Advances in Science and Technology Vol. 86

Abstract: α-TCP/HAp functionally graded porous beads were prepared for use as a scaffold for bone regeneration. In this research, porous beads which have compositionally graded layer, from TCP of inner area to HAp of surface area, were fabricated. It is known that the dissolution rate of TCP is fast in compare with that of HAp in living body, thus the inner area would dissolve prior to the surface area. These beads to allow the penetration of cells and blood vessel into the inner area of beads following new bone regeneration. At present, conditions to fabricate the functionally graded porous beads have been established already, and experiments using cells [MC3T3-E1] are in progress.

Abstract: Recently, regenerative medicine attracts very wide attention. Regenerative medicine is a method of medical care for the purpose of recovery of the lost human organic function, resulted by an accident or diseases. It is considered that there are three important factors in the regenerative medicine, cell, scaffold and cell growth factor. In this research, the talyor made stereolithography method was used to fabricate a highly precise biodegradable scaffold which is suited for individual bone defect part. The sterolithograph, one of rapid prototyping methods, is a method of modeling by using optical hardening resin irradiated by ultraviolet laser. We have used the optical hardening resin by mixing biodegradable β-tcp as the bone formation material. At present, confirmation of detailed fabrication conditions of stereolithography are in proceeding. Experiments by using osteoblasts cells are intended.

Abstract: In this work, we report on the development of a multifunctional and photo-inducible nanoplex made of chitosan (Ch) and hyaluronic acid (HA) for delivery of nucleic acid. Self-assembled Ch/HA nanoparticles were attached to ortho-nitrobenzyl (o-NB) photo-labile molecules (PL)-gold nanoparticles via thiol groups and to QDs-conjugate ssDNA through amide bond linkage to form nanoplexes (Ch:HA:AuPL:QD-DNA). The composition of DNA nanocarriers was validated by nuclear magnetic resonance, transmission electronic microscopy, energy dispersive x-ray spectroscopy, gel electrophoresis and spectrophotometry. The change in zeta potential (34 ± 11 to -26 ± 11 mV) and the loss of the o-NB characteristic peaks in nuclear magnetic resonance spectra, after the exposure of the PL molecule to ultraviolet light, both confirmed the photo-labile properties of the system. The potential of the nanoplexes to induce high cell transfection was assessed by flow cytometry and fluorescent microscopy imaging. Over 30% transfection of HEK-293 was obtained with the nanoplexes after a one-minute exposure of cells to UV light. This corresponds to a 15% increase in the transfection efficiency compared to unexposed Ch:HA:AuPL:QD-DNA nanocarriers. This high transfection efficiency was associated with the unique design of the carrier system and its photo-responsiveness feature for facilitating the DNA release.

Abstract: We report on the synthesis and characterization of porous monodisperse vaterite containers with controllable average sizes from 400 nm to 10 μm. Possible release strategies of enclosed substances via recrystallization or by pH-change are presented. As a model experiment, a fluorescent marker was encapsulated and imaged by two-photon microscopy to monitor the dye release. The release process was found to be controllable via the immersion medium’s properties. Release times can be further tuned by covering the containers with additional polymer layers, creating a flexible system with promising perspectives for pharmaceutical applications.

Abstract: Since the promising virus -based gene therapies are often limited by problems such as the immunity of virus itself, the development of an efficient non-viral vector is of prime importance. For this reason, several synthetic nonviral polymeric carriers including cationic sequences have been molecularly designed. It is well known that the polymeric carriers with some cationic groups buffer the endosomal pH resulting in the enhanced transfection efficiency, but also in a relatively high toxicity. In the last decades, the polymers bearing pendant carbohydrates (glycopolymers) was proved to have relatively less toxic. Since the glycopolymers may not only decrease the toxicity of the cationic chain but also serve as targeting agent, we have rationally designed new glycopolymer-based gene delivery carriers. The interaction of carrier/gene polyplexes with hepatocytes and their intracellular trafficking were investigated in vitro. Our results show the significant efficacy of the galactose moieties on the uptake by hepatocytes, in a ligand specific manner.

Abstract: Abstract. Hydrogels based on poly (N-vinyl-2-pyrrolidone) (PVP) obtained by ionizing radiation are sterile, biocompatible can be used as topics dressings. Due to the high degree of hydration of the gel, it has a low mechanical strength, which is one of the biggest problems in its application. The objective of this work was to study the properties of the hydrogel based on PVP / sodium alginate containing pseudoboehmites nanoparticles treated with octadecylamine for pharmaco applications, order drug release when immobilized on a matrix of PVP/sodium alginate/pseudoboehmite. Pseudoboehmite nanoparticles were obtained by sol-gel route, from aluminum nitrate and ammonia as precursors, and subsequently were treated with octadecylamine. The hydrogels based on PVP/sodium alginate/pseudoboehmite treated were prepared by ionizing radiation with doses of 30 and 35kGy. The characterization of hydrogels obtained was made by means of thermomechanical (tensile tests, DTA and TG) and physicochemical (swelling, sol-gel fraction) tests. The results obtained showed that the hydrogel based only on PVP and sodium alginate showed highest tensile strength. The presence of pseudoboehmite in the hydrogels decreases the formation of crosslinks, while the presence of PEG in the agar and causes a decrease in Tg of the polymer matrix.

Abstract: Abstract: The structure of aluminum monohydroxide resulting from synthesis by ammonium hydroxide with aluminum chloride (or aluminum nitrate, for example) by a sol-gel process, gives a purified and chemically inert material with many applications possibilities because of its great specific surface area. A pseudoboehmite is the choice in this project for adsorption/desorption of atenolol. The molecular interaction with the pseudoboehmite substrate was studied by FTIR (Infrared Spectroscopy), DSC (Scanning electron /TG Thermogravimetry), UV-vis (Ultraviolet-visible spectroscopy) and SEM (Scanning Electron Microscopy). The SEM characterization has been used to quantify the local structural surface for the correlations with the synthesis process; and the Spectroscopies and Thermogravimetric techniques were used for measurements of the adsorption/desorption concentrations of the drug in physiological solution. This procedure gives information to the chemistry and surface of these fine ceramics material that would be applied like excipient in medications to control the drug delivery and plasmatic concentrations in optimal conditions.