Drug loading capacity of microporous β-pyrophosphate crystals

Periodontitis and peri-implantitis are two characteristic examples where bacterial infections compromise the healing of dental tissues. Drug eluting scaffolds are a potential solution to this problem but their fabrication requires suitable biomaterials with significant drug loading capacity and regenerative potential to support new tissue formation. With this aim, porous β-pyrophosphate crystals having a micro-pore area of 2.59 m2/g and an average pore diameter of 65 nm, have been obtained by the heat treatment of brushite (at 780 °C). To demonstrate the drug loading potential of the mineral, experiments with chloramphenicol have been conducted. After tests with four common bacteria, the drug loaded mineral was shown to have enhanced antibacterial properties, particularly towards E. coli (74% growth inhibition) and S. aureus (48% growth inhibition). Taking into account β-pyrophosphate's significant role in hard tissue mineralisation and the capability to tailor crystal micro-porosity characteristics by controlled heat treatment, the mineral can be considered as an ideal biomaterial for localised drug delivery in dental applications

Antibacterial properties and regenerative potential of Sr²+ and Ce³+ doped fluorapatites; a potential solution for peri-implantitis

Scaffolds and implants in orthopaedics and regenerative dentistry usually fail because of bacterial infections. A promising solution would be the development of biomaterials with both significant regenerative potential and enhanced antibacterial activity. Working towards this direction, fluorapatite was synthesised and doped with Sr²+ and Ce³+ ions in order to tailor its properties. After experiments with four common bacteria (i.e. E. Coli, S. Aureus, B. Subtilis, B. Cereus), it was found that the undoped and the Ce³+ doped fluorapatites present better antibacterial response than the Sr²+ doped material. The synthesised minerals were incorporated into chitosan scaffolds and tested with Dental Pulp Stem Cells (DPSCs) to check their regenerative potential. As was expected, the scaffolds containing Sr²+-doped fluorapatite, presented high osteoconductivity leading to the differentiation of the DPSCs into osteoblasts. Similar results were obtained for the Ce³+-doped material, since both the concentration of osteocalcin and the RUNX2 gene expression were considerably higher than that for the un-doped mineral. Overall, it was shown that doping with Ce³+ retains the good antibacterial profile of fluorapatite and enhances its regenerative potential, which makes it a promising option for dealing with conditions where healing of hard tissues is compromised by bacterial contamination

Paclitaxel Magnetic Core⁻Shell Nanoparticles Based on Poly(lactic acid) Semitelechelic Novel Block Copolymers for Combined Hyperthermia and Chemotherapy Treatment of Cancer.

Magnetic hybrid inorganic/organic nanocarriers are promising alternatives for targeted cancer treatment. The present study evaluates the preparation of manganese ferrite magnetic nanoparticles (MnFe2O4 MNPs) encapsulated within Paclitaxel (PTX) loaded thioether-containing ω-hydroxyacid-co-poly(d,l-lactic acid) (TEHA-co-PDLLA) polymeric nanoparticles, for the combined hyperthermia and chemotherapy treatment of cancer. Initially, TEHA-co-PDLLA semitelechelic block copolymers were synthesized and characterized by 1H-NMR, FTIR, DSC, and XRD. FTIR analysis showed the formation of an ester bond between the two compounds, while DSC and XRD analysis showed that the prepared copolymers were amorphous. MnFe2O4 MNPs of relatively small crystallite size (12 nm) and moderate saturation magnetization (64 emu·g-1) were solvothermally synthesized in the sole presence of octadecylamine (ODA). PTX was amorphously dispersed within the polymeric matrix using emulsification/solvent evaporation method. Scanning electron microscopy along with energy-dispersive X-ray spectroscopy and transmission electron microscopy showed that the MnFe2O4 nanoparticles were effectively encapsulated within the drug-loaded polymeric nanoparticles. Dynamic light scattering measurements showed that the prepared nanoparticles had an average particle size of less than 160 nm with satisfactory yield and encapsulation efficiency. Diphasic PTX in vitro release over 18 days was observed while PTX dissolution rate was mainly controlled by the TEHA content. Finally, hyperthermia measurements and cytotoxicity studies were performed to evaluate the magnetic response, as well as the anticancer activity and the biocompatibility of the prepared nanocarriers

