Biological Materials Science: Biomaterials II
Sponsored by: TMS Functional Materials Division, TMS Structural Materials Division, TMS: Biomaterials Committee
Program Organizers: Steven Naleway, University of Utah; Jing Du, Pennsylvania State University; Rajendra Kasinath, DePuy Synthes (Johnson and Johnson); David Restrepo, University of Texas at San Antonio
Wednesday 8:30 AM
February 26, 2020
Room: Leucadia
Location: Marriott Marquis Hotel
Session Chair: David Restrepo, University of Texas at San Antonio; Claire Acevedo, University of Utah
8:30 AM Cancelled
Reinforcement of Low Cost Additively Manufactured Prosthetic Sockets to Create Resilient Laminate Materials: Isaac Cabrera1; Joseph Martin1; Samantha Fong1; KiAsia Lawson2; Ramesh Rao1; Albert Lin1; Joanna McKittrick1; 1University of California San Diego; 2North Carolina A&T State University
One of the main problems of prosthetic sockets made with additively manufactured polymers is that the available materials often fail in brittle fracture. We can improve the fracture toughness of these prosthetic socket materials by creating composites where a thin polymer or fiber reinforced layer is added to the exterior of the socket without needing to adjust the additive manufacturing process conditions. We examined multiple combinations of additively manufactured polymers with different coating materials to determine which composite has the highest fracture toughness per unit cost. We take inspiration from natural laminate structures to improve the design of our laminated additively manufactured prosthetic sockets.
8:50 AM
Corrosion Behaviour of Modern Ti-based Biomedical Materials in the Simultaneous Presence of Albumin and Hydrogen Peroxide: Agata Sotniczuk1; Donata Kuczynska-Zemla1; Halina Garbacz1; 1Warsaw University of Technology
Typical corrosion tests of titanium for biomedical applications are usually performed in solutions such as physiological saline or PBS (phosphate-buffered saline). Nevertheless, implants in the human body are exposed to the range of other molecules including proteins (such as albumin) and ROS (reactive oxygen species, such as hydrogen peroxide). The latest investigations (related to commercially used Ti6Al4V) indicate that the influence of proteins and ROS should be investigated in combination taking into account the unfavourable synergistic effect of these two factors. In this study the effect of simultaneous presence of proteins and ROS on the corrosion resistance has been investigated for modern Ti-based materials with lack of potentially harmful alloying elements (such as bulk nanocrystalline alpha Ti or metastable beta Ti alloy). Corrosion resistance was analysed based on the results of electrochemical tests (EIS, potentiostatic polarization) combined with surface analysis (AFM, XPS). This work was supported by NCN Poland [2018/29/N/ST8/02306]
9:10 AM
Micro-scratch of Irradiated Compression Molded Ultra High Molecular Weight Polyethylene (UHMWPE) based Nanocomposites: Chinmayee Nayak1; Ariharan S2; Vamsi Krishna Bhalla3; Kantesh Balani1; 1Indian Institute of Technology, Kanpur; 2Indian Institute of Technology Madras; 3University of Louisville
In present work, UV and gamma irradiation at 15 kGy and 25 kGy doses, respectively, were performed on as-processed ultra-high molecular weight polyethylene (UHMWPE) reinforced with alumina, hydroxyapatite and carbon nanotubes. The novelty of this work is to study the micro-scratch resistance and cytocompatibility of irradiated UHMWPE nanocomposites. Hardness (H) and reduced elastic modulus (Er) of irradiated nanocomposites are increased by ~1.5 times compared to that of as-processed UHMWPE (H: ~0.07 GPa and Er: ~1.25 GPa) due to crosslinking which diminishes the plastic deformation under load. During progressive scratch, hardening of hydroxyapatite, lubrication of CNT and enhanced hardness of irradiated nanocomposites contributed to up to 20% high coefficient of friction and nearly ~1.5-3 times lower wear rate than that of as-processed nanocomposites. The results establish irradiation as a positive factor of influence on tribological properties of as-processed UHMWPE nanocomposites. The irradiated samples are cytocompatible to L929 mouse fibroblast cells.
9:30 AM
Processing, Microstructure Characterization and Biological Response of Cold Sprayed Biocomposite Coatings: Eden Bhatta1; Grant Crawford1; 1South Dakota School of Mines and Technology
Hydroxyapatite (HA) is commonly used in bioactive coatings to facilitate direct bonding of titanium (Ti) implants with living bone tissue. The coating encourages rapid osseointegration behavior which is suggested to prolong implant lifespan. Cold sprayed coatings of HA on Ti implants have the potential to overcome some of the disadvantages of plasma sprayed HA coatings. We report on the relationship between processing, microstructure characterization, and biological performance of biocomposite cold sprayed coatings. HA-Ti powders were pre-processed using high energy ball milling (HEBM) that allows formation of composite powders and improves deposition efficiency during cold spray deposition. Milled powders and as-processed coatings were characterized using scanning electron microscopy and x-ray diffraction. Adhesion strength of the coatings was measured using a tensile pull-off test. Biological performance of the as-deposited coatings was characterized via in vitro cell culture using mouse osteoblasts. Osteoblast viability, differentiation, and mineral deposition were investigated.
