Fluorescence assay for the determination of glutathione based on a ring-fused 2-pyridone derivative in dietary supplements.

Herein, a novel fluorescent method for the determination of GSH levels in aqueous solutions involving the utilization of citric acid as a derivatization reagent was developed. Therefore, the crucial parameters of the derivatization process were established from what has resulted in the development of a sensitive, reproducible, and accurate GSH assay. The method was validated, and its applicability in the characterization of the GSH concentration in dietary supplements concerning the selectivity in the determination of GSH over GSSG was both confirmed. The chemical structure of the new fluorophore 3-[(carboxymethyl)carbamoyl]-5-oxo-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyridine-7-carboxylic acid - CTPC was elucidated using detailed NMR: one-dimensional (1H, 13C), as well as two-dimensional NMR spectra (1H-1H COSY, 1H-13C HSQC, 1H-13C HMBC, 1H-15N HSQC, 1H-15N HMBC) experiments. Besides, the essential optical, biological and antioxidative properties of CTPC were investigated.

Cyclodextrin-modified poly(octamethylene citrate) polymers towards enhanced sorption properties.

Herein, we describe the synthesis of poly(1,8-octamethylene citrate) materials modified in the bulk with 2-hydroxypropyl-ß-cyclodextrin (cPOCCD), biodegradable elastomers with intrinsic sorption properties for drug delivery. The chemical structure, physicochemical properties, in vitro drug loading and release profiles of cPOCCD were investigated. Thus, cPOCCD polyesters absorb the studied drugs more effective and release them for a longer period of time than poly(1,8-octamethylene citrate) materials not containing cyclodextrins.

Coumarin-Modified CQDs for Biomedical Applications-Two-Step Synthesis and Characterization.

Waste biomass such as lignin constitutes a great raw material for eco-friendly carbon quantum dots (CQDs) synthesis, which find numerous applications in various fields of industry and medicine. Carbon nanodots, due to their unique luminescent properties as well as water-solubility and biocompatibility, are superior to traditional organic dyes. Thus, obtainment of CQDs with advanced properties can contribute to modern diagnosis and cell visualization method development. In this article, a new type of coumarin-modified CQD was obtained via a hybrid, two-step pathway consisting of hydrothermal carbonization and microwave-assisted surface modification with coumarin-3-carboxylic acid and 7-(Diethylamino) coumarin-3-carboxylate. The ready products were characterized over their chemical structure and morphology. The nanomaterials were confirmed to have superior fluorescence characteristics and quantum yield up to 18.40%. They also possessed the ability of biomolecules and ion detection due to the fluorescence quenching phenomena. Their lack of cytotoxicity to L929 mouse fibroblasts was confirmed by XTT assay. Moreover, the CQDs were proven over their applicability in real-time bioimaging. Obtained results clearly demonstrated that proposed surface-modified carbon quantum dots may become a powerful tool applicable in nanomedicine and pharmacy.

Smart, Tunable CQDs with Antioxidant Properties for Biomedical Applications-Ecofriendly Synthesis and Characterization.

Carbon quantum dots (CQDs) are nanoobjects of a size below 10 nm. Due to their favorable features, such as tunable luminescence, unique optical properties, water solubility, and lack of cytotoxicity, they are willingly applied in biomedicine. They can be obtained via bottom-up and top-down methods. However, to increase their quantum yield they must undergo post-processing. The aim of the following research was to obtain a new type of CQDs modified with a rhodamine b derivative to enhance their fluorescence performance without biocompability deterioration. For their preparation glucose was used as a precursor and four different carbonizing agents which affected semi- and final products luminescence properties. The ready nanomaterials were investigated over their chemical structure by FTIR and NMR, whereas morphology was investigated by the TEM method. Their optical properties were determined by UV-VIS spectroscopy. Fluorescence behavior, photo- and pH-stability, as well as solvatochromism showed their applicability in various biomedical applications due to the controlled properties. The samples exhibited excellent antioxidant activity and lack of cytotoxicity on L929 mouse fibroblasts. The results showed that proposed strategy enables preparation of the superior nanomaterials with outstanding luminescence properties such as quantum yield up to 17% which can be successfully applied in cell labelling, bioimaging, and theranostics.

