Katarzyna Zawisza

An up-converting HAP@β-TCP nanocomposite activated with Er3+/Yb3+ ion pairs for bio-related applications

A HAP@β-TCP nanocomposite doped with Er3+/Yb3+ ion pairs was prepared using Pechini’s technique. The structural properties and morphology of the particles were studied by means of XRD, TEM, and DLS techniques. The cytotoxicity of the developed product was tested on canine osteosarcoma (D17) and murine macrophage (J774.E) cells. Determination of metronidazole release from the HAP@β-TCP nanocomposite was carried out using dynamic dialysis and ultracentrifugation techniques. Thorough analysis of the up-conversion properties of the prepared system was carried out, showing that the GRR depends strongly on the sample temperature induced by the optical density of excitation, and the particle size. Relatively short decay times and the behaviour of the GRR pointed towards the enhanced contribution of non-radiative processes feeding the red emission.

Multifunctional nanocrystalline calcium phosphates loaded with Tetracycline antibiotic combined with human adipose derived mesenchymal stromal stem cells (hASCs).

Osteoconductive drug delivery system composed of nanocrystalline calcium phosphates (Ca10(PO4)6(OH)2/β-Ca3(PO4)2) co-doped with Yb(3+)/Er(3+) ions loaded with Tetracycline antibiotic (TC) was developed. Their effect on human adipose derived mesenchymal stromal stem cells (hASCs) as a potential reconstructive biomaterial for bone tissue regeneration was studied. The XRD and TEM measurements were used in order to determine the crystal structure and morphology of the final products. The characteristics of nanocomposites with the TC and hASCs as potential regenerative materials as well as the antimicrobial activity of the nanoparticles against: Staphylococcus aureus ATCC 25923 as a model of the Gram-positive bacteria, Escherichia coli ATCC 8739 of the Gram-negative bacteria, were shown. These combinations can be a promising material for theranostic due to its regenerative, antimicrobial and fluorescent properties.

Effect of lithium substitution on the charge compensation, structural and luminescence properties of nanocrystalline Ca10(PO4)6F2 activated with Eu3+ ions

Eu3+ and Li+ ion co-doped fluorapatite (Ca10(PO4)6F2) nanocrystals were fabricated using a microwave stimulated hydrothermal technique followed by heat treatment at 500 °C. The concentration of Eu3+ ions was set to be 1 mol% and that of the Li+ ions was in the range of 0.5–5 mol% to investigate the site occupancy preference and charge compensation co-doping. The structural and morphological properties of the obtained samples were determined by using XRD (X-ray powder diffraction) and TEM (transmission electron microscopy) techniques as well as IR (infrared) and micro-Raman spectroscopy. The particle size was verified and calculated by the Rietveld method being in the range of 70–95 nm. The luminescence properties (the emission, excitation spectra and emission kinetics) of the Eu3+ ion-doped fluorapatite depending on the co-dopant (Li+ ions) were recorded. Significantly, fluorescence quenching by OH− groups was eliminated by F- ions and the luminescence intensity was enhanced by co-doping with Li+ ions. The simplified Judd–Ofelt (J–O) theory has been performed to explain a detailed analysis of the luminescence spectra.

Cytotoxicity Evaluation of High-Temperature Annealed Nanohydroxyapatite in Contact with Fibroblast Cells

Biomaterials are substances manufactured for medical purposes in direct contact with the tissues of organisms. Prior to their use, they are tested to determine their usefulness and safety of application. Hydroxyapatites are used in medicine as a bony complement because of their similarity to the natural apatite therein. Thanks to their bioactivity, biocompatibility, stability and non-toxicity hydroxyapatite are the most commonly used materials in osteoimplantology. The use of materials at the nanoscale in medicine or biology may carry the risk of undesirable effects. The aim of the study was to evaluate the cytotoxic effect of high-temperature annealed nanohydroxyapatites on the L929 murine fibroblasts. Nanohydroxyapatites in powder form were obtained by the wet chemistry method: in the temperature range of 800–1000 °C and used for the study. Based on performed studies evaluating the morphology and fibroblast viability, it was found that nanohydroxyapatites show no cytotoxic effects on the L929 cell line.

