Chitosan capped Au@Pd@Ag trimetallic nanoparticles: Synthesis, stability, capping action and adsorbing activities

Enhanced applications in dentistry through autoclave-assisted sonochemical synthesis of Pb/Ag/Cu trimetallic nanocomposites

In recent years, researchers have increasingly focused on the development of multiphase trimetallic nanocomposites (TMNC) incorporating ternary metals or metal oxides, which hold significant potential as alternatives for combatting biofilms and bacterial infections. Enhanced oral health is ensured by the innovative techniques used to effectively prevent bacterial adherence and formation of biofilm on dental sutures. In this investigation, TMNC, which consists of Pb, Ag, and Cu, was synthesized using an autoclave-assisted sonochemical technique. Following synthesis, TMNC were characterized using FTIR, XRD, BET, XPS, TGA, and Raman spectroscopy to analyze their shape and microstructure. Subsequent evaluations, including MTT assay, antibacterial activity testing, and biofilm formation analysis, were conducted to assess the efficiency of the synthesized TMNC. Cytotoxicity and anti-human oral squamous cell carcinoma activities of TMNC were evaluated using the Human Oral Cancer cell line (KB) cell line through MTT assay, demonstrating a dose-dependent increase in anti-human oral squamous cell carcinoma activity against the KB cell line compared to the normal cell line, resulting in notably high cell viability. Furthermore, an ultrasonic probe was employed to incorporate TMNC onto dental suturing threads, with different concentrations of TMNC, ultrasonic power levels, and durations considered to determine optimal embedding conditions that result in the highest antibacterial activity. The inhibitory effects of TMNC, both in well diffusion assays and when incorporated into dental suturing threads, against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria on Mueller-Hinton agar (MHA) were assessed using various concentrations of TMNC. The results of the study indicated that the efficacy of TMNC in inhibiting bacterial growth on dental suturing threads remained impressive, even at low concentrations. Moreover, an evaluation of their potential to destabilize biofilms formed by S. aureus and E. coli, the two pathogens in humans, indicated that TMNC would be a promising anti-biofilm agent.

Encapsulation of Citrus sinensis essential oil and R-limonene in lipid nanocarriers: A potential strategy for the treatment of leishmaniasis

Leishmaniases, a group of neglected tropical diseases caused by an intracellular parasite of the genus Leishmania, have significant impacts on global health. Current treatment options are limited due to drug resistance, toxicity, and high cost. This study aimed to develop nanostructured lipid carriers (NLCs) for delivering Citrus sinensis essential oil (CSEO) and its main constituent, R-limonene, against leishmaniasis. The influence of surface-modified NLCs using chitosan was also examined. The NLCs were prepared using a warm microemulsion method, and surface modification with chitosan was achieved through electrostatic interaction. These nanocarriers were characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electron microscopy, and dynamic light scattering (DLS). In vitro cytotoxicity was assessed in L929 and RAW 264.7 cells, and leishmanicidal activity was evaluated against promastigote and amastigote forms. The NLCs were spherical, with particle sizes ranging from 97.9 nm to 111.3 nm. Chitosan-coated NLCs had a positive surface charge, with zeta potential values ranging from 45.8 mV to 59.0 mV. Exposure of L929 cells to NLCs resulted in over 70 % cell viability. Conversely, surface modification significantly reduced the viability of promastigotes (93 %) compared to free compounds. Moreover, chitosan-coated NLCs presented a better IC50 against the amastigote forms than uncoated NLCs. Taken together, these findings demonstrate the feasibility of using NLCs to overcome the limitations of current leishmaniasis treatments, warranting further research.

Fabrication of uniform Pd nanoparticles immobilized on crosslinked ionic chitosan support as a super-active catalyst toward regioselective synthesis of pyrazole-fused heterocycles

Selection of biodegradable chitosan as a raw material is a smart technique due to its easy modifiability and high renewability. Herein, taking advantage of these functional characteristics, an ionic biopolymer support is produced from copolymerization of allylated chitosan (with 48 % degree of substitution) and polymerizable ionic liquid ([MEVIm]Br). Next, palladium nanoparticles are successfully stabilized in this designed support through a facile manner based on interconnected porous network, ionic nature and rich functional groups. Then, the Pd@CS-PIL structure was utilized as a heterogeneous catalyst for regioselective synthesis of pyrazole-fused heterocycles. The as-synthesized Pd@CS-PIL was characterized by various techniques such as XRD, EDX, FESEM, elemental mapping, TEM, BET, ICP, TGA, and FT-IR to better determine the structure, morphology, purity and physical properties. The obtained results revealed that the proposed nanostructure provides favorable porosity with significant specific surface area (139.2 m2.g-1), Pd nanoparticles with high dispersion (mean diameter ∼ 22.8 nm) and crosslinked nature with good thermal stability (50 % weight loss about 600 °C). Therefore, Pd@CS-PIL nanostructure showed the key features of a super-active catalyst, and pharmaceutical pyrazole-fused scaffolds were produced in favorable yields (86-96 %) under ultrasound conditions.

