Materials Science Forum Vol. 805

Abstract: Titanium alloys and stainless steel have been widely used in the production of prostheses, medical and dental devices, due to resistance and anticorrosive properties. Despite that, the values of the elastic modulus of these alloys are about 3-5 times higher than the human bone. So, many researches have sought alternatives to these alloys, in order to obtain alloys with good mechanical strength, low modulus of elasticity and excellent biofunctionality. This work highlights by scientific and technological form, the collection and analysis of the module of elasticity and chemical composition, related to normalizations. The properties obtained, being inadequate, highlights the danger of bone absorption, causing loss of adhesion of the prosthesis and reducing its useful life, In addition, chemical abnormalities are a fundamental problem in terms of risk. Results of this study are shown and analyzed.

Abstract: Titanium and titanium alloys are currently being used for clinical biomedical applications due to their high strength, corrosion resistance and elastic modulus. However, these materials have recently been shown to exhibit ion release and poor physiological integration that may result in fibrous encapsulation and further biomaterial rejection. In order to be a successful replacement for bone current approaches for enhancing the mechanical and biological properties of Ti was alloyed Ti with Ta due to it provides greatly improved mechanical properties which include fracture toughness and workability. Studies have shown techniques such ion beam etching, heat and alkaline treatment, SBF coatings and anodization to promote altered cellular response on Ti and Ti-alloys. In this study Ti-30Ta alloy was investigated ion beam etching. The SEM was used to investigate the topography, EDS the chemical composition, and surface energy was evaluate with contact angle analyze due to the topography have effect on protein adsorption, platelet adhesion, blood coagulation and bacterial adhesion. This study concludes Ti-30Ta alloy substrate with ion beam etching was not favorable for biomedical application.

Abstract: Recent studies have identified strong correlations between anodized metals and the production of highly biomimetic nanoscale topographies. These surfaces provide an interface of enhanced biocompatibility that exhibits a high degree of oxidation and surface energy. In this study, Human dermal fibroblasts (HDF, neonatal) were utilized to evaluate the biocompatibility of Ti-30Ta nanotubes after 1 day of culture. The anodization process was performed in an electrolyte solution containing HF (48%) and H₂SO₄ (98%) in the volumetric ratios 1:9 with the addition of 5% dimethyl sulfoxide (DMSO) at 35V for 40 min. Cellular analysis identified improved fibroblast functionality on the nanotube surface, showing increased elongation, and extracellular matrix production on the Ti-30Ta nanotubes. The results presented identify improved cellular interaction on Ti-30Ta nanotubes as compared to the control substrates. Thus, the formation of the nanotube on Ti30Ta alloy may have potential application as interface for implantable devices.

Abstract: This work reports the development and characterization by SEM, XRD, FTIR, emission and excitation chisonan/ZnAl_1.9Eu_0.05O₄ films with a mass proportion of 1:1. The powders were deagglomerated and passed 325 mesh screens and added to the diluted chitosan in 1% acetic acid. The materials were filtered and placed in petri dishes and placed in an oven at 60°C for solvent evaporation. After drying the film, a solution of 1M sodium hydroxide was added in order to obtain a film with neutral pH. With the XRD, it has been verified that the chitosan/ZnAl_1.9Eu_0.05O₄ films presented the chitosan peaks and ZnAl₂O₄. Through the SEM, it has been observed that the chitosan/ZnAl_1.9Eu_0.05O₄ presented a protruding surface. The results presented in emission and excitation spectra suggest that the film chitosan/ ZnAl_1.9Eu_0.05O₄ exhibit good luminescence properties, and are promising to be applied as a luminescent marker in future applications in the field of biomaterials.

Abstract: Chitosan films have been used as dressings for healing burns. The physical and biological properties of these films can be modified by the addition of bioactive substances such as phytotherapics. This work used the casting - solvent evaporation technique for the preparation of chitosan film containing hydrophilic or hydrophobic phytotherapic. The barrier properties, mechanicals properties and microbial penetration were evaluated. The results showed that the films containing the hydrophobic herbal showed lower ability to move fluid and permeability to water vapor compared to the film containing the hydrophilic herbal. For the determination of microbial permeation, film were previously sterilized and were fixed in the mouth of glass vials containing sterile nutrient broth and left on the lab bench for a period of 10 days. Negative and positive controls were also conducted. The chitosan films do not allow the microbial penetration.

Abstract: The present study reports on a novel approach for the development of enzymatic biosensor systems using chemically functionalized supports. Silica glass slides were surface-modified by reacting with organosilanes at room temperature and a glucose oxidase (GOx) enzyme layer was covalently immobilized using the bi-functional linker glutaraldehyde (GA). The activities of enzymes in solution and immobilized on hydroxyl-, amine-and thiol-modified glass surfaces were tested by sensing β-D-glucose with the horseradish peroxidase (HRP) mediated oxidation of 3,3’,5,5’-tetramethylbenzidime hydrochloride (TMB) by H₂O₂ based on biochemical reactions. The results indicated that the intensity and overall kinetics of the enzymatic catalysis were dependent on solid support chemical functionality with the amine-modified support providing the highest enzymatic catalytic activity.