9:50 AM Invited
Decussation Patterns in Mammalian Teeth Across Bite Force Regimes: Dwayne Arola1; Juliana Fernández-Arteaga2; Cameron Renteria1; Carli Marsico1; E. Alex Ossa2; 1University of Washington; 2Universidad Eafit
The enamel of mammalian teeth must resist wear and fracture under the range of bite forces that encompass oral functions. Damage tolerance is key. A principal contribution to the fracture resistance of this tissue is enamel rod decussation, i.e. an interesting pattern of weaving that give rise to the Hunter Schreger’s bands evident in white-light microscopy of this tissue. Due to its importance to lifelong health, enamel rod decussation in human teeth has been studied in some detail. However, the bite forces of humans are rather low with respect to that of other mammals. Our group has been exploring the decussation patterns in teeth of mammals in search of correlations of the enamel microstructure and function. This talk will present new results on the decussation patterns in teeth of various mammals representing a large range of bite forces, the spatial distribution in mechanical behavior, and the fracture resistance of enamel.
10:20 AM Break
10:35 AM
In-situ AFM Identification of Mechanical Properties of Collagen Fibrils and Extrafibrillar Matrix in Bone: Wei Gao1; Xiaodu Wang1; Heber Barron1; 1University of Texas at San Antonio
Bone is a natural composite material with a hierarchical structure consisting of three major components: mineral, organic matrix, and water. Water is present in three different compartments in bone matrix: freely mobile water in pores; bound water at the surface of the collagen fibrils and between the collagen and mineral phase; and structural water as part of collagen and mineral molecules. Water in every compartment contributes to different mechanical properties of the bone. It is known that bound water is present in both mineralized collagen fibrils (MCF) and extrafibrillar matrix (EFM). However, it is not clear on how bound water would affect the in situ mechanical behavior at the ultrastructural compartments. In this talk, we will present the effect of bound water on the mechanical properties of individual MCF and EFM under both dry and wet conditions using a high-resolution atomic force microscopy (AFM).
10:55 AM
Rate and Stress-state Dependent Calibration of FlexiForce Sensors for Injury Biomechanics Research: Andrew Brown1; Alexandra Vest1; Karin Rafaels1; 1U.S. Army Research Laboratory
The majority of head injuries are caused by dynamic events over a wide range of strain rates, from falls (100-101s-1) to military relevant ballistic and blast events (102-104s-1). Experimental injury biomechanics utilizing cadaveric and anthropomorphic devices are critical for developing human skull fracture criteria for predicting load transfer to the brain, informing computer models, and aiding in protective equipment design. FlexiForce® (Tekscan, Inc.) sensors show promise for injury biomechanics research applications, but calibration at high strain rates (>103s-1), forces (>1000N), and varied stress-states requires investigation. Custom Op-Amp circuitry has been implemented to increase the FlexiForce® A301 sensor working range from 445 to ~40,000N. Sensors were quasi-statically loaded for baseline voltage-force calibration under uniaxial compression and under varied shear-stresses using angled platen pairs. High-rate experiments for uniaxial compression and varied shear-stresses were conducted using Split-Hopkinson Pressure Bar technique. Rate and stress-state dependent calibration curves have been developed for FlexiForce® sensors.
11:15 AM
Mechanisms of Co-ion Release from Titanium-cobalt Hip Implants Revealed by Atomic Scale Correlative Microscopy: Shanoob Balachandran Nair1; Zita Zachariah1; Alfons Fischer1; David Mayweg1; Markus Wimmer2; Dierk Raabe1; Michael Herbig1; 1Max-Planck-Institut fuer Eisenforschung; 2Rush University Medical Center
Millions of patients per year receive a hip implant as treatment for end-stage arthritis. These hip implants often consist of a cobalt alloy (Co-30Cr-5Mo) femoral head and a titanium alloy (Ti-6Al-4V) femoral stem. In-vivo fretting corrosion at the head-neck taper junction can lead to release of metal ions (specifically Co and Cr from the cobalt alloy) and metal wear particles, creating adverse local and systemic effects in the patient. Correlative transmission electron microscopy / atom probe tomography reveals the mechanism of nano-structural and atomic scale chemical alterations in the subsurface of titanium alloy subjected to in-vitro fretting under conditions similar to those occurring in-vivo in the hip. The fretting motion promotes tribocorrosion and hence Co-ion release from the more wear resistant cobalt alloy.