Novel Pt-Ag3PO4/CdS/Chitosan Nanocomposite with Enhanced Photocatalytic and Biological Activities

A review on versatile applications of biomaterial/polycationic chitosan: An insight into the structure-property relationship

Chitosan is a versatile and generous biopolymer obtained by alkaline deacetylation of naturally occurring chitin, the second most abundant biopolymer after cellulose. The excellent physicochemical properties of polycationic chitosan are attributed to the presence of varied functional groups such as amino, hydroxyl, and acetamido groups enabling researchers to tailor the structure and properties of chitosan by different methods such as crosslinking, grafting, copolymerization, composites, and molecular imprinting techniques. The prepared derivatives have diverse applications in the food industry, water treatment, cosmetics, pharmaceuticals, agriculture, textiles, and biomedical applications. In this review, numerous applications of chitosan and its derivatives in various fields have been discussed in detail with an insight into their structure-property relationship. This review article concludes and explains the chitosan's biocompatibility and efficiency that has been done so far with future usage and applications as well. Moreover, the possible mechanism of chitosan's activity towards several emerging fields such as energy storage, biodegradable packaging, photocatalysis, biorefinery, and environmental bioremediation are also discussed. Overall, this comprehensive review discusses the science and complete information behind chitosan's wonder function to improve our understanding which is much needful as well as will pave the way towards a sustainable future.

Biopolymeric Ni3S4/Ag2S/TiO2/Calcium Alginate Aerogel for the Decontamination of Pharmaceutical Drug and Microbial Pollutants from Wastewater

The ubiquitous presence of pharmaceutical drugs and microbes in the water is leading to the development of drug resistant microbes. Therefore, efficient materials that can remove or inactivate the drug and microbe contaminants are required. In this work, nickel sulfide/calcium alginate (Ni3S4/CA), silver sulfide/calcium alginate (Ag2S/CA), modified titanium dioxide/calcium alginate (TiO2/CA), and Ni3S4/Ag2S/TiO2/calcium alginate (Ni3S4/Ag2S/TiO2/CA) aerogels have been synthesized for the removal of the oxytetracycline (OTC) drug and microbial contaminants from real beverage industry wastewater. The results revealed that Ni3S4/Ag2S/TiO2/CA aerogel is highly efficient for OTC adsorption and inactivation of microbes compared to Ni3S4/CA, Ag2S/CA and TiO2/CA aerogels. The OTC adsorption depends greatly on the solution pH, and optimum OTC removal was observed at pH 6 in its zwitterionic (OTC±) form. The formation of H-bonding and n-π electron donor-acceptors is possible to a considerable extent due to the presence of the double bond benzene ring, oxygen and nitrogen, sulfur-containing functional groups on the OTC molecules, and the Ni3S4/Ag2S/TiO2/CA aerogel. Based on the statistical analysis, root-mean-square deviation (RMSD), chi square (χ2) values, and higher correlation coefficient (R2) values, the Redlich−Peterson isotherm model and Elovich kinetic model are most suited to modelling the OTC adsorption onto Ni3S4/Ag2S/TiO2/CA. The prepared aerogels’ excellent antimicrobial activity is observed in the dark and with solar light irradiation. The zone of inhibition analysis revealed that the antimicrobial activity of the aerogels is in the following order: Ni3S4/Ag2S/TiO2/CA > TiO2/CA > Ag2S/CA > Ni3S4/CA, respectively. Moreover, the antimicrobial results demonstrated that reactive oxygen species, electrons, and active radical species are responsible for growth inhibition and killing of the microbes. These results indicated that Ni3S4/Ag2S/TiO2/CA aerogel is highly efficient in decontaminating pollutants from wastewater.

Essential oil-mediated biocompatible magnesium nanoparticles with enhanced antibacterial, antifungal, and photocatalytic efficacies

Emergent application of antimicrobial strategies as symptomatic treatment in coronavirus disease (COVID-19) and linkage of severe acute respiratory syndrome coronavirus2 with microbial infections, has created colossal demand for antimicrobials. For the first time, this communication explore the physicochemical, antifungal, antibacterial, and photocatalytic properties of biogenic magnesium nanoparticles (MgNPs), synthesized using essential oil of Cymbopogon flexuosus's as an efficient multifunctional reducing and stabilizing/capping reagent. It is observed that MgNPs (ranging in size: 8–16 nm) of varying phytochemical compositions (MgS1, MgS2, MgS3) exhibited various useful physicochemical, antimicrobial, and photocatalytic properties. FTIR outcomes highlight the functional biomolecules-assisted reduction of Mg from Mg⁺ to Mg⁰. Among all, MgS3-Nps owing to the smallest particle size exhibited superior photocatalytic efficacy (91.2%) for the methylene blue degradation upon direct exposure to the sunlight for 3 h without using any reducing agents. Fabricated MgNPs also exhibited excellent antifungal (against Fusarium oxysporum) and antibacterial (versus Staphylococcus aureus and Escherichia coli) efficacies compared to state-of-the-art antimicrobial agents deployed for the treatment of infectious diseases. Based on this investigated greener approach, imperative from economic and environmental viewpoint, such essential oil based-MgNPs can be a potential nanosystem for various industrial applications where photocatalytic, and biomedical attributes are the key requirements.

