The characterization and biological activities of synthetic N, O-selenized chitosan derivatives

Double network self-healing hydrogels based on carboxyethyl chitosan/oxidized sodium alginate/Ca2+: Preparation, characterization and application in dye absorption

This paper presents the formation of a self-healing hydrogel prepared by carboxyethyl modification of chitosan and crosslinking with oxidized sodium alginate. Concurrently, the incorporation of Ca2+ facilitated the formation of "calcium bridges" through intricate coordination with carboxyl moieties, bolstering the attributes of the hydrogel. Various characterization methods, including scanning electron microscopy, texture analysis, and rheological measurements, demonstrated that the introduction of carboxyethyl groups resulted in a more compact hydrogel network structure and improved the hardness and elasticity. The addition of Ca2+ helped to further enhance the mechanical performance of the hydrogel and increase its thermal stability. Then, the adsorption capacity was also investigated, showing adsorption capacities of 46.17 mg/g methylene blue and 46.44 mg/g congo red for carboxyethyl chitosan/oxidized sodium alginate hydrogel, a four-fold increase for congo red versus chitosan/oxidized sodium alginate hydrogel. In addition, the adsorption behavior of CEC/OSA/2%Ca2+ hydrogel can be well described by pseudo-second-order kinetic model and Langmuir adsorption isothermal model. Compared to traditional hydrogels, CEC/OSA/2%Ca2+ hydrogel shows superior mechanical strength, enhanced thermal stability, and improved adsorption capacity, which can effectively adsorb not only methylene blue but also congo red. These advancements demonstrate our hydrogel's innovative properties.

Preparation, characterization and bioactivities of selenized polysaccharides from Lonicera caerulea L. fruits

Native polysaccharide was obtained from Lonicera caerulea L. fruits (PLP). Two selenized polysaccharides (PSLP-1 and PSLP-2) were synthesized by the microwave-assisted HNO₃-Na₂SeO₃ method, where the selenium (Se) contents were 228 ± 24 and 353 ± 36 μg/g, respectively. The molecular weights of PLP, PSLP-1, and PSLP-2 were 5.9 × 10⁴, 5.6 × 10⁴, and 5.1 × 10⁴ kDa, respectively. PSLP-1 and PSLP-2 contained the same type of monosaccharides as PLP but with different molar ratios. The main chain structure of the native polysaccharide was not changed after selenization. PLP, PSLP-1, and PSLP-2 contained the same six types of glycosidic bonds. Bioactivity assays revealed that the two selenized polysaccharides possessed better antioxidant activities than PLP, but their bile acid-binding abilities and inhibitory activities on acetylcholinesterase (AChE) had weakened. In summary, PLP, PSLP-1, and PSLP-2 may be promising Se supplements in functional foods and inhibitors for the treatment of AChE.

Beneficial Effect of Selenium Doped Carbon Quantum Dots Supplementation on the in vitro Development Competence of Ovine Oocytes

Background

After the synthesis of selenium doped carbon quantum dots (Se/CDs) via a step-by-step hydrothermal synthesis method with diphenyl diselenide (DPDSe) as precursor, the beneficial effects of Se/CDs’ supplementation on the in vitro development competence of ovine oocytes were firstly investigated in this study by the assay of maturation rate, cortical granules’ (CGs) dynamics, mitochondrial activity, reactive oxygen species (ROS) production, epigenetic modification, transcript profile, and embryonic development competence.

Results

The results showed that the Se/CDs’ supplementation during the in vitro maturation (IVM) process not only enhanced the maturation rate, CGs’ dynamics, mitochondrial activity and embryonic developmental competence of ovine oocytes, but remarkably decreased the ROS production level of ovine oocytes. In addition, the expression levels of H3K9me3 and H3K27me3 in the ovine oocytes were significantly up-regulated after the Se/CDs’ supplementation, in consistent with the expression levels of 5mC and 5hmC. Moreover, 2994 up-regulated differentially expressed genes (DEGs) and 846 repressed DEGs were found in the oocytes after the Se/CDs’ supplementation. According to the analyses of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), these DEGs induced by the Se/CDs’ supplementation were positively related to the progesterone mediated oocyte maturation and mitochondrial functions. And these remarkably up-regulated expression levels of DEGs related to oocyte maturation, mitochondrial function, and epigenetic modification induced by the Se/CDs’ supplementation further confirmed the beneficial effect of Se/CDs’ supplementation on the in vitro development competence of ovine oocytes.

