Next Generation Biomaterials: Next Generation Biomaterials IV
Sponsored by: ACerS Bioceramics Division
Program Organizers: Roger Narayan, University of North Carolina; Sanjiv Lalwani, Lynntech, Inc.
Wednesday 8:00 AM
October 12, 2022
Room: 318
Location: David L. Lawrence Convention Center
Session Chair: Russell Lee Leonard, University of Tennessee Space Institute; Annaliza Perez-Torres, University of Kentucky
8:00 AM Invited
Using Glass Ceramics to Improve the Detective Quantum Efficiency of Indirect Flat Panel Detector Systems: Russell Leonard1; Emily Moore1; Austin Thomas1; Lino Costa1; Brian Canfield1; Adrian Howansky2; Anthony Lubinsky3; Jacqueline Johnson1; 1University of Tennessee Space Institute; 2Stony Brook University Hospital; 3SUNY Stony Brook
Modern indirect flat panel detectors (I-FPDs) have many practical uses in medical imaging. The detective quantum efficiency (DQE) of these detectors could be improved, however, through increased detection of incident x-rays. The effectiveness of replacing the substrate in an I-FPD with a scintillating glass ceramic is explored. Several series of glass and glass-ceramic scintillators based on a borate glass composition were synthesized. Pertinent characteristics of the scintillators were determined including glass transition and crystallization temperatures and x-ray emission spectra. The light output of the samples in comparison to a commercial scintillator, gadolinium oxysulfide (GOS), was determined. Controlled crystallization in the glass-ceramic materials led to a greater than 100% increase in light output. The results indicate that incorporating scintillating glass-ceramic substrates into the I-FPD design will improve the DQE of the system. Several avenues exist for further improvements in performance.
8:20 AM
Microstructural and Mechanical Characterization of Three-dimensional Porous Titanium Carbide Structures Fabricated by Powder Technology: Joaquin Villalba-Guevara1; Ena Athenea Aguilar-Reyes1; Carlos Alberto León-Patiño1; 1Universidad Michoacana de San Nicolás de Hidalgo
Titanium implants have osseointegration limitations in orthopedic applications, so a coating process is necessary to improve their biological response. Titanium carbide (TiC) has been investigated as a biomaterial in the form of a thin film used in metallic scaffolds as a site for adhesion and cell proliferation, also for improving the osseointegration. However, it is possible the fabrication of three-dimensional porous TiC structures with mechanical properties suitable for applications in bone restoration. This investigation is focused on the fabrication of TiC foams by powder technology from mixtures of commercial titanium hydride powders, phenolic resin, and a foaming agent as precursors materials in various proportions. Microstructure, composition, and phases of TiC foams were characterized by scanning electron microscope (SEM) and X-ray diffraction. An overall porosity of the sintered samples ranges from 81 to 91 % with a pore size of 15-800 μm. The compressive strength and elastic modulus are also reported.
8:40 AM
Structural Analysis of Silver and Copper Substituted Hydroxyapatite for Biomedical Applications: Sierra Kucko1; Timothy Keenan1; 1Alfred University
Hydroxyapatite (HA) is widely employed for the repair or replacement of damaged hard tissue due to its compositional and structural similarities to natural HA. HA’s hexagonal crystal structure allows for modification with various ion substitution(s). Thus, metal ions such as Ag+ and Cu2+ have gained attention due to their antibacterial capabilities with their successful incorporation being proven by several studies. Limited research has been conducted on the quantity of ions incorporated and how their quantity influences the crystal structure and subsequent properties. A series of Ag-HA and Cu-HA powders with varying ion substitution (mol%) are synthesized and evaluated by X-ray characterization to observe the effects of ion content on the lattice parameters and site occupancies. Ion leaching in aqueous solution is evaluated using inductively coupled plasma optical emission spectroscopy (ICP-OES) and the agar diffusion method is used to establish antibacterial efficacy.
9:00 AM
Microscopic Characterizations of Cross-linked Gelatin Electrospun Nanofibrous Scaffolds: Fang Zhou1; Tobias Hedkte2; Christian E H Schmelzer2; Juliana Martins de Souza e Silva3; 1Carl Zeiss Microscopy; 2Fraunhofer Institute for Microstructure of Materials and Systems; 3Institute of Physics, Martin Luther University Halle-Wittenberg
Damaged tissue regeneration via nanofibrous scaffolds requires designing an extracellular matrix (ECM)-like scaffold with a high surface area to volume ratio and high porosity for promoting homogeneous cell attachment and proliferation throughout the scaffold. Gelatin is a biodegradable and biocompatible natural biomaterial, which can be used to prepare nanofibrous scaffolds via electrospinning. After chemical cross-linking, the final gelatin scaffolds show random nonwoven architecture with interconnected pores that mimic the ECM of native tissues, providing a good environment for cell attachment and spreading. Imaging biomaterials composed of low-Z elements, which are nonconductive and beam sensitive, can be challenging. We show that low beam energy down to 100 eV in SEM and Zernike phase-contrast in XRM are adequate strategies to characterize the morphology of cross-linked gelatin nanofibrous scaffolds with high resolution. Results obtained allow further optimization and performance improvement of the gelatin nanofibrous scaffold.
9:20 AM
Understanding Proton Diffusion in Biocompatible Polymer Membranes: Gloria Bazargan1; Daniel Gunlycke2; 1NRC Research Associate, US Naval Research Laboratory; 2Chemistry Division, US Naval Research Laboratory
We explore proton diffusion in hydrated, maleic-acid-functionalized chitosan membranes using ab initio molecular dynamics (AIMD) simulations. Our simulations show that more frequent proton hopping between water molecules leads to an increase in the proton diffusion coefficient at higher water content in membranes based on 50 and 100% de-acetylated maleic chitosan. Moreover, mobile protons interact with the oxygen atoms of the 50% de-acetylated polymer’s acetyl groups, making them susceptible to protonation. The maleic acid group’s three oxygen atoms hydrogen-bond to water molecules in the membrane channels and are protonated less frequently than the acetyl groups.