Pan American Materials Congress: Advanced Biomaterials: Poster Session
Sponsored by: Third Pan American Materials Congress Organizing Committee
Program Organizers: Carlos Elias, Instituto Militar de Engenharia; Wen Yang, University of California, San Diego

Tuesday 5:30 PM
February 28, 2017
Room: Poster Area
Location: Marriott Marquis Hotel

Session Chair: Carlos Elias, Instituto militar de Engenharia

PAN-1: Control of Shell Thickness on CeO2-ZnO Core-shell by Surfactant Assisted Co-precipitation Methods: Felipe Sanhueza1; Ramalinga Mangalaraja1; Stephano Morales1; Saeed Farhang1; Elizabeth Elgueta1; 1University of Concepcion
    Cerium oxide (CeO2) nanoparticle is major compound in rare earth family and has received significant attention to block ultraviolet radiation. The zinc oxide (ZnO) is known for its good absorption properties at visible range. The present work aimed to synthesis CeO2-ZnO core-shell (CS) nanostructures by surfactant assisted coprecipitation method with the objective to improve the absorption range through the control ZnO shell thickness. The crystalline nature, particle size and shell thickness of CS were studied using X-ray diffraction, dynamic light scattering and transmission electron microscopy, respectively. Finally, to explore the optical properties we used UV-visible and photoluminescence spectroscopies. The structural analysis confirmed well crystalline in nature without any impurities and the nanostructures exhibited both fluorite and wurtzite phases which confirmed the formation of CeO2-ZnO CS. The optical absorption spectra showed a strong band at 300 nm and the photoluminescence measurement was carried out at an excitation wavelength of 310 nm.

PAN-2: Elastic Modulus of Ternary Titanium Alloys for Biomedical Applications: Marcos da Silva1; Raul Araújo1; Pedro Kuroda1; Carlos Grandini1; 1Unesp/Bauru
    Ti-20Zr-xMo and Ti-10Zr-yMo alloys system are promissing alloys for biomaedical applications, because they have no cytotoxic elements. The alloys were melted using an arc-melting furnace with a non-consumable tungsten electrode and water-cooled copper crucible, in argon-controlled atmosphere and, hot-rolled in order to obtain the samples for elastic modulus test. The materials characterization was made by x-ray diffraction , optical microscopy and scanning electron microscopy measurements. The measurements of elastic modulus were performed using dynamic mechanical analyzer and free decay vibrations . The results of XRD and SEM micrographs showed that in the prepared alloys have coexistence of alpha’, alpha’’ and beta phases, showing the beta stabilizing character of the added elements in alloys and for the elastic modulus, it can be observed that the addition of the solute in the two systems decreases the Young modulus. (Financial support: CNPq and FAPESP).

PAN-5: Injectable Bone Substitute of Fibroin and Nanohydroxyapatite: Maritza Buitrago1; Claudia Ossa1; 1Universidad de Antioquia
    Hydroxyapatite (HA) is the most similar calcium phosphate to mineral component of bones and hard tissues of the body, and the fibroin (SF) is a recent natural biomaterial obtained of the silk of the insects like the silkworms. In this work, HA nanorods were synthesized using precipitation reaction and hydrothermal treatment. HA powder obtained was characterized with DRX and TEM; SF was extracted of the cocoons of Bombyx Mori silkworm using separation and dilution methods. The obtained solution was characterized with FTIR and protein quantification. The injectable bone substitutes were fabricated with different relations of the components HA, SF and glutaraldehyde as crosslinker. The properties evaluated were: injectability using universal testing machine, and degradation in SBF during 21 days. The results show that the bone substitutes can be injectable manually. Also, degradation results were positive because the material did not modify the medium considerably.

PAN-6: Metal-vitreous Biocide Coating: Felipe Santos1; Sonia Mello-Castanho1; Antonio da Silva1; José Bartolomé2; Maria Teresa Prieto2; Elisa Fernandez-Garcia3; Claudinei Santos4; 1IPEN - USP; 2CSIC - UAM; 3CINN - University of Oviedo; 4UERJ/FAT
    Develop materials capable of to improve the osseointegration mechanisms is an important contribution in health care, especially in orthopedics and dentistry. Even when the materials provide good osseointegration characteristics (biocompatible) many implants may suffer infections in surgery. This project proposes to develop a vitreous material covering metallic surface of a biomaterial (titanium alloys and stainless steel) with biocide characteristic. This work provides preliminary results from these vitreous material based on glass system SiO2-CaO-Na2O-Me. This study realized the replace of the boron by niobium (Me=Nb), intending obtain good behavior in osseointegration (to comparative basis: composition with a considerable amount of boron had very good response as a biocide agent). Nb seems to be very useful on vitreous lattice. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and biocide activity.