Advancements in Composite Materials and Their Expanding Role in Biomedical Applications

The synthesis of a Ni-doped ZnO nanocomposite incorporating chitosan (CS/Ni-doped ZnO) was achieved via a precipitation method, followed by annealing at 250 °C. This study comprehensively examined the nanocomposite's structural, functional, morphological, and porosity properties using various analytical techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), high-resolution scanning electron microscopy (HR-SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) analysis. The presence of chitosan (CS) and nickel (Ni) within the nanocomposite, along with their influence on reducing the band gap of ZnO particles and enhancing the generation of electron-hole pairs, was confirmed using UV-visible near-infrared spectroscopy (UV-vis-NIR). The electrochemical properties of the CS/Ni-doped ZnO nanocomposite were investigated via electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) by utilizing a phosphate buffer solution with a pH of 6, which closely resembled the typical pH of bacterial cell walls. Finally, the prepared CS/Ni-doped ZnO nanocomposite was evaluated for its antibacterial and anticancer activities. The results demonstrated the highest inhibition of bacterial growth in P. vulgaris, whereas the lowest inhibition was found in S. aureus across various concentrations, thus highlighting its potential in antimicrobial applications. The cytotoxicity of CS/Ni-doped ZnO nanocomposites demonstrated remarkable effects with a half-maximum inhibitory concentration of approximately 80 ± 0.23 µg mL-1 against MCF-7 breast cancer cell lines, following a dose-dependent manner.

Modification of multi-walled carbon nanotubes with platinum-osmium to develop stable catalysts for direct methanol fuel cells

In the study, a new bimetallic catalyst was synthesized for methanol oxidation using multi-walled carbon nanotube (MWCNT)-supported platinum-osmium (PtOs) nanoparticles (PtOs@MWCNT NPs). The morphological structures of the prepared NPs were examined using different techniques, such as scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical characterization of the synthesized PtOs@MWCNT catalysts, such as chronoamperometry (CA), cyclic voltammetry (CV), scan rate (SR) analysis, cyclic catalytic test, and electrochemical surface area (ECSA) evaluation, were performed in an alkaline medium. From the results obtained, the size of the NPs was found to be 3.12 nm according to the Debye-Schrrer equation, and the MWCNTs were clearly observed by SEM imaging. After the characterization of the prepared nanomaterials, the PtOs@MWCNT catalysts were employed in the methanol oxidation reaction, and a high oxidation current value of 220.86 mA cm^-2 was observed. Besides, according to the CA results, the catalyst exhibited high stability for 4000 s, and it was seen that Os metal improved the catalytic activity of the main catalyst. These results show that the PtOs@MWCNT catalyst is highly stable and reusable, and provides high electrocatalytic activity in the methanol oxidation reaction. Moreover, the obtained catalyst gave ideal results in terms of CO tolerance and activity. These data show that the obtained catalyst will provide significant improvement and superior efficiency in fuel-cell applications.

Fabrication of chitosan-MnO2‑iridium/nanoceria supported nanoparticles: Catalytic and anti-radical activities

Chitosan capped MnO₂‑iridium nanoparticles supported on nanoceria (Ch-MnO₂-Ir/CeO₂) were fabricated by using combination of colloidal solution and metal displacement galvanic methods. The oxidative degradation of acid orange 7 in aqueous solution by activated persulfate with the as-prepared nanoparticles was studied. The resulting Ch-MnO₂-Ir/CeO₂ with S₂O₈^2-, 80 % degraded 70.06 mg/L of acid orange 7 within 100 min, while at the same time, Ch-Ir, Ch-MnO₂, and Ch-Ir-MnO₂ remained inactive. CeO₂ increased the surface of the catalyst, and also improved the reactive oxygen species site of Ch-Ir-MnO₂ through the activation of S₂O₈^2- with CeO₂. The reversible redox cycle reaction, Ce (III) ↔ Ce (IV) and strong synergistic effect of MnO₂-Ir are responsible for the remarkable catalytic performance of Ch-MnO₂-Ir/CeO₂/S₂O₈^2- system. The degradation of acid orange 7 could be significantly retarded with inorganic (NO₃^- < Cl^- < SO₄^2- < H₂PO₄^- < HCO₃^-) and organic scavengers (ethanol < tertiary butanol < benzoquinone < phenol). Ch-MnO₂-Ir/CeO₂ exhibited excellent stability and reusability. Anti-radical activity of chitosan and Ch-MnO₂-Ir/CeO₂ was evaluated with 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical. The free radical properties increase with concentration of chitosan and Ch-MnO₂-Ir/CeO₂.

