Hydrothermal synthesis and photocatalytic application of ZnS-Ag composites based on biomass-derived carbon aerogel for the visible light degradation of methylene blue.

A facile and cost-effective hydrothermal followed by precipitation method is employed to synthesize visible light-driven ZnS-Ag ternary composites supported on carbon aerogel (CA). Extensive studies were conducted on the structural, morphological, and optical properties, confirming the successful formation of ternary nanocomposites. The obtained results evidently demonstrate the successful loading of ZnS and Ag onto the surface of the CA. High-resolution transmission electron microscopy analysis revealed that ZnS and Ag nanoparticles (AgNPs) were uniformly distributed on the surface of the CA with an average diameter of 18 nm. The biomass-derived CA, containing a hierarchical porous nano-architecture and an abundant number of -NH2 functional groups on the surface, can greatly prevent the agglomeration, stability and reduce particle size. Brunauer-Emmett-Teller analysis results indicated specific surface areas of 4.62 m2 g-1 for the CA, 48.50 m2 g-1 for the CA/ZnS composite, and 62.62 m2 g-1 for the CA/ZnS-Ag composite. These values demonstrate an increase in surface area upon the incorporation of ZnS and Ag into the CA matrix. Under visible light irradiation, the synthesized CA/ZnS-Ag composites displayed remarkably improved photodegradation efficiency of methylene blue (MB). Among the tested samples, the CA/ZnS-Ag composites exhibited the highest percentage of photodegradation efficiency, surpassing ZnS, CA, and CA/ZnS. The obtained percentages of degradation efficiency for CA, ZnS, CA/ZnS, and CA/ZnS-Ag composites were determined as 26.60%, 52.12%, 68.39%, and 98.64%, respectively. These results highlight the superior photocatalytic performance of the CA/ZnS-Ag composites in the degradation of MB under visible light conditions. The superior efficiency of the CA/ZnS-Ag composite can be attributed to multiple factors, including its elevated specific surface area, inhibition of electron-hole pair recombination, and enhanced photon absorption within the visible light spectrum. The CA/ZnS-Ag composites displayed consistent efficiency over multiple cycles, confirming their stable performance, reusability, and enduring durability, thereby showcasing the robust nature of this composite material.

Exploring copper (II) porphyrin complexes and their derivatives for electrochemical analysis and biological assessment in the study of breast cancer (MCF-7) cell lines.

In this study, several derivatives of tetraphenylporphyrin were synthesized, each with unique meso-substituent groups including phenyl, methoxyphenyl, butyloxyphenyl, octyloxyphenyl, and dectyloxyphenyl. Additionally, their corresponding copper complexes were prepared and thoroughly characterized. The structural confirmation of all compounds was established through CHN elemental analysis, mass spectrometry, and FT-IR spectroscopy. As the number of carbon atoms in the alkyl long-chain increased, a slight red shift in the electronic absorption band was observed, which was attributed to the electronic influence of the alkyl group. DFT analysis indicated that electron density predominantly localized on the porphyrin ring of both the metal free porphyrins and copper (II) porphyrin complexes, with relatively low electron density in the p orbital of the meso-aryl long-chain substituent group. EPR spectroscopy of the Copper (II) ion complexes revealed signals, indicating their paramagnetic properties. Additionally, the Copper (II) tetraphenylporphyrin (CuTPP) complexes displayed two reversible oxidation peaks at +0.97 V and +1.35 V, whereas other derivatives exhibited lower oxidation potentials. The cytotoxicity of these compounds against MCF-7 cell lines was assessed using MTT assay, revealing cytotoxic effects in all cases. Among them, Copper (II) tetrakis (4-methyloxyphenyl)porphyrin (CuTOMPP) demonstrated the highest potential, with an IC50 value of 32.07 µg/mL.

Effects of Oral Cavity Stem Cell Sources and Serum-Free Cell Culture on Hydrogel Encapsulation of Mesenchymal Stem Cells for Bone Regeneration: An In Vitro Investigation.