Forgotten and Resurrected Chernovite-(Y): YAsO4 Doped with Eu3+ Ions as a Potential Nanosized Luminophore

In the present work, a precipitation method was employed to prepare nanosized YAsO4 doped with Eu3+ ions. The raw nanomaterials have been thermally treated in a temperature range between 500 and 900 °C for 3 h. The XRD analysis demonstrated that the powders were single-phase nanopowders with high crystallite dispersion. Our studies were focused on relating the luminescence properties of the Eu3+ dopant to the nanocrystallite (NC) size. The average NC size varied accordingly between 15 and 45 nm. We have found that the size effect is manifested mainly in the expansion of the cell volume and broadening of XRD peaks, as indicated by Rietveld analysis. Moreover, the emission and excitation spectra, although typical for Eu3+ ions, demonstrated some degree of variability with calcination temperatures and doping concentration. To explain these differences, a detailed analysis of luminescence spectra by the Judd-Ofelt theory has been performed.

Preparation of up-converting nano-biphasic calcium phosphate

The nano-biphasic calcium phosphate co-doped with 1 mol% Er3+ and 5 mol% Yb3+ ions was prepared using Pechinis technique. The preparation of the biphasic calcium phosphate showed the removal of fluorine ions from the matrix. The structural properties and morphology of the particles were studied by means of XRD (X-ray powder diffraction), TEM (Transmission Electron Microscopy), and SEM (Scanning Electron Microscopy) techniques. The spectroscopic properties of Ca10(PO4)6F2/Ca3(PO4)2:Er3+,Yb3+ nano-biphasic calcium phosphate were investigated in detail using emission spectra, power dependence and emission kinetics. This material demonstrated intense green up-conversion depending on laser power. Additionally, the luminescence lifetimes for Er3+ ions were calculated from the measured decays. Power dependence of the green and red emissions was found to result from a temperature increase of nano-biphasic calcium phosphate that opens potential applications in theranostics.

Influence of annealing temperature on the spectroscopic properties of hydroxyapatite analogues doped with Eu3

Calcium hydroxyapatite (CaHAp) and strontium hydroxyapatite (SrHAp) nanopowders doped with 2 mol% Eu3+ ions were obtained by using a microwave-assisted hydrothermal method and thermally treated in the temperature range from 450 to 950 °C for 3 h. XRD (X-ray powder diffraction) and TEM (transmission electron microscopy) techniques, as well as Raman and IR (infrared) spectroscopy, were used in order to determine the structural and morphological properties of the synthesized materials. The XRD patterns confirmed the crystal purity and nanometer size of the obtained materials. Nanoparticles were obtained as a function of the dopant concentration and annealing temperature in the size range from 50 nm for CaHAp samples to 80 nm for SrHAp samples. The luminescence properties of calcium and strontium hydroxyapatite doped with Eu3+ ions and their dependence on the annealing temperature were investigated in detail. Three distinct lines were observed for CaHAp samples and one line for SrHAp samples, which corresponded to 5D0 → 7F0 transitions. Moreover, a weak and broad emission corresponding to the 4f65d1 → 4f7 (8S7/2) transition of Eu2+ ions was observed in both cases. The Judd–Ofelt (J–O) theory was applied and a detailed analysis of the observed structural and spectroscopic measurements was performed and described.

Structure and Luminescence Properties of Nanofluorapatite Activated with Eu 3+ Ions Synthesized by Hydrothermal Method

Nanotechnology is the most intensively developing a multidisciplinary field of research combining various disciplines of science achievement. Nanomaterials show unexpected and interesting chemical and physical properties different from those of the original in the micro-sized scale. A success of nanotechnology in field of physical, chemical, and medical sciences, it has now started revolutionizing the regenerative medicine as well as theranostic.

Effects of crystalline growth on structural and luminescence properties of Ca(10−3x)Eu2x(PO4)6F2 nanoparticles fabricated by using a microwave driven hydrothermal process

Eu3+ doped fluorapatite nanopowders were synthesized by a microwave assisted hydrothermal technique and annealed in the 500–1000 °C temperature range for 3 h. The europium ion concentration was determined to be in the 0.5–10 mol% concentration range. The morphology and structural properties of Ca(10−3x)Eu2x(PO4)6F2 were determined by using TEM (transmission electron microscopy) and XRPD (X-ray powder diffraction) techniques, as well as the IR (infrared) and Raman spectroscopy. The average nanoparticle sizes were calculated by Rietveld refinement to be in the range from 30 nm for the as-prepared samples to above 100 nm for the materials thermally treated at 1000 °C. The particles developed into rectangular prism nanorods. The spectroscopic properties of the obtained materials were observed to be dependent on the dopant concentration and annealing temperature and were studied in detail. The Judd–Ofelt theory was applied and correlated with structural and optical properties to get detailed insight into the fluorapatite structures.