Chitosan-Based Bioactive Hemostatic Agents with Antibacterial Properties-Synthesis and Characterization.

Massive blood loss is responsible for numerous causes of death. Hemorrhage may occur on the battlefield, at home or during surgery. Commercially available biomaterials may be insufficient to deal with excessive bleeding. Therefore novel, highly efficient hemostatic agents must be developed. The aim of the following research was to obtain a new type of biocompatible chitosan-based hemostatic agents with increased hemostatic properties. The biomaterials were obtained in a quick and efficient manner under microwave radiation using l-aspartic and l-glutamic acid as crosslinking agents with no use of acetic acid. Ready products were investigated over their chemical structure by FT-IR method which confirmed a crosslinking process through the formation of amide bonds. Their high porosity above 90% and low density (below 0.08 g/cm3) were confirmed. The aerogels were also studied over their water vapor permeability and antioxidant activity. Prepared biomaterials were biodegradable in the presence of human lysozyme. All of the samples had excellent hemostatic properties in contact with human blood due to the platelet activation confirmed by blood clotting tests. The SEM microphotographs showed the adherence of blood cells to the biomaterials' surface. Moreover, they were biocompatible with human dermal fibroblasts (HDFs). The biomaterials also had superior antibacterial properties against both Staphylococcus aureus and Escherichia coli. The obtained results showed that proposed chitosan-based hemostatic agents have great potential as a hemostatic product and may be applied under sterile, as well as contaminated conditions, by both medicals and individuals.

The Effect of Rapeseed Oil Biopolyols and Cellulose Biofillers on Selected Properties of Viscoelastic Polyurethane Foams.

This paper presents the results of research on polyurethane viscoelastic foams (PUVFs) modified with biomaterials. This investigation looked at the effect of the biomaterials on the foaming processes, as well as the acoustical and selected physical-mechanical properties of the foams. Various types of rapeseed oil biopolyols and microcellulose were used to modify the materials. The analysis of properties covered a reference biopolyol-free sample and materials containing 10 wt.%, 20 wt.%, and 30 wt.% of different types of biopolyols in the mixture of polyol components. The biopolyols differed in terms of functionality and hydroxyl value (OHv). Next, a selected formulation was modified with various microcellulose biofillers in the amount of 0.5-2 wt.%. The PUVFs, with apparent densities of more than 210 kg/m3 and open-cell structures (more than 85% of open cells), showed a slow recovery to their original shape after deformation when the pressure force was removed. They were also characterized by a tensile strength in the range of 156-264 kPa, elongation at break of 310-510%, hardness of 8.1-23.1 kPa, and a high comfort factor of 3.1-7.1. The introduction of biopolyols into the polyurethane system resulted in changes in sound intensity levels of up to 31.45%, while the addition of fillers resulted in changes in sound intensity levels of up to 13.81%.

Commercial-Scale Modification of NdFeB Magnets under Laser-Assisted Conditions.

Rare Earth elements (REE) such as NdFeB are commonly used to produce permanent magnets. Thanks to their superior properties, these materials are highly desirable for green energy applications such as wind power generators or electric cars. Currently, REEs are critical for the ongoing development of eco-friendly solutions in different industrial branches. The emerging issue of REE depletion has led to a need for new methods to enable the life cycle elongation, resistance to wear, and external factors improvement of NdFeB magnets. This can be achieved by advanced, nanostructured coating formation of magnet surfaces to increase their functionality and protect from humidity, pressure, temperature, and other factors. The aim of the following research was to develop a new, scalable strategy for the modification of NdFeB magnets using laser-assisted technique, also known as Laser cladding. For this purpose, four different micropowders were used to modify commercial NdFeB samples. The products were investigated for their morphology, structure, chemical composition, and crystallography. Moreover, magnetic flux density was evaluated. Our results showed that laser cladding constitutes a promising strategy for REE-based permanent magnets modification and regeneration and may help to improve durability and resistance of NdFeB components.