INTRODUCTION: To develop a stem cell delivery model and improve the safety of stem cell transplantation for bone regeneration, this study aimed to determine the effects of stem cell sources, serum-free cell culture, and hydrogel cell encapsulation on the growth and osteogenic differentiation of mesenchymal stem cells (MSCs) from the oral cavity. METHODS: The study groups were categorized according to stem cell sources into buccal fat pad adipose (hBFP-ADSCs) (Groups 1, 4, and 7), periodontal ligament (hPDLSCs) (Groups 2, 5, and 8), and dental pulp-derived stem cells (hDPSCs) (Groups 3, 6, and 9). MSCs from each source were isolated and expanded in three types of sera: fetal bovine serum (FBS) (Groups 1-3), human serum (HS) (Groups 4-6), and synthetic serum (SS) (StemPro™ MSC SFM) (Groups 7-9) for monolayer (m) and hydrogel cell encapsulation cultures (e). Following this, the morphology, expression of MSC cell surface antigens, growth, and osteogenic differentiation potential of the MSCs, and the expression of adhesion molecules were analyzed and compared. RESULTS: SS decreased variations in the morphology and expression levels of cell surface antigens of MSCs from three cell sources (Groups 7m-9m). The levels of osteoblastic differentiation of the hPDLSCs and hBFP-ADSCs were increased in SS (Groups 8m and 7m) and the cell encapsulation model (Groups 1e, 4e, 7e-9e), but the promoting effects of SS were decreased in a cell encapsulation model (Groups 7e-9e). The expression levels of the alpha v beta 3 (ITG-αVß3) and beta 1 (ITG-ß1) integrins in the encapsulated cells in FBS (Group 1e) were higher than those in the SS (Group 7e). CONCLUSIONS: Human PDLSCs and BFP-ADSCs were the optimum stem cell source for stem cell encapsulation by using nanohydroxyapatite-calcium carbonate microcapsule-chitosan/collagen hydrogel in serum-free conditions.

Eggshell-Derived Copper Calcium Hydroxy Double Salts and Their Activity for Treatment of Highly Polluted Wastewater.

By using methyl orange (MO) removal as a model reaction, the best temperatures for processing eggshells are 750 °C and above to obtain biobased CaO materials, a raw material for producing CuCa hydroxy double salt (HDS) materials with high efficiency in treatments of highly polluted wastewater (the initial concentration of MO is 500 ppm). Characterization techniques employed in this study include power X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, nitrogen adsorption-desorption analysis, and the colorimetric method, as well as energy-dispersive X-ray, infrared-, and electron spin resonance spectroscopies. Complete MO removal and high chemical oxygen demand (COD) efficiencies (>90%) can be achieved after 3 min treatments of the aqueous MO with the calcined eggshell-derived CuCa HDS materials. The spent, deactivated HDS materials can be regenerated by an acid wash method. The activity of CuCa HDS materials in MO removal is unaffected by eggshell sources, implying that sorting steps may be unnecessary when eggshell food waste (duck, quail, and hen eggshells) is collected to produce biobased CaO. The findings of this study demonstrated that eggshells can be used in place of limestone and could be a more sustainable, renewable, and cost-effective source for material development and other applications.

Nitrogen-doped carbon dots: Recent developments in its fluorescent sensor applications.

Doped carbon dots have attracted great attention from researchers across disciplines because of their unique characteristics, such as their low toxicity, physiochemical stability, photostability, and outstanding biocompatibility. Nitrogen is one of the most commonly used elements for doping because of its sizeable atomic radius, strong electronegativity, abundance, and availability of electrons. This distinguishes them from other atoms and allows them to perform distinctive roles in various applications. Here, we have reviewed the most current breakthroughs in nitrogen-doped CDs (N-CDs) for fluorescent sensor applications in the last five years. The first section of the article addresses several synthetic and sustainable ways of making N-CDs. Next, we briefly reviewed the fluorescent features of N-CDs and their sensing mechanism. Furthermore, we have thoroughly reviewed their fluorescent sensor applications as sensors for cations, anions, small molecules, enzymes, antibiotics, pathogens, explosives, and pesticides. Finally, we have discussed the N-CDs' potential future as primary research and how that may be used. We hope that this study will contribute to a better understanding of the principles of N-CDs and the sensory applications that they can serve.

In-situ development of boron doped g-C3N4 supported SBA-15 nanocomposites for photocatalytic degradation of tetracycline.

