Recruitment of various biological macromolecules in fabrication of gold nanoparticles: Overview for preparation and applications

Algal carbohydrate polymers: Catalytic innovations for sustainable development

Algal polysaccharides, harnessed for their catalytic potential, embody a compelling narrative in sustainable chemistry. This review explores the complex domains of algal carbohydrate-based catalysis, revealing its diverse trajectory. Starting with algal polysaccharide synthesis and characterization methods as catalysts, the investigation includes sophisticated techniques like NMR spectroscopy that provide deep insights into the structural variety of these materials. Algal polysaccharides undergo various preparation and modification techniques to enhance their catalytic activity such as immobilization. Homogeneous catalysis, revealing its significance in practical applications like crafting organic compounds and facilitating chemical transformations. Recent studies showcase how algal-derived catalysts prove to be remarkably versatile, showcasing their ability to customise reactions for specific substances. Heterogeneous catalysis, it highlights the significance of immobilization techniques, playing a central role in ensuring stability and the ability to reuse catalysts. The practical applications of heterogeneous algal catalysts in converting biomass and breaking down contaminants, supported by real-life case studies, emphasize their effectiveness. In sustainable chemistry, algal polysaccharides emerge as compelling catalysts, offering a unique intersection of eco-friendliness, structural diversity, and versatile catalytic properties. Tackling challenges such as dealing with complex structural variations, ensuring the stability of the catalyst, and addressing economic considerations calls for out-of-the-box and inventive solutions. Embracing the circular economy mindset not only assures sustainable catalyst design but also promotes efficient recycling practices. The use of algal carbohydrates in catalysis stands out as a source of optimism, paving the way for a future where chemistry aligns seamlessly with nature, guiding us toward a sustainable, eco-friendly, and thriving tomorrow. This review encapsulates-structural insights, catalytic applications, challenges, and future perspectives-invoking a call for collective commitment to catalyze a sustainable scientific revolution.

Polysaccharide-based gold nanomaterials: Synthesis mechanism, polysaccharide structure-effect, and anticancer activity

Polysaccharide-based gold nanomaterials have attracted great interest in biomedical fields such as cancer therapy and immunomodulation due to their prolonged residence time in vivo and enhanced immune response. This review aims to provide an up-to-date and comprehensive summary of polysaccharide-based Au NMs synthesis, including mechanisms, polysaccharide structure-effects, and anticancer activity. Firstly, research progress on the synthesis mechanism of polysaccharide-based Au NMs was addressed, which included three types based on the variety of polysaccharides and reaction environment: breaking of glycosidic bonds via Au (III) or base-mediated production of highly reduced intermediates, reduction of free hydroxyl groups in polysaccharide molecules, and reduction of free amino groups in polysaccharide molecules. Then, the potential effects of polysaccharide structure characteristics (molecular weight, composition of monosaccharides, functional groups, glycosidic bonds, and chain conformation) and reaction conditions (the reaction temperature, reaction time, pH, concentration of gold precursor and polysaccharides) on the size and shape of Au NMs were explored. Finally, the current status of polysaccharide-based Au NMs cancer therapy was summarized before reaching our conclusions and perspectives.

Gold Nanoparticles Coated with SH-PEG-NH2 and Loaded with Ziyuglycoside I for Promoting Autophagy in Hematopoietic Stem Cells

Introduction

Radiotherapy and chemotherapy are the fundamental causes of myelosuppression in cancer patients, which usually induce a serious hematopoietic system toxicity, causing the hemocytes and immunity decline of patients. Ziyuglycoside I (ZgI), an active ingredient isolated from traditional Chinese medicine Sanguisorba officinalis L, has been demonstrated to increase the leucocytes and protect hematopoietic stem cells, which is related to its promotion of autophagy in hematopoietic stem cells.

Methods

In the present study, we formulated the SH-PEG-NH₂-coated gold nanoparticles loading ZgI (ZgI-AuNPs) with a enhanced autophagy promotion in hematopoietic stem cells. ZgI-AuNPs were prepared by HAuCl₄-sodium citrate reduction method, and the synthesis of ZgI-AuNPs was validated by XRD, FT-IR, DSC, and TEM findings. Furthermore, the drug loading rate and the release of ZgI were evaluated, and the ZgI-AuNPs' effects on autophagy and immunofluorescence staining for LC3B were tested. Finally, the effect of ZgI-AuNPs on the autophagy and hematopoietic ability of HSCs in vivo was also carried out.

