Synthesis, characterization, antimicrobial and antioxidant study of the facile sonochemically synthesized SnS2 nanoparticles

Ultrasound-Assisted Synthesis of SnS2 Quantum Dots Using Acetone as Solvent

A sonochemical synthesis of SnS2 quantum dots using acetone as a solvent is investigated. Two different tin sources (SnCl2∙2H2O or SnCl4∙5H2O) as well as two different sulfur sources (thioacetamide or Na2S2O3) were applied. The sonication time was also varied between 60 and 120 min. Resulting products of syntheses were characterized with the following techniques: powder X-ray diffraction, electron microscopy (SEM and HR-TEM), Raman and FT-IR spectroscopies, the Tauc method, and X-ray photoelectron spectroscopy. Obtained SnS2 nanostructures were in the form of quantum dots in the case of synthesis lasting 60 min (size of crystallites in the range of 3.5-7 nm) and in the form of elongated nanorods of length ca. 25-30 nm and width of 5-6 nm in the case of synthesis lasting 120 min. XPS analyses revealed that the surface of the obtained products contained a significant amount of tin at the second oxidation state (i.e., SnS). The quantum dots produced in the synthesis lasting 60 min showed a value of energy bandgap of 2.7 eV indicating potential applications in photocatalysis.

Biomedical prospects and challenges of metal dichalcogenides nanomaterials

The biomedical applications of metal dichalcogenides (MDCs) nanomaterials (NMs) are an emerging discipline because of their unique attributes like high surface-to-volume ratio, defect sites, superb catalytic performance, and excitation-dependent emission, which is helpful in bio-imaging and cancer cell killing. Due to the compatibility of sensing material with cells and tissues, MoS2, WS2, and SnS2NMs have piqued the interest of researchers in various biomedical applications like photothermal therapy used in killing cancer cells, drug delivery, photoacoustic tomography (PAT) used in bio-imaging, nucleic acid or gene delivery, tissue engineering, wound healing, etc. Furthermore, these NMs' functionalization and defect engineering can enhance therapeutic efficacy, biocompatibility, high drug transport efficiency, adjustable drug release, dispersibility, and biodegradability. Among the aforementioned materials, MoS2NMs have extensively been explored via functionalization and defects engineering to improve biosensing properties. However, further enhancement is still available. Aside from MoS2, the distinct chemo-physical and optical features of WS2and SnS2NMs promise considerable potential in biosensing, nanomedicine, and pharmaceuticals. This article mainly focuses on the challenges and future aspects of two-dimensional MDCs NMs in biomedical applications, along with their advancements in various medical diagnosis processes.

Sonochemical synthesis of SnS and SnS2 quantum dots from aqueous solutions, and their photo- and sonocatalytic activity

Our study reports the ultrasound-assisted synthesis of SnS and SnS2 in the form of nanoparticles using aqueous solutions of respective tin chloride and thioacetamide varying sonication time. The presence of both compounds is confirmed by powder X-ray diffraction, energy-dispersive X-ray spectroscopy, as well as Raman and FT-IR spectroscopic techniques. The existence of nanoparticles is proven by powder X-ray diffraction investigation and by high resolution transmission electron microscopy observations. The size of nanocrystallites are in the range of 3-8 nm and 30 50 nm for SnS, and 1.5-10 nm for SnS2. X-ray photoelectron spectroscopy measurements, used to investigate the chemical state of tin and sulphur atoms on the surface of nanoparticles, reveal that they are typically covered with tin on the same oxidation degree as respective bulk compound. Values of optical bandgaps of synthesized nanoparticles, according to the Tauc method, were 2.31, 1.47 and 1.05 eV for SnS (60, 90 and 120 min long synthesis, respectively), and 2.81, 2.78 and 2.70 eV for SnS2 (60, 90 and 120 min long synthesis, respectively). Obtained nanoparticles were utilized as photo- and sonocatalysts in the process of degradation of model azo-dye molecules by UV-C light or ultrasound. Quantum dots of SnS2 obtained under sonication lasting 120 min were the best photocatalyst (66.9 % color removal), while quantum dots of SnS obtained under similar sonication time were the best sonocatalyst (85.2 % color removal).

Dye-Modified, Sonochemically Obtained Nano-SnS2 as an Efficient Photocatalyst for Metanil Yellow Removal

We investigate the possibility of modification of SnS2 powder through sonochemical synthesis with the addition of an organic ligand. For that purpose, two organic dyes are used, Phenol Red and Anthraquinone Violet. All obtained powders are characterized using XRD, SEM, EDX, FT-IR, and UV-Vis investigations. Synthesized samples showed composition and structural properties typical for sonochemically synthesized SnS2. However, investigation with the Tauc method revealed that SnS2 powder modified with Phenol Red exhibits a significant shift in value of optical bandgap to 2.56 eV, while unmodified SnS2 shows an optical bandgap value of 2.42 eV. The modification of SnS2 powder with Anthraquinone Violet was unsuccessful. The obtained nanopowders were utilized as photocatalysts in the process of Metanil Yellow degradation, revealing that SnS2 modified with Phenol Red shows about 23% better performance than the unmodified one. The mean sonochemical efficiency of the performed synthesis is also estimated as 9.35 µg/W.