In this study, versatile boron-doped graphitic carbon nitride (gCN) incorporated mesoporous SBA-15 (BGS) composite materials were prepared by thermal polycondensation method using boric acid & melamine as a B-gCN source material and SBA-15 as mesoporous support. The prepared BGS composites are utilized sustainably using solar light as the energy source for the continuous flow of photodegradation of tetracycline (TC) antibiotics. This work highlights that the photocatalysts preparation was carried out with an eco-friendly strategy, solvent-free and without additional reagents. To alter the amount of boron quantity (0.124 g, 0.248 g, and 0.49 g) have to prepare three different composites using a similar procedure, the obtained composites viz., BGS-1, BGS-2 and BGS-3, respectively. The physicochemical property of the prepared composites was investigated by X-ray diffractometry, Fourier-transform infrared spectroscopy, Raman, Diffraction reflectance spectra, Photoluminescence, Brunauer-Emmett-Teller and transmission electron microscopy (TEM). The results shows that 0.24 g boron- loaded BGS composites degrade TC up to 93.74%, which is much higher than the rest of the catalyst. The addition of mesoporous SBA-15 incresed the specific surface area of the g-CN, and heteroatom of boron increased the interplanar stracking distance of g-CN, enlarged the optical absorption range, reducing the energy bandgap and enhanced the photocatalytic activity of TC. Additionally, the stability and recycling efficiency of the representative photocatalysts viz., BGS-2 was observed to be good even at the fifth cycle. The photocatalytic process using the BGS composites demonstrated to be capable candidate for the removal of tetracycline biowaste from aquesous media.

Effects of Calcium Carbonate Microcapsules and Nanohydroxyapatite on Properties of Thermosensitive Chitosan/Collagen Hydrogels.

Thermosensitive chitosan/collagen hydrogels are osteoconductive and injectable materials. In this study, we aimed to improve these properties by adjusting the ratio of nanohydroxyapatite particles to calcium carbonate microcapsules in a ß-glycerophosphate-crosslinked chitosan/collagen hydrogel. Two hydrogel systems with 2% and 5% nanohydroxyapatite particles were studied, each of which had varying microcapsule content (i.e., 0%, 1%, 2%, and 5%). Quercetin-incorporated calcium carbonate microcapsules were prepared. Calcium carbonate microcapsules and nanohydroxyapatite particles were then added to the hydrogel according to the composition of the studied system. The properties of the hydrogels, including cytotoxicity and biocompatibility, were investigated in mice. The calcium carbonate microcapsules were 2-6 µm in size, spherical, with rough and nanoporous surfaces, and thus exhibited a burst release of impregnated quercetin. The 5% nanohydroxyapatite system is a solid particulate gel that supports homogeneous distribution of microcapsules in the three-dimensional matrix of the hydrogels. Calcium carbonate microcapsules increased the mechanical and physical strength, viscoelasticity, and physical stability of the nanohydroxyapatite hydrogels while decreasing their porosity, swelling, and degradation rates. The calcium carbonate microcapsules-nanohydroxyapatite hydrogels were noncytotoxic and biocompatible. The properties of the hydrogel can be tailored by adjusting the ratio of calcium carbonate microcapsules to the nanohydroxyapatite particles. The 1% calcium carbonate microcapsules containing 5% nanohydroxyapatite particle-chitosan/collagen hydrogel exhibited mechanical and physical strength, permeability, and prolonged release profiles of quercetin, which were superior to those of the other studied systems and were optimal for promoting bone regeneration and delivering natural flavonoids.

Characteristics and biologic effects of thermosensitive quercetin-chitosan/collagen hydrogel on human periodontal ligament stem cells.

Thermosensitive hydrogels could function as scaffolds and delivery vehicle of natural flavonoids. The current study aimed to investigate effects of chitosan/collagen ratios on properties of thermosensitive beta-glycerophosphate (bGP) chitosan/collagen hydrogels as delivery vehicle of quercetin and then examined effects of quercetin-hydrogels on growth and cell viability of human periodontal ligament stem cells (hPDLSCs). Microstructure and physical, mechanical and antioxidant properties and quercetin release profiles of the hydrogels were investigated. Fourier transform infrared spectroscopy and X-ray powder diffraction analyses were performed to examine gelation process of the hydrogels. Antioxidant assays were conducted to measure antioxidant capacity of quercetin-hydrogels. It was found that bGP-chitosan/collagen hydrogels exhibited porous structures with interconnected pore architecture and could sustain quercetin release. Chitosan content improved well defined porous structure, increased porosity of the hydrogels and decreased releasing rate of quercetin from the hydrogels. The quercetin-bGP-2:1 (wt/wt) chitosan/collagen hydrogels exhibited antioxidant capacity and were able to promote growth of hPDLSCs in a dose dependent manner. In conclusion, the thermosensitive quercetin-bGP-2:1 (wt/wt) chitosan/collagen hydrogel demonstrated optimal properties of scaffolds for bone tissue engineering and sustained release of natural flavonoids. Incorporating quercetin in the chitosan/collagen hydrogel enhanced bioactive microenvironment that supported stem cell encapsulation.

