Magnesium and silver doped CaO–Na2O–SiO2–P2O5 bioceramic nanoparticles as implant materials

Experiments on Simple Magnetic Model Systems

A simple method of synthesis of a stable bimetallic copper-silver nano-particle (CuAg-NP) was developed by successive reduction of Cu(NO3)2 and AgNO3, using hydrazine hydrate as the reducing agent and gelatin and poly-vinyl pyrrolidone (PVP) as the capping agents. The round-shaped particles were of a core-shell structure with a core of Cu0 atoms surrounded by a shell of Ag0 atoms. The size and the mol. wt. of the NPs were (100 ± 10) nm and (820 ± 157) Kd, respectively; the particles were crystalline in nature and 90% of the precursors Cu(NO3)2 and AgNO3 were converted to the NPs. The particles were more toxic to cancer cells than normal cells; the dose of the NPs (4-5 μg ml-1), that killed about 75% of the different human cancer cell lines viz, HepG2 (liver cancer), A549 (lung cancer) and AGS (stomach cancer), killed only about 22.5% of the normal cell lines viz, WRL68 (liver) and WI38 (lung). Therefore, the NP may be developed as a potent anticancer drug in future. The more detailed study on the cytotoxicity of the CuAg-NP on the HepG2 cell line revealed that the particles caused cell cycle arrest in a G2/M phase, depolarization of mitochondrial membrane potential, translocation of phosphatidylserine residues from inner to outer leaflets of cell membrane and DNA degradation; these phenomena confirmed that the NP-induced cell death was apoptotic in nature.

https://iopscience.iop.org/article/10.1088/1361-6528/aac372/pdf

A simple robust method of synthesis of copper-silver core-shell nano-particle: evaluation of its structural and chemical properties with anticancer potency.

Cryogel synthesis and solid state reactivity of NdCaCoO4

In order to identify the reasons of the complicated synthesis of NdCaCoO4 by the cryogel method, the phase formation processes during thermal processing of precursors were investigated by in-situ X-ray diffraction analysis, Rietveld refinement and energy dispersive X-ray analysis of reaction products and intermediates. Formation of NdCaCoO4 from the cryogel precursor and from the mixture of oxides and CaCO3 is observed at 1000–1100 °C. The complicated phase formation from the cryogel precursor is associated with the low reactivity of (Nd,Ca)CoO3 intermediate of the precursor thermolysis. Precipitation by NaOH/Na2CO3 instead of KOH/K2CO3 results in the reduction of NdCaCoO4 formation temperature to 800 °C. According to energy dispersive X-ray analysis, the coprecipitation of Nd, Ca and Co is accompanied by the capture of Na ions followed by the formation of NaxCoO2 phase at 600–700 °C. The enhanced reactivity of (Nd,Ca)CoO3 in this case could be attributed to the enhanced ion mobility due to the simultaneous formation of NaxCoO2, CoO and NdCaCoO4 (Hedvall effect).

Comparative analysis of NdCaCoO4 phase formation from cryogel and from solid state precursors

Copper nanoparticles localized on the surface of cotton fabric are synthesized. The structure and composition of the particles are determined by EXAFS, TEM, EPR, and XRF. The nanoparticles obtained are suggested to have a core shell structure. The study shows that copper is distributed in the fabric in the form of nanoparticles associated with fragments of macromolecules, on one hand, and in the form of nanoparticle conglomerates on the surfaces of the filaments of fibers, on the other hand. Modification of natural fabrics by copper nanoparticles results in complete destruction of Epidermophyton colonies and suppresses growth of Candida colonies, which makes it possible to apply such fabric in treatment of fungal diseases and in antiseptic treatment and healing of septic wounds.

M. I. Biryukova

Papers

Synthesis and structure of copper nanoparticles and their antiinfection properties