Environment-Friendly Preparation and Characterization of Multilayered Conductive PVP/Col/CS Composite Doped with Nanoparticles as Potential Nerve Guide Conduits.

Tissue engineering constitutes the most promising method of severe peripheral nerve injuries treatment and is considered as an alternative to autografts. To provide appropriate conditions during recovery special biomaterials called nerve guide conduits are required. An ideal candidate for this purpose should not only be biocompatible and protect newly forming tissue but also promote the recovery process. In this article a novel, multilayered biomaterial based on polyvinylpyrrolidone, collagen and chitosan of gradient structure modified with conductive nanoparticles is presented. Products were obtained by the combination of electrospinning and electrospraying techniques. Nerve guide conduits were subjected to FT-IR analysis, morphology and elemental composition study using SEM/EDS as well as biodegradation. Furthermore, their effect on 1321N1 human cell line was investigated by long-term cell culture. Lack of cytotoxicity was confirmed by XTT assay and morphology study. Obtained results confirmed a high potential of newly developed biomaterials in the field of nerve tissue regeneration with a special focus on injured nerves recovery.

Evaluation of Physiochemical and Biological Properties of Biofunctionalized Mg-Based Implants Obtained via Large-Scale PEO Process for Dentistry Applications.

An increasing number of tooth replacement procedures ending with implant failure generates a great need for the delivery of novel biomedical solutions with appropriate mechanical characteristics that would mimic natural tissue and undergo biodegradation. This phenomenon constitutes a significant difficulty for scientists, since currently applied biomaterials dedicated for this purpose are based on stainless steel, Ti, and Ti and CoCr alloys. One of the most promising raw materials is magnesium, which has been proven to promote bone regeneration and accelerate the tissue healing process. Nevertheless, its high reactivity with body fluid components is associated with fast and difficult-to-control biocorrosion, which strongly limits the application of Mg implants as medical devices. The achievement of appropriate functionality, both physiochemical and biological, to enable the commercial use of Mg biomaterials is possible only after their superficial modification. Therefore, the obtainment of uniform, reproducible coatings increasing resistance to the aqueous environment of the human body combined with a nanostructured surface that enhances implant-cell behaviors is an extremely important issue. Herein, we present a successful strategy for the modification of Mg implants via the PEO process, resulting in the obtainment of biomaterials with lower corrosion rates and superior biological properties, such as the promotion of extracellular matrix formation and a positive impact on the proliferation of MG-63 cells. The implants were investigated regarding their chemical composition using the FT-IR and XRD methods, which revealed that MgO layer formation, as well as the incorporation of electrolyte components such as fluorine and silica, were responsible for the increased microhardness of the samples. An extensive study of the biomaterials' morphology confirmed that successful surface modification led to a microporous structure suitable for the attachment and proliferation of cells. The three-layer nature of the newly-formed coatings, typical for PEO modification, was confirmed via cross-section analysis. A biocorrosion and biodegradation study proved that applied modification increased their resistance to body fluids. The cell culture study performed herein confirmed that the correct adjustment of modification parameters results in a lack of cytotoxicity of the magnesium implants, cell proliferation enhancement, and improvement in extracellular matrix formation.

Application of hydrogen peroxide encapsulated in silica xerogels to oxidation reactions.

Hydrogen peroxide was encapsulated into a silica xerogel matrix by the sol-gel technique. The composite was tested as an oxidizing agent both under conventional and microwave conditions in a few model reactions: Noyori's method of octanal and 2-octanol oxidation and cycloctene epoxidation in a 1,1,1-trifluoroethanol/Na2WO4 system. The results were compared with yields obtained for reactions with 30% H2O2 and urea-hydrogen peroxide (UHP) as oxidizing agents. It was found that the composite has activity similar to 30% H2O2 and has a several advantages over UHP such as the fact that silica and H2O are the only products of the composite decomposition or no contamination by urea or its derivatives occurs; the xerogel is easier to heated by microwave irradiation than UHP and could be used as both an oxidizing agent and as solid support for microwave assisted solvent-free oxidations.