Effects of beta-tricalcium phosphate nanoparticles on the properties of a thermosensitive chitosan/collagen hydrogel and controlled release of quercetin.

In the present study, an inorganic matrix of beta-tricalcium phosphate (bTCP) nanoparticles and quercetin was incorporated into an organic matrix of 2:1 (w/w) chitosan/collagen composite to fabricate thermosensitive bTCP-chitosan/collagen-quercetin hydrogels. A sol-gel transition of the hydrogels was stimulated by beta-glycerophosphate (bGP) and temperature changes at physiological temperature and pH levels. Thereafter, the effects of 1%-3% (w/v) bTCP on properties of the bTCP-bGP-2:1 (w/w) chitosan/collagen hydrogels were investigated. Notably, the incorporation of 1%-3% (w/v) bTCP in the hydrogels did not interfere with the gelation process and time of the hydrogels at physiological temperature and pH levels. The bTCP-hydrogels exhibited a porous structure, interconnecting pore architecture, and median pore size of 100-200 µm. The incorporation of 3% bTCP increased the mechanical strength but decreased the swelling and degradation rates, pore size, permeability, and quercetin release rate of the hydrogels. The hydrogels were noncytotoxic and able to support cell encapsulation. A sustained quercetin release profile of the 3% bTCP-hydrogel further suggested the applicability of the hydrogel as a delivery vehicle of natural flavonoids for bone regeneration.

Transesterification of soybean oil using bovine bone waste as new catalyst.

Calcined bovine bone waste was employed to catalyze the transesterification reaction between soybean oil and methanol. The influence of various conditions on the efficiency of the transesterification was studied i.e. type of reactor, temperature, catalyst loading and methanol/oil ratio. The optimum yield of methyl ester (97%) was obtained by performing the closed-system transesterification at 65 °C for 3 h with catalyst loading of 8% wt and 6:1 methanol to oil ratio, using bone calcined at 750 °C. Calcination of the commercial bovine bone at 650 °C and above results in conversion of the calcium carbonate component to calcium oxide, with the major component being crystalline hydroxyapetite. Calcium oxide is believed to be responsible for the catalytic activity of the material. The reusability, low cost and low catalyst loading required (4% wt) may make bovine bone an attractive alternative to existing transesterification catalyst systems.

Thiolates vs. halides as pi-donors: the redox-active alkyne complexes [M(SR)L(eta-R'C[triple bond]CR')L'] {M = Mo or W, L = CO or P(OMe)(3), L' = eta-C(5)H(5) and Tp'}.

The cyclic voltammograms of the alkyne complexes [M(SR)L(eta-R'C[triple bond, length as m-dash]CR')(eta-C(5)H(5))] (M = Mo or W, R = Me or Ph, R' = Me or Ph) show two oxidation processes. Both are irreversible for the stereochemically rigid carbonyls (L = CO) but the first is reversible for the fluxional phosphites {L = P(OMe)(3)}; the paramagnetic monocations [M(SPh){P(OMe)(3)}(eta-MeC[triple bond, length as m-dash]CMe)(eta-C(5)H(5))](+) were detected by ESR spectroscopy after in situ chemical one-electron oxidation. By contrast, the hydrotris(pyrazolyl)borate analogues [W(SR)(CO)(eta-PhC[triple bond, length as m-dash]CPh)Tp'] {R = Me or Ph, Tp' = hydrotris(3,5-dimethylpyrazolyl)borate} are oxidised in two reversible steps to the corresponding mono- and dications; the redox pair [W(SPh)(CO)(eta-PhC[triple bond, length as m-dash]CPh)Tp'](z) (z = 0 and 1+) has been structurally characterised. A comparison of the redox potentials for the oxidation of [W(SR)(CO)(eta-PhC[triple bond, length as m-dash]CPh)Tp'] with those of the halide analogues [WX(CO)(eta-PhC[triple bond, length as m-dash]CPh)Tp'] suggests that the factors which give rise to the inverse halide order for the latter may not operate for the thiolates, which appear to be the better pi-donors in all three redox states [WL(CO)(eta-PhC[triple bond, length as m-dash]CPh)Tp'](z) (L = halide or thiolate, z = 0, 1+ and 2+).

