The olivine type LiFePO4 is synthesized via a simple and inexpensive route by aqueous co-precipitation of an Fe(II) precursor material in molten stearic acid and subsequent heat treatment at different temperatures. Stearic acid serves as both chelating agent and carbonaceous material. The obtained composites with carbon are characterized by X-ray powder diffraction, field emission scanning electron microscopy, and Mössbauer spectroscopy. Electrochemical characteristics of the composites are evaluated by using galvanostatic charge/discharge tests. The powder obtained at 700 °C delivers discharge capacity of 160 mAh g−1, quite near the theoretical value

In an earlier study we demonstrated that hydroxyapatite nanoparticles coated with chitosan-poly(d,l)-lactide-co-glycolide (HAp/Ch-PLGA) target lungs following their intravenous injection into mice. In this study we utilize an emulsification process and freeze drying to load the composite HAp/Ch-PLGA particles with 17β-hydroxy-17α-picolyl-androst-5-en-3β-yl-acetate (A), a chemotherapeutic derivative of androstane and a novel compound with a selective anticancer activity against lung cancer cells. 1H NMR and 13C NMR techniques confirmed the intact structure of the derivative A following its entrapment within HAp/Ch-PLGA particles. The thermogravimetric and differential thermal analyses coupled with mass spectrometry were used to assess the thermal degradation products and properties of A-loaded HAp/Ch-PLGA. The loading efficiency, as indicated by the comparison of enthalpies of phase transitions in pure A and A-loaded HAp/Ch-PLGA, equaled 7.47wt.%. The release of A from HAp/Ch-PLGA was sustained, neither exhibiting a burst release nor plateauing after three weeks. Atomic force microscopy and particle size distribution analyses were used to confirm that the particles were spherical with a uniform size distribution of d50=168nm. In vitro cytotoxicity testing of A-loaded HAp/Ch-PLGA using MTT and trypan blue dye exclusion assays demonstrated that the particles were cytotoxic to the A549 human lung carcinoma cell line (46±2%), while simultaneously preserving high viability (83±3%) of regular MRC5 human lung fibroblasts and causing no harm to primary mouse lung fibroblasts. In conclusion, composite A-loaded HAp/Ch-PLGA particles could be seen as promising drug delivery platforms for selective cancer therapies, targeting malignant cells for destruction, while having a significantly lesser cytotoxic effect on the healthy cells.

Hydrogels have emerged as versatile platforms for controlled and sustained drug delivery due to their high biocompatibility, tunable mechanical properties, and ability to mimic the natural extracellular matrix. Incorporating functional nanomaterials into hydrogel networks introduces additional structural and functional complexity, enabling stimuli-responsive release, enhanced bioactivity, and synergistic therapeutic effects. This review provides a comprehensive overview of recent advances in the design, fabrication, and characterization of nanomaterial-integrated hydrogels for biomedical applications. Emphasis is placed on nanoparticle synthesis, functionalization strategies, incorporation into hydrogel matrices, physicochemical characterization, and biological aspects, including cytotoxicity, genotoxicity, antioxidative, and antibacterial effects. Emerging approaches for performance optimization, such as preliminary data-driven strategies and machine learning-based modeling, are also discussed. Special attention is given to smart and stimuli-responsive hydrogels and their potential biomedical applications.

Olivine-type LiFePO4 composite powders with carbon were synthesized by freeze drying and subsequent thermal annealing. The main purpose of the research is to explore how various dicarboxylic acids as carbon sources influence the electrochemical properties of the resulting composites. Three dicarboxylic acids (oxalic, malonic, and adipic) were used as a carbon source. The synthesis was followed by X-ray powder diffraction, scanning electron microscopy, particle-size analysis, and electrochemical experiments. It is shown that the amount of the in situ formed carbon depends on the thermal behaviour of the acids in inert atmosphere rather than on their carbon content. Cyclic voltammetry experiments and galvanostatic cycling illustrate the behaviour of different powders: the powder obtained with oxalic acid yields the highest discharge capacity at small currents, while the one obtained with adipic acid shows better high-current response. Malonic acid has turned out to be a poor carbon source and it consequently yields powder with poor electrochemical performance

Lithium iron phosphate powders were obtained by solvothermal treatments of quaternary emulsions Triton X-100/cyclohexane/n-hexanol/water at low temperature (180 °C), with or without stirring. Such synthesis conditions allowed for fast crystallization of pure olivine-type LiFePO4 powder, evidenced by the X-ray powder diffraction measurements and energy dispersive spectroscopy. It has been found that stirring drastically changes the morphology of LiFePO4 particles, causing a preferential crystal orientation. Also, a great difference in the morphology was demonstrated by field emission scanning electron microscopy. The powder obtained after only half an hour of the dynamic solvothermal treatment, without additional post annealing, and without carbon coating, was electrochemically active, showing the discharge capacity of 115 mAh g− 1

Multidrug-resistant bacterial strains represent an emerging global health threat and a great obstacle for bone tissue engineering. One of the major components of the extracellular matrix of the bone is a collagen protein, while selenium is an element that has antimicrobial potential, and is also important for bone metabolism and bone health. Here we represent the incorporation of selenium nanoparticles (SeNPs) synthesized by the green chemical reduction method into collagen gels to produce a composite material, collagen/SeNPs, with antimicrobial properties. The samples were comprehensively characterized by zeta potential measurements, dynamic light scattering inductively coupled plasma-mass spectrometry (ICP-MS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), optical microscopy, field-emission scanning electron microscopy (FE-SEM), and differential scanning calorimetry The cytotoxicity of the SeNPS, as well as collagen/SeNPs, was tested on the MRC-5 cells. It was revealed that collagen/SeNPS expressed a lower cytotoxic effect. Collagen/SeNPs showed significant antibacterial activity against all tested Gram-positive strains, the major causative agents of orthopedic infections as well as Candida albicans. Furthermore, three-dimensional β-tricalcium phosphate (3D-TCP) scaffolds were fabricated by a well-established 3D printing (lithography) method, and afterward preliminary coated by newly-synthesized SeNPs or collagen/SeNPs. In addition, uncoated 3D-TCP scaffolds as well as coated by collagen/SeNPs were subjected to biofilm formation. The production of Staphylococcus aureus biofilm on coated scaffolds by collagen/SeNPs was significantly reduced compared to the uncoated ones.