The development of ZnO nanoparticle-embedded graphitic-carbon nitride towards triple-negative breast cancer therapy.

The present study deals with the effects of curcumin-loaded ZnO nanoparticles (NPs) embedded in graphitic-carbon nitride (g-C3N4) sheets for breast cancer cells. The synthesis of these sheets was carried out by a simple co-precipitation method. The physicochemical and thermal properties of the composite sheets were studied using various characterization techniques. The powder X-ray diffraction and high-resolution transmission electron microscopy analyses confirmed the hexagonal wurtzite phase of the ZnO nanoparticles, which were randomly distributed on the g-C3N4 nanosheets, generating a finely bonded interface between the two components. The X-ray photoelectron spectroscopy analysis confirmed the successful formation of the g-C3N4@ZnO composite, while the thermal studies revealed the thermal stability of the composite. In addition, the drug release and kinetics studies proved that the release of curcumin was more significant under acidic conditions (pH 5) compared with neutral pH (7.4). Further, the biological assays verified the antibacterial activity (against two different cultures of E. coli and S. aureus) and anticancer activity (against MDA-MB-231 cancer cells) of the g-C3N4@ZnO/C nanocomposite. Finally, the lactate dehydrogenase activity assay presented the cytotoxic assessment of the nanocomposite based on its cytoplasmic activity and the extent of enzymes released from the damaged cells.

Biosynthesised Silver Nanoparticles Loading onto Biphasic Calcium Phosphate for Antibacterial and Bone Tissue Engineering Applications.

Biphasic calcium phosphate (BCP) serves as one of the substitutes for bone as it consists of an intimate mixture of beta-tricalcium phosphate (ß-TCP) and hydroxyapatite (HAP) in different ratios. BCP, because of its inbuilt properties such as osteoconductivity, biocompatibility, and biostability in several clinical models serves as a bone substituent for orthopedic applications. Therefore, the present study aimed to assess the effectiveness of silver (Ag) nanoparticles (NPs) combined with BCP composites for the orthopedic sector of bone tissue regeneration and growth. In this regard, we first synthesized Ag-BCP microclusters by the double-emulsion method and then characterized the composite for various physicochemical properties, including the crystallinity and crystal structure, bonding and functionality, porosity, morphology, surface charges, topography, and thermal stability. In addition, the antibacterial activity of Ag-BCP was tested against gram-positive and gram-negative microorganisms such as Staphylococcus aureus, Candida albicans, and Escherichia coli. Finally, the cytocompatibility of Ag-BCP was confirmed against the fibroblast cells in vitro.

Microwave-assisted green synthesis of multi-functional carbon quantum dots as efficient fluorescence sensor for ultra-trace level monitoring of ammonia in environmental water.

This study reports a facile green preparation of self-assembled multi-functional carbon quantum dots (CQDs) via direct pyrolysis technique coupled with microwave-assisted synthesis using Ziziphus Mauritiana stone biomass (as a bio-resource precursor). The synthesized multi-functional CQDs was characterized using FT-IR, XRD, XPS, TEM, and fluorescence spectroscopy techniques. The results exhibit that the prepared CQDs are spherical-shaped with an average diameter of 2-4 nm and showed bright bluish-green emissions property with stable dispersion and high photostability in the aqueous medium. Furthermore, the emission properties of CQDs were examined by quenched with ammonia (NH3) and other molecules in aqueous media. Results indicated that the developed CQDs showed effective fluorescent for the selective and sensitive detection (sensor) of NH3 with a detection limit of 10 nM. Thus, the presented procedure is a simple, low-cost, efficient, chemical-free synthesis of CQDs and can be applied as selective and sensitive (sensor) monitoring of NH3 concentration in aquatic environmental samples.

Novel pure α-, ß-, and mixed-phase α/ß-Bi2O3 photocatalysts for enhanced organic dye degradation under both visible light and solar irradiation.

Combining the pure α- and ß-phases of bismuth oxide enhances its photocatalytic activity under both visible and solar irradiation. α-Bi2O3, ß-Bi2O3, and α/ß-Bi2O3 were synthesized by a solvothermal calcination method. The structural, optical, and morphological properties of the as-synthesized catalysts were analyzed using XRD, UV-DRS, XPS, SEM, TEM, and PL. The bandgaps of α/ß-Bi2O3, α-Bi2O3, and ß-Bi2O3 were calculated to be 2.59, 2.73, and 2.34 eV, respectively. The photocatalytic activities of the catalysts under visible and solar irradiation were examined by the degradation of carcinogenic reactive blue 198 and reactive black 5 dyes. The kinetic plots of the degradation reactions followed pseudo-first-order kinetics. α/ß-Bi2O3 exhibited higher photocatalytic activity (∼99%) than α-Bi2O3 and ß-Bi2O3 under visible and solar irradiation. The TOC and COD results confirmed the maximum degradation ability of α/ß-Bi2O3, and the decolorization percentage remained above 90%, even after five cycles under visible irradiation. The photocatalytic dye degradation mechanism employed by α/ß-Bi2O3 was proposed based on active species trapping experiments.