Results

The prepared ZgI-AuNPs have an irregular cubic crystal structure by TEM observation, and the average particle size was 340 ± 16.5 nm determined by DLS. The XRD, FT-IR and DSC detection showed that the ZgI had been well loaded in AuNPs, and the AuNPs can load the ZgI at a content of 160.63 ± 1.35 μg·mg^-1. Meanwhile, the AuNPs can reduce the drug release rate of ZgI. Importantly, the ZgI-AuNPs enhanced autophagy of HSCs both in vitro and in vivo. At the same time, the gold nanoparticles enhance the hematopoietic effect of ZgI on mice HSCs.

Conclusion

Our research suggests that SH-PEG-NH₂-coated gold nanoparticles loading ZgI has potential application in myelosuppression therapy.

Synthesis and potential applications of trimetallic nanostructures

The present review highlights the synthetic strategies and potential applications of TMNs for organic reactions, environmental remediation, and health-related activities.

Nanobiocatalysts and photocatalyst in dye degradation

In the modern era, the world today is in a mission for a new method of environmental bioremediation in faltering the damage, especially in polluted water. Recently, the global direction is regulated toward an alteration from the usual chemical-based methods to a supplementary ecofriendly green alternative. In this perspective, biocatalysts are appreciated as an economical and clean substitute which was meant to catalyze degradation of unmanageable chemicals in a rapid, green and ecologically stable manner. Among the various sources of water pollution, the textile manufacturing industries were thought to be a major dispute due to release of effluents in natural water bodies such as rivers. Other industries like paper, pulp and tannery pharmaceutical industries were also responsible in contaminating the water bodies. Photocatalysis was considered as an auspicious method for the removal of dyes from the natural bodies, specifically those with hard organic compounds; using enzymes. The present chapter briefly emphasizes on the effective methods used for degradation of dye effluents; their importance of photocatalytic and biocatalytic solution to the current environmental difficulties and future opportunities are discussed.

An effective method for size-controlled gold nanoparticles synthesis with nonthermal microplasma

A simple, effective and interesting method for gold nanoparticles (AuNPs) synthesis with nonthermal microplasma is developed in this study. The device of dielectric barrier discharge (DBD) microplasma generator with a spray portion is designed and fabricated for uniform AuNPs synthesis. The AuNPs can be synthesized effectivelyin situby the DBD microplasma generated on the nozzle of the pneumatic micro-nebulizer. The mechanism of the AuNPs formation under microplasma, the effect of nebulization for uniform AuNPs synthesis and other significant parameters are investigated in the experiment. The morphology and optical properties of the synthesized gold nanoparticles are also characterized. The minimum particle size in average obtained by the proposed method is 4.9 ± 1.1 nm. The particle size of AuNPs can be controlled in the range of 4.9-16.8 nm by the various aqueous solution conditions.

One-pot synthesis of an anionic cyclodextrin-stabilized bifunctional gold nanoparticles for visual chiral sensing and catalytic reduction

A facile one-pot synthetic method for preparing gold nanoparticles by employing sugammadex (SUG), a carboxylic acid functionalized γ-cyclodextrin derivative, as reducing-cum-stabilizing agent herein was reported for the first time. The SUG protected gold nanoparticles (SUG-AuNPs) can work as a colorimetric sensor for visual chiral recognition of α-amino acids enantiomers, especially for lysine (Lys) and asparagine (Asn) enantiomers. The chiral recognition assay was successfully applied to determining the enantiometric excess of L-Lys and L-Asn ranging from -100 % to 100 % respectively. Moreover, the prepared SUG-AuNPs was found to exhibit efficient catalytic activity towards the reduction of toxic 4-nitrophenol by NaBH₄ and the efficiency of the system was further demonstrated through the reduction of other typical nitroaromatics under mild condition. The as-synthesized SUG-AuNPs shows good performance for both chiral sensing and reduction activity and thus may facilitate the practical application in the area of both chiral discrimination and catalysis.

Green polymeric nanomaterials for the photocatalytic degradation of dyes: a review

Pure and drinkable water will be rarer and more expensive as the result of pollution induced by industrialisation, urbanisation and population growth. Among the numerous sources of water pollution, the textile industry has become a major issue because effluents containing dyes are often released in natural water bodies. For instance, about two years are needed to biodegrade dye-derived, carcinogenic aromatic amines, in sediments. Classical remediation methods based upon physicochemical reactions are costly and still generate sludges that contain amine residues. Nonetheless, recent research shows that nanomaterials containing biopolymers are promising to degrade organic pollutants by photocatalysis. Here, we review the synthesis and applications of biopolymeric nanomaterials for photocatalytic degradation of azo dyes. We focus on conducting biopolymers incorporating metal, metal oxide, metal/metal oxide and metal sulphide for improved biodegradation. Biopolymers can be obtained from microorganisms, plants and animals. Unlike fossil-fuel-derived polymers, biopolymers are carbon neutral and thus sustainable in the context of global warming. Biopolymers are often biodegradable and biocompatible.