Conclusion

The Se/CDs prepared in our study significantly promoted the in vitro development competence of ovine oocytes, benefiting the extended research about the potential applications of Se/CDs in mammalian breeding technologies.

Biopolymer from Water Kefir as a Potential Clean-Label Ingredient for Health Applications: Evaluation of New Properties

The present work aimed to characterize the exopolysaccharide obtained from water kefir grains (EPSwk), a symbiotic association of probiotic microorganisms. New findings of the technological, mechanical, and biological properties of the sample were studied. The EPSwk polymer presented an Mw of 6.35 × 10⁵ Da. The biopolymer also showed microcrystalline structure and characteristic thermal stability with maximum thermal degradation at 250 °C. The analysis of the monosaccharides of the EPSwk by gas chromatography demonstrated that the material is composed of glucose units (98 mol%). Additionally, EPSwk exhibited excellent emulsifying properties, film-forming ability, a low photodegradation rate (3.8%), and good mucoadhesive properties (adhesion Fmax of 1.065 N). EPSwk presented cytocompatibility and antibacterial activity against Escherichia coli and Staphylococcus aureus. The results of this study expand the potential application of the exopolysaccharide from water kefir as a potential clean-label raw material for pharmaceutical, biomedical, and cosmetic applications.

Novel Chitosan Derivatives and Their Multifaceted Biological Applications

Chitosan is a rather attractive material, especially because of its bio-origins as well as generation from exoskeletal waste. As the mantle has been effectively transferred from chitin to chitosan, so has it been extrapolated to in-house synthesized novel chitosan derivatives. This review comprehensively lists the available novel chitosan derivatives (ChDs) and summarizes their biological applications. The fact that chitosan derivatives do comprise multifaceted biological applications is attested by the voluminous reports on their varied contributions. However, this review points out to the fact that there has been selective focus on bio functions such as antifungal, antioxidant, antibacterial, whereas other biomedical applications and antiviral applications remain relatively less explored. With their current functionality record, there is definitely no doubt that the plethora of synthesized ChDs will have a profound impact on the unexplored biological aspects. This review points out this lacuna as room for future exploration.

Synthesis, characterization, and anti-tumor properties of O-benzoylselenoglycolic chitosan

This study introduces a facile method for synthesizing O-benzoylselenoglycolic chitosan with a high selenium concentration of 45.32 mg/g. The characterizations of the chemical structure via FTIR, ¹H NMR, ¹³C NMR, TGA, and XRD analyses indicated that benzoylselenoglycolic acid was successfully grafted onto the C6 hydroxyl group of chitosan. The anti-cancer activity of the O-benzoylselenoglycolic chitosan was investigated in vitro using a HepG2 cell model, and the results indicated that it has excellent anticancer activity against HepG2 cancer cells with an IC₅₀ value of 0.53 μg/mL while exhibiting non-toxicity against normal cells (L-02). Furthermore, a mechanistic study revealed that the O-benzoylselenoglycolic chitosan could induce early apoptosis, G2/M, S phase arrest, and activation of caspase-3 activity to inhibit the HepG2 cell growth. This study has led to novel organic selenium species, and the results suggest its potential to be used as an effective ingredient for cancer prevention and therapy in the food and pharmaceutical fields.

Organoselenium-chitosan derivative: Synthesis via "click" reaction, characterization and antioxidant activity

The derivatization of chitosan (CS) is widely exploited to endow this polysaccharide with enhanced physicochemical and biological properties. Beyond the synthetic route, the nature of the compounds used to functionalize the CS-derivatives exerts a pivotal role in their final properties. Making use of a simple "click" reaction, we synthesized for the first time an organoselenium-CS derivative through a 1,2,3-triazole formation. The product (CS-TSe) was characterized in detail by FTIR, NMR (¹H, ¹³C, and ⁷⁷Se) and UV-Vis techniques, and SEM microscopy. The antioxidant activity of CS-TSe was examined by ABTS⁺ and DPPH (free radical-scavenging) assays. Experimentally, it was demonstrated that CS-TSe has superior antioxidant activity compared with raw CS and "free" organoselenium compound, suggesting a benign and synergistic effect due to the derivatization. In short, the antioxidant property of CS-TSe combined with the other attractive properties of CS and selenium could be useful in the formulation of advanced materials for biomedical and packaging applications.