Surfactant Assisted Hydroxyapatite Nanoparticles: Drug Loading and In Vitro Leaching Kinetics and Antimicrobial Properties.

In the present investigation, extremely fine Hydroxyapatite (HAP) powder was prepared through chemical precipitation technique under the influence of a nonionic surfactant (Brij 35-Polyoxyethylene lauryl ether). The samples were sintered at 800 °C to obtain highly pure HAP phase. The functional group present in the HAP powder was confirmed by using Fourier transform infra-red (FTIR) spectroscopy. The change in Phase transformation, the crystallite size and the percentage of crystallinity of the synthesized sample were studied by X-ray diffractometer technique. The Field Emission Scanning Electron Microscope (FESEM) and High-resolution transmission electron microscopy (HRTEM) were used for the structural analysis of porous rod-shaped HAP crystal. Further, drug loading and In Vitro leaching kinetics were conducted for antibiotics-ciproflaxin (CPF). Antimicrobial activity against S. aureus (Gram-positive bacterium) and E. coli (Gram-negative bacterium) was executed for pure HAP as well as for drug loaded HAP.

New core-shell hydroxyapatite/Gum-Acacia nanocomposites for drug delivery and tissue engineering applications.

Core-shell hydroxyapatite (HAP) - gum acacia (GA) nanocomposite, in which the HAP acts as a core while the GA serves as a shell, was synthesized by precipitation techniqueusing Ca(NO3)2.4H2O and NH4H2PO4as precursors for Ca and P, respectively. The crystallite size and morphology of the synthesized core-shell HAP-GA nanocomposite was evaluated by X-ray diffraction measurement and transmission electron microscopy. The crystallite size of GA-HAP nanocomposite is markedly decreased from 89 nm to 63 nm when the concentration of GA in the reaction mixture is increased from 0 to 10%. Transmission electron micrographs confirm encapsulation of GA over the HAP particles, leading to the formation of GA shell-HAP core assembly, which is quite evident for 10% GA-HAP composites. The nature of functional groups present in HAP was identified using FT-IR and Raman spectroscopies while its chemical composition was analyzed by energy dispersive X-ray analysis. The Ca/P ratio of the synthesized HAP's was found to be 1.67. The elemental composition of the HAP samples was evaluated by X-ray photoelectron spectroscopy. The peaks at binding energies 286.5 and 289.3 eV of C 1S and the peaks at 530.6 eV and 532.1 eV of the O 1S spectra further substantiate encapsulation of GA over the HAP particles, resulting in the formation of GA-HAP nanocomposite. Pellet samples of HAP were immersed in simulated body fluid to ascertain their bioactivity using scanning electron micrographs. The drug, naringenin, was loaded within the core of HAP by pellet pressing method. The drug-loaded core-shell HAP composites were subjected to microbial studies, hemolytic studies and MTT assay to assess their biocompatibility.

A Facile Method to Modify the Characteristics and Corrosion Behavior of 304 Stainless Steel by Surface Nanostructuring toward Biomedical Applications.

The study addresses how surface nanostructuring of AISI 304 stainless steel (SS) by surface mechanical attrition treatment (SMAT) influences its characteristic properties and corrosion behavior in Ringer's solution. SMAT of 304 SS induced plastic deformation, enabled surface nanocrystallization, refined the grain size, transformed the austenite phase to strain induced α'-martensite phase, increased the surface roughness, induced defects/dislocations, imparted compressive residual stresses at the surface, decreased the contact angle, and increased surface energy. The change in properties of 304 SS following treatment using 5 and 8 mm ⌀ balls for 15, 30, 45, and 60 min has caused a deleterious influence on its corrosion resistance in Ringer's solution, while an improvement in corrosion behavior is observed for those treated using 2 mm ⌀ balls. The increase in surface roughness, transformation of the austenite to α'-martensite phase, a higher extent of deformation, and the presence of larger number of defects/dislocations are main factors responsible for the lower corrosion resistance observed for 304 SS treated using 5 and 8 mm ⌀ balls in Ringer's solution. In spite of having these attributes with a relatively lower extent, 304 SS treated using 2 mm ⌀ balls offered a better corrosion resistance and exhibits a better passivity. For those treated using 2 mm ⌀ balls, the ability of the nanocrystalline surface to promote passivation outweighs the deleterious influences caused by the limited amount of deformation and defects/dislocations. Based on the findings of this study, it is recommend that SMAT of 304 SS using 2 mm ⌀ balls for 15-30 min is the optimum condition to achieve the suitable surface profile, surface characteristics with better corrosion resistance.