Structural consequences of the one-electron reduction of d4 [Mo(CO)2(eta-PhC[triple bond]CPh)Tp']+ and the electronic structure of the d5 radicals [M(CO)L(eta-MeC[triple bond]CMe)Tp'] {L = CO and P(OCH2)3CEt}.

Reduction of [M(CO)2(eta-RC[triple bond]CR')Tp']X {Tp' = hydrotris(3,5-dimethylpyrazolyl)borate, M = Mo, X = [PF6]-, R = R' = Ph, C6H4OMe-4 or Me; R = Ph, R' = H; M = W, X = [BF4]-, R = R' = Ph or Me; R = Ph, R' = H} with [Co(eta-C5H5)2] gave paramagnetic [M(CO)2(eta-RC[triple bond]CR')Tp'], characterised by IR and ESR spectroscopy. X-Ray structural studies on the redox pair [Mo(CO)2(eta-PhC[triple bond]CPh)Tp'] and [Mo(CO)2(eta-PhC[triple bond]CPh)Tp'][PF6] showed that oxidation is accompanied by a lengthening of the C[triple bond]C bond and shortening of the Mo-C(alkyne) bonds, consistent with removal of an electron from an orbital antibonding with respect to the Mo-alkyne bond, and with conversion of the alkyne from a three- to a four-electron donor. Reduction of [Mo(CO)(NCMe)(eta-MeC[triple bond]CMe)Tp'][PF6] with [Co(eta-C5H5)2] in CH2Cl2 gives [MoCl(CO)(eta-MeC[triple bond]CMe)Tp'], via nitrile substitution in [Mo(CO)(NCMe)(eta-MeC[triple bond]CMe)Tp'], whereas a similar reaction with [M(CO){P(OCH2)3CEt}(eta-MeC[triple bond]CMe)Tp']+ (M = Mo or W) gives the phosphite-containing radicals [M(CO){P(OCH2)3CEt}(eta-MeC[triple bond]CMe)Tp']. ESR spectroscopic studies and DFT calculations on [M(CO)L(eta-MeC[triple bond]CMe)Tp'] {M = Mo or W, L = CO or P(OCH2)3CEt} show the SOMO of the neutral d5 species (the LUMO of the d4 cations) to be largely d(yz) in character although much more delocalised in the W complexes. Non-coincidence effects between the g and metal hyperfine matrices in the Mo spectra indicate hybridisation of the metal d-orbitals in the SOMO, consistent with a rotation of the coordinated alkyne about the M-C2 axis.

A neutral organometallic fluoro complex can be a good ligand.

The reaction of the complex [Mo(OTf)(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)] (1) (OTf = trifluoromethylsulfonate; phen = 1,10-phenanthroline) with tetrabutylammonium fluoride trihydrate afforded the fluoride complex [MoF(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)] (2). The IR spectrum and the oxidation potential of 2 reflect the fact that its metal center is more electron-rich than that of the chloro analogue [MoCl(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)]. Compound 2 reacted with 1 affording the homobinuclear complex [[Mo(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)](2)(mu-F)][OTf] (3), with a fluoride bridge. Compound 2 also reacts with the species generated in situ by triflate abstraction from [M(OTf)(CO)(3)('N-N')] (M = Mn, Re; 'N-N' = 2,2'-bipyridine (bipy), phen) using NaBAr'(4) (Ar' = 3,5-bis(trifluoromethyl)phenyl), affording the heterobinuclear complexes [[Mo(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)](mu-F)[M(CO)(3)('N--N')]][BAr'(4)] (M = Mn, 'N-N' = bipy (4); M = Re, 'N-N' = phen (5)). All new compounds have been characterized by spectroscopic methods (IR and NMR) and, in the case of 1, 2, 3, and 4, also by means of X-ray diffraction analysis.