) and RB 4 for PCeGONC bound enzyme as compared to the free enzyme. This is in consensus with the observed decrease in K_m of the immobilized GP.

One-pot synthesis of microporous nanoscale metal organic frameworks conjugated with laccase as a promising biocatalyst

Fabrication of amine-functionalized NMOFs followed by immobilization of laccase, a multicopper oxidase,viaa one-pot synthetic procedure.