Pristine, Ni- and Zn-Doped CuSe Nanoparticles: An Antimicrobial, Antioxidant, and Cytotoxicity Study

The strategy of chemical coprecipitation is implemented to synthesize nanoparticles of pristine CuSe, 5 and 10% Ni-doped CuSe, and 5 and 10% Zn-doped CuSe. All of the nanoparticles are found to be near stoichiometric by the evaluation of X-ray energy using electron dispersion spectra, and the elemental mapping shows uniform distribution. By X-ray diffraction examination, all of the nanoparticles are identified as being single-phase and having a hexagonal lattice structure. Field emission microscopy with electrons in both scanning and transmission modes affirmed the spherical configuration of the nanoparticles. The crystalline nature of the nanoparticles is confirmed by the presence of spot patterns observed in the selected area electron diffraction patterns. The observed d value matches well with the d value of the CuSe hexagonal (102) plane. Findings from dynamic light scattering reveal the size distribution of nanoparticles. The nanoparticle's stability is investigated by ζ potential measurements. Pristine and Ni-doped CuSe nanoparticles exhibit ζ potential values in the preliminary stability band of ±10 to ±30 mV, while Zn-doped nanoparticles feature moderate stability levels of ±30 to ±40 mV. The potent antimicrobial effects of synthesized nanoparticles are studied against Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Enterobacter aerogenes, and Escherichia coli bacteria. The 2,2-diphenyl-1-picrylhydrazyl scavenging test is used to investigate the nanoparticle's antioxidant activities. The results showed the highest activity for control (Vitamin C) with an IC₅₀ value of 43.6 μg/mL, while the lowest for Ni-doped CuSe nanoparticles with an IC₅₀ value of 106.2 μg/mL. Brine shrimps are utilized for in vivo cytotoxicity evaluation of the synthesized nanoparticles, which demonstrates that 10% Ni- and 10% Zn-doped CuSe nanoparticles are more damaging on brine shrimp instead on other nanoparticles with a 100% mortality rate. The lung cancer cell line of human (A549) is used to investigate in vitro cytotoxicity. The results indicate that pristine CuSe nanoparticles are more effective in the context of cytotoxicity against the A549 cell lines, possessing an IC₅₀ of 488 μg/mL. The particulars of the outcomes are explained in depth.

Sandwich-like SnS2/graphene multilayers for efficient lithium/sodium storage

2D materials have attracted extensive attention in energy storage and conversion due to their excellent electrochemical performances. Herein, we report utilization of monolayer SnS₂ sheets within SnS₂/graphene multilayers for efficient lithium and sodium storage. SnS₂/graphene multilayers are synthesized through a solution-phase direct assembly method by electrostatic interaction between monolayer SnS₂ and PDDA (polydimethyl diallyl ammonium chloride)-graphene nanosheets. It has been shown that the SnS₂/graphene multilayer electrode has a large pseudocapacity contribution for enhanced lithium and sodium storage. Typical batteries deliver a stable reversible capacity of ∼160 mA h g^-1 at 2 A g^-1 after 2000 cycles for lithium and a stable reversible capacity of ∼142 mA h g^-1 at 1 A g^-1 after 1000 cycles for sodium. The excellent electrochemical performances of SnS₂/graphene multilayers are attributed to the synergistic effect between the monolayer SnS₂ sheets and the PDDA-graphene nanosheets. The multilayer structure assembled by different monolayer nanosheets is promising for the further development of 2D materials for energy storage and conversion.

Sonochemical preparation of SnS and SnS2 nano- and micropowders and their characterization

Sonochemical production of tin(II) and tin(IV) sulfides is investigated. Different conditions of syntheses are examined: used solvent (ethanol or ethylenediamine), source of tin (SnCl₂ or SnCl₄), the molar ratio of thioacetamide to the tin source, and time of sonication. The obtained powders are characterized by the X-ray diffraction method (PXRD), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX), and the Tauc method. Raman and FT-IR measurements were performed for the obtained samples, which additionally confirmed the crystallinity and phase composition of the samples. The influence of experimental conditions on composition (is it SnS or SnS₂), morphology, and on the bandgap of obtained products is elucidated. It was found that longer sonication times favor more crystalline product. Each of bandgaps is direct and most of them show typical values - c.a. 1.3 eV for SnS and 2.4 eV for SnS₂. However, there are some exceptions. Synthesized powders show a variety of forms such as needles, flower-like, rods, random agglomerates (SnS₂) and balls (SnS). Using ethanol as a solvent led to powders of SnS₂ independently of which tin chloride is used. Sonochemistry in ethylenediamine is more diverse: this solvent protects Sn²⁺ cations from oxidation so mostly SnS is obtained, while SnCl₄ does not produce powder of SnS₂ but Sn(SO₄)₂ instead or, at a higher ratio of thioacetamide to SnCl₄, green clear mixture.