Abstract: Quantum dots (QDs) are very promising advanced materials due to their nanoscale dimensions and properties of quantum confinement. Among the most promising applications of QDs, the use as biomaterials is highlighted, especially as optical biosensors and biomarkers. In this work CdSe-CdS core-shell nanoparticles were obtained through colloidal aqueous route at room temperature. The biocompatible polymer poly (vinyl alcohol) modified with carboxyl groups (PVA-COOH) was used as a stabilizing agent. The effect of growing CdS shell on the quantum properties and dimensions of CdSe nanoparticles (core-shell structure) was studied by UV-vis spectroscopy, photoluminescence (PL) and transmission electron microscopy (TEM). The results showed the influence of the growth of the CdS shell layers in the optical properties of quantum dots. Based on the results it can be stated that conjugated systems of CdS/CdSe-PVA-COOH were obtained and exhibited enhanced photoluminescent behavior, an essential property to use this system in biosensing devices.

Abstract: Plasma polymerized diglyme (pp-diglyme) is a promising class of biomedical materials due to hydrophilic features when deposited under excitation by RF low power. In order to reach this goal this paper deals with plasma polymerization of diethylene-glycoldimethyl-ether (diglyme here after) by RF-excited plasmas under power ranging from 5 to 20 W and pressure of 6.6 Pa. Films were deposited on glass and aqueous polyurethane dispersion substrates (PUD). For the values of RF used in this paper, film thickness varied from 51 nm to 64 nm. Such films were deposited on flexible biocompatible polyurethane that is not resistant to acids and bases as plasma polymerized diglyme. The recovering of these materials with pp-diglyme films let them with a resistant biocompatible feature that is appropriate for use in aggressive environments. The contact angle measurements show the variation from 56° to 64° for a surface energy which varies from 68 mJ/m² to 59 mJ/m², respectively. The FTIR data show that the main functional groups in the polymeric film structure are C-H (3000 cm^-1 to 2900 cm^-1), C-O-C and C-O (1200 cm^-1 to 900 cm^-1) similar to the polyethylene oxide (PEO) structure. The refractive index results show a variation from 1.58 to 1.63.

Abstract: In this paper we propose nanoferrites Ni-Zn silanization with 3-aminopropyltrimethoxysilane using the method of reflux and evaluate the effect of silanization on the structure, morphology and magnetism of the magnetic nanoparticles aimed at biological applications. The samples as synthesized and after silanization were characterized by XRD, FTIR, SEM and testing magnetic attraction. The results indicated a single phase inverse spinel Ni-Zn ferrite, high intensity of diffraction peaks and a high basal width of all reflections observed, indicating that the samples are crystalline, and formation of nanoparticles. Morphologically, for nanoferrites Ni-Zn synthesized observed formation of large agglomerates in the form of spongy blocks of frail and after silanization was observed with respect dense pellets, indicating that most particles were rigidly connected by the presence of the agent silane. The characteristic bands of the spinel were observed for the Ni-Zn nanoferrites before and after silanization, and also observed the characteristic bands of silane in confirming the ferrites silanized functionalization of ferrites with the silane agent. Nanoparticles ferrite as synthesized and after silanized were strongly attracted by the presence of a magnet, immediately after the presence thereof indicating that the silane is effective is not interfere with the magnetic particles, maintaining the same magnetic behavior.

Abstract: This paper aims to synthesize by combustion reaction and silanilized of the ZnAl_1.9Eu_0.1O₄, with silane agent 3-aminopropyltrimethoxysilane. The characterization of materials before and after silanization was investigated. Nanoparticles ZnAl_1.9Eu_0.1O₄ was obtained according to the theory of propellants and explosives using the synthesis combustion reaction. The samples were deagglomerated and passed through a sieve of 325 mesh and added to 3-aminopropyltrimethoxysilane, followed by heat shock treatment by ultrasonic and microwave. Subsequently centrifuged and dried at 150 ° C for 24 hours. The samples before and after the silane were characterized by X-ray diffraction, infrared spectroscopy and thermogravimetric analysis. The results indicate the formation of a major phase spinel normal ZnAl₂O₄, and the EuAlO₃ peaks as secondary phase. The FTIR spectra for ZnAl_1.9Eu_0.1O₄ have absorption bands below 1000 cm^-1, and after silanization showed bands of C = O, axial strain - CN and Si-O bands, which proves the silanization. The thermogravimetric curves showed good thermal stability, with mass loss around 30%.