Thiol-Ene Coupling of High Oleic Sunflower Oil towards Application in the Modification of Flexible Polyurethane Foams.

High oleic sunflower oil-based polyol was obtained by thiol-ene coupling and applied in the preparation of flexible polyurethane foams. The photochemically initiated thiol-ene click reaction was carried out under UV irradiation using 2-mercaptoethanol. Bio-based polyol with hydroxyl value of 201.4 mg KOH/g was used as 30 wt% substituent of petrochemical polyether polyol in the formulations of flexible foams. Both reference foams, as well as foams modified with bio-based polyol, were formulated to have various isocyanate indices (0.85, 0.95, 1.05). Flexible foams were compared in terms of their thermomechanical properties and analyzed using FT-IR and SEM microscopy. Modification with bio-based polyol resulted in foams with superior compression properties, higher support factor, and lower resilience than reference foams. TGA and FT-IR curves confirmed the presence of urethane/urea and ether linkages in the polyurethane matrix. Moreover, double glass transition temperature corresponding to soft and hard segments of polyurethane was observed by DSC proving the phase-separated morphology.

Development of Stimuli-Responsive Chitosan/ZnO NPs Transdermal Systems for Controlled Cannabidiol Delivery.

One of the most common neurological diseases is epilepsy, which not only negatively affects the quality of people's life but also may lead to life-threatening situations when its symptoms such as seizures cannot be controlled medically. A very serious problem to be overcame is the untreatable form of this disease, which cannot be cured by any currently available medicines. Cannabidiol, which is a natural product obtained from Cannabis Sativa, brings a new hope to people suffering from drug-resistant epilepsy. However, the hydrophobic character of this compound significantly lowers its clinical efficiency. One of the promising methods of this substance bioactivity increase is delivery through the skin tissue. In this article, a new type of advanced transdermal systems based on chitosan and ZnO nanoparticles (NPs) has been developed according to Sustained Development principles. The chemical modification of the biopolymer confirmed by FT-IR method resulted in the preparation of the material with great swelling abilities and appropriate water vapor permeability. Obtained nanoparticles were investigated over their crystalline structure and morphology and their positive impact on drug loading capacity and cannabidiol controlled release was proved. The novel biomaterials were confirmed to have conductive properties and not be cytotoxic to L929 mouse fibroblasts.

Advancements in structure-property correlation studies of cross-linked citric acid-based elastomers from the perspective of medical application.

Herein, a renewed prominence towards the synthesis of poly(alkylene citrate) (PAC) biomaterials and their detailed chemical, structural and mechanical characterization has been reported. Based on the modifications to the PAC synthesis protocol introduced in this study, the fabrication process was significantly streamlined, the reaction yields were increased, and the homogeneity of the final materials was found to be substantially improved. Comprehensive nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) studies of the fabricated prepolymers shed light on the mechanism of the PAC cross-linking process and supported the design of materials with enhanced biocompatibility. Therefore, the initial molar ratio of the reagents involved in the synthesis of PAC materials was found to be pivotal to both the biological and mechanical properties of the final products. Moreover, cell viability and proliferation assays revealed enhanced biocompatibility of the materials formulated with a molar ratio of diol over citric acid (3 : 2 mol/mol) in comparison to the most commonly described 1 : 1 analogue without affecting the possibility of further functionalization. Furthermore, this work creates a new paradigm for prospective studies on the properties of modified PAC materials and their application in medicine and tissue engineering.

Fungal Chitosan-Derived Biomaterials Modified with Kalanchoe pinnata as Potential Hemostatic Agents-Development and Characterization.