PAN-7: Nature's Technical Ceramic: The Avian Eggshell: Eric Hahn1; Andrei Pissarenko1; Vincent Sherman1; Daniel Fernandes2; Marc Meyers1; 1University of California, San Diego; 2Biomaterials Laboratory, Military Institute of Engineering, Rio de Janeiro, Brazil
    Avian eggshells break easily when impacted at a localized point, however they exhibit an impressive resistance when subject to a well-distributed slow compressive load. The present research provides insight into the underlying mechanics by evaluating both macroscopic and microstructural features. Eggs of varying species and size, from quail to ostrich, and source, from regular to organic, are investigated. Careful loading configurations allowed compression experiments to be conducted along the long axis of the egg by using rounded rubber cushions between steel platens and the egg. The force at failure scales with egg size and shell thickness, reaching loads upwards of 5000N for ostrich eggs. Failure occurs by axial splitting parallel to the loading direction due to radial hoop tensile stresses developing on the outer shell. Finite element analyses are employed to correlate an applied force to lateral hoop stresses to assess the eggshell's strain and moduli.

PAN-8: Preparation and Characterization of Biodegradable Polymer Blend Reinforced with Bio-hydroxyapatite Nanoparticle: Pedro Reis1; Esperidiana Moura1; Felipe Lourenço2; Maria José Oliveira1; 1Instituto de Pesquisas Energéticas e Nucleares; 2Faculdade de Ciências Farmacêuticas
    Nowadays significant advances have been made in the development of biodegradable polymeric materials for biomedical applications. The purpose of this study was to preparation and characterization of biodegradable polymer blend reinforced with bio-hydroxyapatite nanoparticle from the eggshell by sonochemical method. Biodegradable polymer blends based on PLA and the PBAT reinforced with 1-5 wt. % of bio-hydroxyapatite were prepared by melt extrusion, using a twin screw extruder and injection molding machine to obtain specimen test samples. The specimen samples were submitted to gamma radiation sterilization at radiation dose up to 25 kGy. The effects of the bio-hydroxyapatite addition on properties of PLA/PBAT biodegradable blend wereinvestigated by tensile tests, XRD, DSC, SEM and TEM analysisand the correlation between properties was discussed. In addition,the microbiologic tests in order to evaluate the efficiency of radiation treatment on reduction of the original level of contamination.

PAN-9: Selective Laser Sintering of Co-Cr-Mo Alloy for Dental Applications: Claudinei Santos1; Alexandre Habibe1; Paula Silva2; Bruno Simba1; 1UERJ; 2USP-EEL
    In this work, the dental prosthesis based on Co-Cr-Mo alloy were developed using selective laser sintering technique (SLS). 61.1wt.%Co-25.6Cr-6.2Mo-5.5W atomized powder was characterized by X-Ray diffraction and scanning electron microscopy. Models of fixed-bridge were are designed in Solid Works software and laser sintered(EOSINT®M-270) at 1340°C, submitted to thermal stress relieving (750°C-45min under argon flow) and characterized by crystalline phases, relative density, microstructure, hardness, elastic modulus and coefficient of thermal expansion (CTE). The sintered samples present FCC-Co and HP-Co as crystalline phases, resulting from the cooling conditions which the layers were subjected during the application of heat induced by the laser beam. Relative density of 95.4%, CTE of 14,1x10-6/°C, hardness of 338HV and Young modulus of 208GPa were obtained in sintered samples. The results indicate properties in accordance with ASTM F1537, compatible with dental applications typically recommended for bridges containing 4 or more units or fully dense pontics.

PAN-10: Surface Characterisation of Anodised Zirconium with Proved Bioactivity: Andrea Gomez Sanchez1; Maria Katunar1; Silvia Cere1; 1INTEMA - CONICET
    Zirconium is covered with a thin film of native oxide that may thicken by anodisation in acidic media. Along with the thickening, the surface chemistry, the topography and electronic properties of the surface are modified. Cell attachment and proliferation assays evidenced an increase in bioactivity of anodised zirconium and low citotoxicity when compared with as received surfaces. These differences may be explained by the anodic oxide film presence. When comparing anodised samples obtained in different conditions, differences in bioactivity in vitro was evidenced, even though not major differences in the surface condition was found in a first stage of analysis including crystalline phases, chemical species present or film thickness. Therefore, in this work, an extensively comparative study of the surface characteristics of the as received, and anodised at 30 V and 60 V conditions is performed, with the aim of evaluating origin of the in vitro behavior.

PAN-11: Wear of TiO2 Nanofilm Synthetized on Ti6Al4V and 316 Stainless Steel: Jonathan M. Schuster1; Mario Rosenberger1; Carlos Schvezov1; 1IMAM (UNaM-Conicet)
    TiO2 nanofilm is known that good hemocompatibility for that reason is indicated to build cardiovascular devices. When the device involves movable pieces, an important requirement is to be wear resistant. In this work, the wear resistance of TiO2 nanofilm synthetized by the sol-gel dip-coating technique coating Ti6Al4V and 316 Stainless steel was determined. The wear test was performed in a reciprocating wear machine at loads ranged between 10 and 100 mN at a frequency of 30 Hz using a diamond tip as counterface. The influence of the roughness, type of substrate and heat treatment temperature was analyzed. It was founded that the roughness is the main factor that control the adhesion of the nanofilm. Besides, the wear resistance increases with the heat treatment temperature.