Comparative study between pure and manganese doped copper sulphide (CuS) nanoparticles

The pure CuS and Mn2+ doped CuS nanoparticles are synthesized by wet chemical route. The CuS phase and hexagonal crystal structure is confirmed by the powder X-ray diffraction and Raman analysis. The vibrational bonds present in the respective synthesized samples are confirmed by Fourier transformed infra-red spectroscopy. The spherical shapes of the nanoparticles are validated by the electron diffraction in scanning and transmission mode. The thermal analysis showed the Mn2+ doped CuS nanoparticles to be more stable than pure CuS nanoparticles. The thermal parameters determined using Coats-Redfern relation stated thermal activation energy and enthalpy change values are highest in the higher temperature range. The Seebeck coefficient variation with temperature and ambient condition Hall effect measurements showed the synthesized nanoparticles to be semiconducting and p-type in nature. The magnetic properties study by Gouy method showed the nanoparticles to be paramagnetic.

Enhanced Antifungal Activity of WS2/ZnO Nanohybrid against Candida albicans

Candida albicans forms persistent infections through the formation of biofilms that confer resistance to existing antifungal drugs. Biofilm targeting is therefore a promising strategy to combat Candida albicans infections. The WS₂/ZnO nanohybrids exhibits considerably improved antibiofilm activity and inhibited the biofilm formation by 91%, which is quite better than that for pristine WS₂, which is only 74%. The physical blend prepared by mixing WS₂ nanosheets and WS₂/ZnO in the ratio of 70:30 showed an antibiofilm activity of 58%, which was intermediate to that observed for pristine materials. The as-synthesized nanohybrid also demonstrates dose-dependent antifungal activity as calculated using the disc diffusion test. WS₂/ZnO nanohybrid shows 1.5 times higher activity compared to pristine WS₂ nanosheets suggesting that the nanohybrid materials are more effective as novel antifungal materials.

Application of sonochemically synthesized SnS and SnS2 in the electro-Fenton process: Kinetics and enhanced decolorization

SnS and SnS₂ powders were synthesized with the use of ultrasound. The indirect sonication was applied with ultrasound frequency 40 kHz and acoustic power 38 W/L. Products of syntheses were examined with PXRD, TEM, EDX, XPS, and UV-Vis (the Tauc method) investigations. The resulting microparticles were used for tip coating of copper cathodes. These electrodes were used in the degradation of model azo-dye Metanil Yellow by the electro-Fenton process. The efficiencies of degradation using copper, SnS-coated copper, and SnS₂-coated copper cathodes are compared. Kinetics of degradation of Metanil Yellow in the electro-Fenton process with the application of three different cathodes is also investigated. It was found that the degradation follows pseudo-first-order and that SnS-coated copper cathode improves the efficiency of degradation, while SnS₂-coated copper cathode decreases the efficiency of degradation.

Sn-Triggered Two-Dimensional Fast Protein Assembly with Emergent Functions

The discovery of a general strategy for organizing functional proteins into stable nanostructures with the desired dimension, shape, and function is an important focus in developing protein-based self-assembled materials, but the scalable synthesis of such materials and transfer to other substrates remain great challenges. We herein tackle this issue by creating a two-dimensional metal-protein hybrid nanofilm that is flexible and cost-effective with reliable self-recovery, stability, and multifunctionality. As it differs from traditional metal ions, we discover the capability of Sn²⁺ to initiate fast amyloid-like protein assembly (occurring in seconds) by effectively reducing the disulfide bonds of native globular proteins. The Sn²⁺-initiated lysozyme aggregation at the air/water interface leads to droplet flattening, a result never before reported in a protein system, which finally affords a multifunctional 2D Sn-doped hybrid lysozyme nanofilm with an ultralarge area (e.g., 0.2 m²) within a few minutes. The hybrid film is distinctive in its ease of coating on versatile material surfaces with endurable chemical and mechanical stability, optical transparency, and diverse end uses in antimicrobial and photo-/electrocatalytic scaffolds. Our approach provides not only insights into the effect of tin ions on macroscopic self-assembly of proteins but also a controllable and scalable synthesis of a potential biomimic framework for biomedical and biocatalytic applications.