Design of a Multifunctional Nanoengineered PLLA Surface by Maximizing the Synergies between Biochemical and Surface Design Bactericidal Effects

This is an open access article published under an ACS AuthorChoice License. See Standard ACS AuthorChoice/Editors' Choice Usage Agreement - https://pubs.acs.org/page/policy/authorchoice_termsofuse.htmlNanotechnology, the manipulation of matter on atomic, molecular, and supramolecular scales, has become the most appealing strategy for biomedical applications and is of great interest as an approach to preventing microbial risks. In this study, we utilize the antimicrobial performance and the drug-loading ability of novel nanoparticles based on silicon oxide and strontium-substituted hydroxyapatite to develop nanocomposite antimicrobial films based on a poly(l-lactic acid) (PLLA) polymer. We also demonstrate that nanoimprint lithography (NIL), a process adaptable to industrial application, is a feasible fabrication technique to modify the surface of PLLA, to alter its physical properties, and to utilize it for antibacterial applications. Various nanocomposite PLLA films with nanosized (black silicon) and three-dimensional (hierarchical) hybrid domains were fabricated by thermal NIL, and their bactericidal activity against Escherichia coli and Staphylococcus aureus was assessed. Our findings demonstrate that besides hydrophobicity the nanoparticle antibiotic delivery and the surface roughness are essential factors that affect the biofilm formation

A numerical method to solve higher-order fractional differential equations

In this paper, we present a new numerical method to solve fractional differential equations. Given a fractional derivative of arbitrary real order, we present an approximation formula for the fractional operator that involves integer-order derivatives only. With this, we can rewrite FDEs in terms of a classical one and then apply any known technique. With some examples, we show the accuracy of the method

Novel poly(butylene succinate) nanocomposites containing strontium hydroxyapatite nanorods with enhanced osteoconductivity for tissue engineering applications

Three series of poly(butylene succinate) (PBSu) nanocomposites containing 0.5, 1 and 2.5 wt% strontium hydroxyapatite [Sr5(PO4)3OH] nanorods (SrHAp nrds) were prepared by in situ polymerisation. The structural effects of Sr5(PO4)3OH nanorods, for the different concentrations, inside the polymeric matrix (PBSu), were studied through high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). HAADF-STEM measurements revealed that the SrHAp nanorods at low concentrations are dispersed inside the polymeric PBSu matrix while in 1 wt% some aggregates are formed. These aggregations affect the mechanical properties giving an enhancement for the concentration of 0.5 wt% SrHAp nrds in tensile strength, while a reduction is recorded for higher loadings of the nanofiller. Studies on enzymatic hydrolysis revealed that all nanocomposites present higher hydrolysis rates than neat PBSu, indicating that nanorods accelerate the hydrolysis degradation process. In vitro bioactivity tests prove that SrHAp nrds promote the formation of hydroxyapatite on the PBSu surface. All nanocomposites were tested also in relevant cell culture using osteoblast-like cells (MG-63) to demonstrate their biocompatibility showing SrHAp nanorods support cell attachment

Novel poly(butylene succinate) nanocomposites containing strontium hydroxyapatite nanorods with enhanced osteoconductivity for tissue engineering applications

Three series of poly(butylene succinate) (PBSu) nanocomposites containing 0.5, 1 and 2.5 wt% strontium hydroxyapatite [Sr5(PO4)3OH] nanorods (SrHAp nrds) were prepared by in situ polymerisation. The structural effects of Sr5(PO4)3OH nanorods, for the different concentrations, inside the polymeric matrix (PBSu), were studied through high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). HAADF-STEM measurements revealed that the SrHAp nanorods at low concentrations are dispersed inside the polymeric PBSu matrix while in 1 wt% some aggregates are formed. These aggregations affect the mechanical properties giving an enhancement for the concentration of 0.5 wt% SrHAp nrds in tensile strength, while a reduction is recorded for higher loadings of the nanofiller. Studies on enzymatic hydrolysis revealed that all nanocomposites present higher hydrolysis rates than neat PBSu, indicating that nanorods accelerate the hydrolysis degradation process. In vitro bioactivity tests prove that SrHAp nrds promote the formation of hydroxyapatite on the PBSu surface. All nanocomposites were tested also in relevant cell culture using osteoblast-like cells (MG-63) to demonstrate their biocompatibility showing SrHAp nanorods support cell attachment