Chitosan functionalized with N,N-(2-aminoethyl)pyridinedicarboxamide for selective adsorption of gold ions from wastewater

The recovery of gold from wastewater has always been a research hotspot. Here, a novel chitosan-based adsorbent (CS-DPDM) was successfully synthesized by functionalizing chitosan with (N, N-(2-aminoethyl))-2,6-pyridinedicarboxamide. The adsorbent was analyzed by fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (¹H NMR), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and zeta potential method (Zeta). To investigate the adsorption performance of CS-DPDM for Au(III), the effects of pH, temperature, adsorption time and initial concentration were discussed. The maximum adsorption capacity of CS-DPDM for Au(III) at pH 5.0 is 659.02 mg/g at 318 K. The adsorption is a spontaneous endothermic behavior, and the adsorption process follows the quasi-second-order kinetic and Langmuir isotherm models, indicating that a single layer of chemical adsorption may have occurred on the surface of the adsorbent. The competitive adsorption and repetitive experiments show that CS-DPDM has considerable selectivity and reusability for Au(III). X-ray photoelectron spectroscopy (XPS) results show that N and O functional groups adsorb Au(III) on the surface of CS-DPDM through electrostatic, chelation and reduction. These results indicate that CS-DPDM has broad application prospects in recovering gold ions from aqueous solutions.

Chitosan capped trimetallic nanoparticles: Synthesis and their Congo red adsorbing activities

Chitosan capped Fe⁰-based Fe-Pd-Ir (Chi-Fe-Pd-Ir) tri-metallic nanoparticles were fabricated using metal displacement method in presence of sodium borohydride. The preliminary indications of Fe⁰ production were the appearance of pale yellow color with ferric nitrate, NaBH₄, and chitosan. Chitosan was detected by using ninhydrin color test, thermal gravimetric analysis and measurement of relative viscosity. The average molecular weight of chitosan and Chi-Fe-Pd-Ir decreased with increased potassium persulfate concentration. Chi-Fe-Pd-Ir used as an adsorbent for the removal of Congo red. The sorption equilibrium data were fitted into Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms (DRK). The maximum monolayer adsorption capacity (Q⁰_max), and sorption intensity (n) were estimated to be 93.4 mg/g and 2.0, respectively, from Langmuir and Freundlich adsorption isotherm models. The mean free energy was calculated by using DRK isotherm to be 0.15 kJ/mol. Sorption parameters indicate that the Congo red adsorbed on the surface of Chi-Fe-Pd-Ir through monolayer formation via physisorption process. The adsorption of CR on Chi-Fe-Pd-Ir was in good agreement with the Langmuir adsorption isotherm and pseudo-second-order kinetic model. Protonated amino group of chitosan was also responsible for the adsorption of anionic CR along with the Fe-Pd-Ir NPs.

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.

Chitosan: An Overview of Its Properties and Applications

Chitosan has garnered much interest due to its properties and possible applications. Every year the number of publications and patents based on this polymer increase. Chitosan exhibits poor solubility in neutral and basic media, limiting its use in such conditions. Another serious obstacle is directly related to its natural origin. Chitosan is not a single polymer with a defined structure but a family of molecules with differences in their composition, size, and monomer distribution. These properties have a fundamental effect on the biological and technological performance of the polymer. Moreover, some of the biological properties claimed are discrete. In this review, we discuss how chitosan chemistry can solve the problems related to its poor solubility and can boost the polymer properties. We focus on some of the main biological properties of chitosan and the relationship with the physicochemical properties of the polymer. Then, we review two polymer applications related to green processes: the use of chitosan in the green synthesis of metallic nanoparticles and its use as support for biocatalysts. Finally, we briefly describe how making use of the technological properties of chitosan makes it possible to develop a variety of systems for drug delivery.

A Novel Chitosan Nanosponge as a Vehicle for Transepidermal Drug Delivery

Transepidermal drug delivery achieves high drug concentrations at the action site and ensures continuous drug delivery and better patient compliance with fewer adverse effects. However, drug delivery through topical application is still limited in terms of drug penetration. Chitosan is a promising enhancer to overcome this constraint, as it can enhance drug diffusion by opening the tight junctions of the stratum corneum. Therefore, here, we developed a novel chitosan nanosponge (CNS) with an optimal ratio and molecular weight of chitosan to improve drug penetration through skin. To prepare the CNS, two types of chitosan (3 and 10 kDa) were each conjugated with poloxamer 407 using para-nitrophenyl chloroformate, and the products were mixed with poloxamer 407 at ratios of 5:5, 8:2, and 10:0. The resulting mixtures were molded to produce flexible soft nanosponges by simple nanoprecipitation. The CNSs were highly stable in biological buffer for four weeks and showed no toxicity in human dermal fibroblasts. The CNSs increased drug permeability through human cadaver skin in a Franz-type diffusion cell, with substantially higher permeability with 3 kDa chitosan at a ratio of 8:2. This suggests the applicability of the novel CNS as a promising carrier for efficient transepidermal drug delivery.