Massive blood loss is still a great challenge for modern medicine. To stop the hemorrhage during the surgery or after injury apart from suturing or electrocoagulation, the most efficient method of hemostasis restoration is the use of hemostatic agents. Although there are numerous products on the market, there is still a need for biomaterials that are capable of fast and efficient bleeding management without affecting wound closure or embolism. Chitosan is known for its hemostatic activity; however, its quite poor mechanical properties and heterogenous chemical composition still needs some improvements to become superior compared to biological adhesives. The following study deals with the preparation and evaluation of chitosan-derived natural biomaterials containing Kalanchoe pinnata extract with the potential application as a blood-clotting agent. The materials were obtained under microwave-assisted conditions in two different forms (granules/dressing), whose chemical structure and morphology were studied. Their antioxidant properties have been proven. The chitosan-derived hemostatic agents exhibited superior blood sorption abilities and lack of cytotoxicity to L929 mouse fibroblasts. The study also showed the differences in biological properties depending on their preparation method. The potential mechanism of action was proposed as well as their potential in hemostasis revival.

Facile Synthesis of Surface-Modified Carbon Quantum Dots (CQDs) for Biosensing and Bioimaging.

Recently, fluorescent probes became one of the most efficient tools for biosensing and bioimaging. Special attention is focused on carbon quantum dots (CQDs), which are characterized by the water solubility and lack of cytotoxicity. Moreover, they exhibit higher photostability comparing to traditional organic dyes. Currently, there is a great need for the novel, luminescent nanomaterials with tunable properties enabling fast and effective analysis of the biological samples. In this article, we propose a new, ecofriendly bottom-up synthesis approach for intelligent, surface-modified nanodots preparation using bioproducts as a raw material. Obtained nanomaterials were characterized over their morphology, chemical structure and switchable luminescence. Their possible use as a nanodevice for medicine was investigated. Finally, the products were confirmed to be non-toxic to fibroblasts and capable of cell imaging.

Recovery and Characterization Studies of Post-Production Alloy Waste from the Automotive Industry.

Superalloys provide high corrosion resistance and are widely used as high-performance materials in aerospace, automotive, chemical, and other industries. Herein, the investigation into the characteristics and properties of alloy waste; Inconel 625, Inconel 718, and Titanium Grade 5, from the automotive industry, was introduced as a result of a recovery in various processes. For this reason, the following procedures were carried as follows; the washing process to remove oil from the swarf was evaluated using several commercial agents and for the process of thermal disposal of processing fluids, a temperature of 900 °C was used in a muffle furnace without air access. The presented studies show that the commercially available series of washing agents did not modify the composition of the surface. However, the high temperatures during the calcination of oil residues are affecting the elemental composition of the alloys. According to the results of the analyses, it is not possible to remove 100% of the oil residues from alloy waste using washing agents based on light organic fractions; however, the effectiveness of this method reaches 99%. In this report, accurate SEM-EDS analyses show changes that occur on the surface after machining and removal of processing fluids. The NMR and GC/MS investigations indicate contaminants as a mixture of aliphatic and cycloaliphatic hydrocarbons with carbon numbers from C8-C30.

3D Hierarchical, Nanostructured Chitosan/PLA/HA Scaffolds Doped with TiO2/Au/Pt NPs with Tunable Properties for Guided Bone Tissue Engineering.

Bone tissue is the second tissue to be replaced. Annually, over four million surgical treatments are performed. Tissue engineering constitutes an alternative to autologous grafts. Its application requires three-dimensional scaffolds, which mimic human body environment. Bone tissue has a highly organized structure and contains mostly inorganic components. The scaffolds of the latest generation should not only be biocompatible but also promote osteoconduction. Poly (lactic acid) nanofibers are commonly used for this purpose; however, they lack bioactivity and do not provide good cell adhesion. Chitosan is a commonly used biopolymer which positively affects osteoblasts' behavior. The aim of this article was to prepare novel hybrid 3D scaffolds containing nanohydroxyapatite capable of cell-response stimulation. The matrixes were successfully obtained by PLA electrospinning and microwave-assisted chitosan crosslinking, followed by doping with three types of metallic nanoparticles (Au, Pt, and TiO2). The products and semi-components were characterized over their physicochemical properties, such as chemical structure, crystallinity, and swelling degree. Nanoparticles' and ready biomaterials' morphologies were investigated by SEM and TEM methods. Finally, the scaffolds were studied over bioactivity on MG-63 and effect on current-stimulated biomineralization. Obtained results confirmed preparation of tunable biomimicking matrixes which may be used as a promising tool for bone-tissue engineering.