Ultrasonic-Assisted Synthesis of CdS/Microcrystalline Cellulose Nanocomposites With Enhanced Visible-Light-Driven Photocatalytic Degradation of MB and the Corresponding Mechanism Study

A simple and efficient ultrasonic-assisted approach was designed to synthesize CdS/microcrystalline cellulose (MCC) nanocomposite photocatalyst. The obtained products have been characterized by XRD, FE-SEM, TEM, UV-Vis DRS, and nitrogen adsorption isotherms. The results showed that the intimate contact of MCC and CdS is beneficial for enhancing the photocatalytic performance because heterojunction formation can efficiently promote the separation of photogenerated electrons and holes of the nanocomposite photocatalyst. By using 10% MCC coupled CdS, the decoloration rate of methylene blue (MB) in the solution under visible-light was increased nearly 50%. In addition, the reuse experiments confirmed that the CdS/MCC nanocomposite photocatalyst had outstanding cycle performance and durability. Mechanism study demonstrated that hydroxyl radicals, photogenerated holes and superoxide radicals were the active species in the photocatalytic oxidization degradation of MB.

Silver and Gold Nanoparticles for Antimicrobial Purposes against Multi-Drug Resistance Bacteria

Several pieces of research have been done on transition metal nanoparticles and their nanocomplexes as research on their physical and chemical properties and their relationship to biological features are of great importance. Among all their biological properties, the antibacterial and antimicrobial are especially important due to their high use for human needs. In this article, we will discuss the different synthesis and modification methods of silver (Ag) and gold (Au) nanoparticles and their physicochemical properties. We will also review some state-of-art studies and find the best relationship between the nanoparticles’ physicochemical properties and potential antimicrobial activity. The possible antimicrobial mechanism of these types of nanoparticles will be discussed in-depth as well.

Green porous benzamide-like nanomembranes for hazardous cations detection, separation, and concentration adjustment

Green biomaterials play a crucial role in the diagnosis and treatment of diseases as well as health-related problem-solving. Typically, biocompatibility, biodegradability, and mechanical strength are requirements centered on biomaterial engineering. However, in-hospital therapeutics require an elaborated synthesis of hybrid and complex nanomaterials capable of mimicking cellular behavior. Accumulation of hazardous cations like K⁺ in the inner and middle ear may permanently damage the ear system. We synthesized nanoplatforms based on Allium noeanum to take the first steps in developing biological porous nanomembranes for hazardous cation detection in biological media. The 1,1,1-tris[[(2'-benzyl-amino-formyl)phenoxy]methyl]ethane (A), 4-amino-benzo-hydrazide (B), and 4-(2-(4-(3-carboxy-propan-amido)benzoyl)hydrazineyl)-4-oxobutanoic acid (B1) were synthesized to obtain green ligands based on 4-X-N-(…(Y(hydrazine-1-carbonyl)phenyl)benzamide, with X denoting fluoro (B2), methoxy (B3), nitro (B4), and phenyl-sulfonyl (B5) substitutes. The chemical structure of ligand-decorated adenosine triphosphate (ATP) molecules (S-ATP) was characterized by FTIR, XRD, AFM, FESEM, and TEM techniques. The cytotoxicity of the porous membrane was patterned by applying different cell lines, including HEK-293, PC12, MCF-7, HeLa, HepG2, and HT-29, to disclose their biological behavior. The morphology of cultured cells was monitored by confocal laser scanning microscopy. The sensitivity of S-ATP to different cations of Na⁺, Mg²⁺, K⁺, Ba²⁺, Zn²⁺, and Cd²⁺ was evaluated by inductively coupled plasma atomic emission spectroscopy (ICP-AES) in terms of extraction efficiency (η). For pH of 5.5, the η of A-based S-ATP followed the order Na⁺ (63.3%) > Mg²⁺ (62.1%) > Ba²⁺ (7.6%) > Ca²⁺ (5.5%); while for pH of 7.4, Na⁺ (37.0%) > Ca²⁺ (33.1%) > K⁺ (25^.7%). The heat map of MTT and dose-dependent evaluations unveiled acceptable cell viability of more than 90%. The proposed green porous nanomembranes would pave the way to use multifunctional green porous nanomembranes in biological membranes.

Crystalline polysaccharides: A review

The biodegradability and mechanical properties of polysaccharides are dependent on their architecture (linear or branched) as well as their crystallinity (size of crystals and crystallinity percent). The amount of crystalline zones in the polysaccharide significantly governs their ultimate properties and applications (from packaging to biomedicine). Although synthesis, characterization, and properties of polysaccharides have been the subject of several review papers, the effects of crystallization kinetics and crystalline domains on the properties and application have not been comprehensively addressed. This review places focus on different aspects of crystallization of polysaccharides as well as applications of crystalline polysaccharides. Crystallization of cellulose, chitin, chitosan, and starch, as the main members of this family, were discussed. Then, application of the aforementioned crystalline polysaccharides and nano-polysaccharides as well as their physical and chemical interactions were overviewed. This review attempts to provide a complete picture of crystallization-property relationship in polysaccharides.