Determination of chitosan content with Schiff base method and HPLC

Tremendous awareness of determination of chitosan content accurately is increasing, due to it has great significance to the quality control of chitosan. In this article, two kinds of chitosan-Schiff base derivatives (BCSB and PCSB) were synthesized by the different average degrees of deacetylation (DD) of chitosan with benzaldehyde or propanal, respectively. The total mass of Schiff base derivative product was dried and obtained without washing and loss. Then, a certain amount of the prepared Schiff base compound was taken to hydrolyze into glucosamine hydrochloride (GAH) in strong hydrochloric acidic environment, whose concentration was quantified by HPLC, and the mass of GAH contained in hydrolysis solution could be calculated. Subsequently, the total quality of GAH obtained by hydrolysis of all of the Schiff base product was calculated and obtained, and then the theoretical mass of chitosan could be deduced and calculated by further converse calculation. Finally, the chitosan content was obtained by combining the sample mass used in Schiff base reaction and the theoretical mass of chitosan. This method was accurate and convenient, providing a preeminent idea and method for the determination of chitosan content.

Facile One-Pot Biogenic Synthesis of Cu-Co-Ni Trimetallic Nanoparticles for Enhanced Photocatalytic Dye Degradation

Biomolecules from plant extracts have gained significant interest in the synthesis of nanoparticles owing to their sustainable properties, cost efficiency, and environmental wellbeing. An eco-friendly and facile method has been developed to prepare Cu-Co-Ni trimetallic nanoparticles with simultaneous bio-reduction of Cu-Co-Ni metal precursors by aqueous extract of oregano (Origanum vulgare) leaves. Dramatic changes in physicochemical properties of trimetallic nanoparticles occur due to synergistic interactions between individual metal precursors, which in turn outclass the properties of corresponding monometallic nanoparticles in various aspects. The as biosynthesized Cu-Co-Ni trimetallic nanoparticles were initially analyzed using ultraviolet (UV)–visible spectroscopy. The morphology, structure, shape, and size of biosynthesized trimetallic nanoparticles were confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) spectroscopy. The elemental analysis was carried out by energy-dispersive X-ray (EDX) spectroscopy. Fourier transform infrared (FTIR) microscopy was carried out to explain the critical role of the biomolecules in the Origanum vulgare leaf extract as capping and stabilizing agents in the nanoparticle formation. Additionally, simultaneous thermogravimetric analysis (TGA) and differential thermogravimetry (DTG) analysis was also performed to estimate the mass evaluation and rate of the material weight changes. The photocatalytic activity of as biosynthesized trimetallic nanoparticles was investigated towards methylene blue (MB) dye degradation and was found to be an efficient photocatalyst for dye degradation. Kinetic experiments have shown that photocatalytic degradation of MB dye followed pseudo-first-order kinetics. The mechanism of the photodegradation process of biogenic Cu-Co-Ni trimetallic nanoparticles was also addressed.

Trimetallic Nanoparticles: Greener Synthesis and Their Applications

Nanoparticles (NPs) and multifunctional nano-sized materials have significant applications in diverse fields, namely catalysis, sensors, optics, solar energy conversion, cancer therapy/diagnosis, and bioimaging. Trimetallic NPs have found unique catalytic, active food packaging, biomedical, antimicrobial, and sensing applications; they preserve an ever-superior level of catalytic activities and selectivity compared to monometallic and bimetallic nanomaterials. Due to these important applications, a variety of preparation routes, including hydrothermal, microemulsion, selective catalytic reduction, co-precipitation, and microwave-assisted methodologies have been reported for the syntheses of these nanomaterials. As the fabrication of nanomaterials using physicochemical methods often have hazardous and toxic impacts on the environment, there is a vital need to design innovative and well-organized eco-friendly, sustainable, and greener synthetic protocols for their assembly, by applying safer, renewable, and inexpensive materials. In this review, noteworthy recent advancements relating to the applications of trimetallic NPs and nanocomposites comprising these NPs are underscored as well as their eco-friendly and sustainable synthetic preparative options.

Chitosan modified metal–organic frameworks as a promising carrier for oral drug delivery

The drug delivery system of CS-MOF@5-FU was developed to achieve oral administration of 5-FU.