Hybrid Bilayer PLA/Chitosan Nanofibrous Scaffolds Doped with ZnO, Fe3O4, and Au Nanoparticles with Bioactive Properties for Skin Tissue Engineering.

Burns affect almost half a million of Americans annually. In the case of full-thickness skin injuries, treatment requires a transplant. The development of bioactive materials that promote damaged tissue regeneration constitutes a great alternative to autografts. For this reason, special attention is focused on three-dimensional scaffolds that are non-toxic to skin cells and can mimic the extracellular matrix, which is mainly composed of nanofibrous proteins. Electrospinning, which enables the preparation of nanofibers, is a powerful tool in the field of biomaterials. In this work, novel hybrid poly (lactic acid)/chitosan biomaterials functionalized with three types of nanoparticles (NPs) were successfully developed. ZnO, Fe3O4, and Au NPs were investigated over their morphology by TEM method. The top layer was obtained from PLA nanofibers, while the bottom layer was prepared from acylated chitosan. The layers were studied over their morphology by the SEM method and their chemical structure by FT-IR. To verify their potential in burn wound treatment, the scaffolds' susceptibility to biodegradation as well as moisture permeability were calculated. Also, biomaterials conductivity was determined in terms of electrostimulation. Finally, cytotoxicity tests were carried out by XTT assay and morphology analysis using both fibroblasts cell line and primary cells. The hybrid nanofibrous scaffolds displayed a great potential in tissue engineering.

Chitosan-Based Carbon Quantum Dots for Biomedical Applications: Synthesis and Characterization.

Rapid development in medicine and pharmacy has created a need for novel biomaterials with advanced properties such as photoluminescence, biocompability and long-term stability. The following research deals with the preparation of novel types of N-doped chitosan-based carbon quantum dots. Nanomaterials were obtained with simultaneous nitrogen-doping using biocompatible amino acids according to Green Chemistry principles. For the carbon quantum dots synthesis chitosan was used as a raw material known for its biocompability. The nanomaterials obtained in the form of lyophilic colloids were characterized by spectroscopic and spectrofluorimetric methods. Their quantum yields were determined. Additionally the cytotoxicity of the prepared bionanomaterials was evaluated by XTT (2,3-Bis-(2-methoxy-4-nitro5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt) method. Our results confirmed the formation of biocompatible quantum dots with carbon cores exhibiting luminescence in visible range. Performed studies showed that modification with lysine (11.5%) and glutamic acid (7.4%) had a high impact on quantum yield, whereas functionalization with amino acids rich in S and N atoms did not significantly increase in fluorescence properties. XTT assays as well as morphological studies on human dermal fibroblasts confirmed the lack of cytotoxicity of the prepared bionanomaterials. The study shows chitosan-based quantum dots to be promising for biomedical applications such as cell labelling, diagnostics or controlled drug delivery and release systems.

Luminescence phenomena of carbon dots derived from citric acid and urea - a molecular insight.

In this report, we present the results of our investigations into the elucidation of the chemical structure of moieties responsible for the blue and green luminescence of CDs derived from the microwave-assisted pyrolysis of citric acid in the presence of urea. The molecular fluorophore that forms during the synthesis of green fluorescing CDs is 4-hydroxy-1H-pyrrolo[3,4-c]pyridine-1,3,6(2H,5H)-trione (HPPT).