Society for Biomaterials: Biomaterial Applications: Dental and Orthopaedic Biomaterials
Program Organizers: Jessica Jennings, University of Memphis; Guillermo Ameer, Northwestern University; Danielle Benoit, University of Rochester; Jordon Gilmore, Clemson University
Wednesday 8:00 AM
October 12, 2022
Room: 316
Location: David L. Lawrence Convention Center
Session Chair: Jordon Gilmore, Clemson University
8:00 AM Invited
Silver Doped Titanium Oxide Layers for Improved Photocatalytic Activity and Potential Antibacterial Properties of Titanium Implants: Aya Ali1; Amol Janorkar1; Mary Marquart1; Jason Griggs1; Joel Bumgardner2; Michael Roach1; 1University of Mississippi Medical Center; 2University of Memphis
Silver is widely used as an antimicrobial agent due to its efficiency against resistant bacteria. This study hypothesized that silver doping titanium anodization oxide layers results in enhanced photocatalytic activity (PCA) and potentially improved antimicrobial activity. Three acid-based electrolytes previously shown to form crystalline titanium oxide layers exhibiting excellent PCA, were utilized with and without AgNO3 additions to anodize CPTi specimens to 180V final forming voltage. X-ray photoelectron spectroscopy revealed silver incorporation into each AgNO3 oxide group. The surface morphology, crystallinity, surface chemistry, and wettability of each oxide were investigated. PCA was also evaluated using a methylene blue degradation assay under 365nm UVA illumination. Two AgNO3 oxides showed increased rutile phase formation within the oxides compared to their counterparts produced in the same electrolytes without AgNO3 additions. T-tests revealed the same two AgNO3 oxides also showed significantly enhanced PCA after 240 minutes compared to their non-AgNO3 counterparts (p< 0.05).
8:30 AM
Biodegradable Ceramic Coating on Lithium-Aluminum-Zinc (LAZ) and Lithium- Zinc (LZ) Magnesium Alloys Using Micro-arc Oxidation: Prashant Kumta1; John Ohodnicki1; Abhijit Roy1; 1University of Pittsburgh
Biodegradable magnesium-based alloys containing lithium, aluminum, and zinc (LAZ) exhibit ultra-high ductility, but are limited in their use as a biodegradable bone scaffold due to rapid corrosion and consequent prevalence of increased cytotoxicity. The presence of multiple phases within the LAZ containing magnesium alloys also results in increased galvanic corrosion. The goal of this work was to reduce the corrosion rate of the LAZ magnesium-based alloys in order to increase their effectiveness as biodegradable biomaterials.Micro-arc oxidation (MAO) treatment using electrolyte containing fluorides, phosphates, and silicates form a corrosion resistant layer on the surface of these alloys. The deposited coating was characterized by XRD, SEM, and FTIR. Potentiodynamic polarization tests and in-vitro immersion testing confirmed that the MAO coatings significantly decreased the corrosion rate and overall release of metallic ions. In-vitro cytocompatibility studies revealed that MAO coated alloys also exhibited increased cell attachment and proliferation.
8:50 AM
Novel Biodegradable Porous Magnesium Alloy Scaffolds for Critical Sized Calvarial Bone Defect Reconstruction: Prashant Kumta1; Abhijit Roy1; Mubin Aral1; Matthew Criado1; John Ohodnicki1; Fatih Zor2; Vijay Gorantla2; Alejandro Almarza1; MaCalus Hogan1; 1University of Pittsburgh; 2Wake Forest University
Bone reconstruction of large area critical-sized calvarial bone defects in the craniomaxillofacial (CMF) region is clinically challenging. Resorbable and non-resorbable materials used for calvarial grafts often exhibit bone resorption, infections, inflammation and suboptimal osseointegration. Biodegradable magnesium (Mg) and Mg alloys are promising for CMF applications. However, there are no studies demonstrating the local and systemic toxicity of these alloys in a critical sized craniofacial model, particularly, when the implant is in physical contact with the periosteum. A new biodegradable Mg alloy based cranial bone graft (MgCBG) is presented demonstrating in vivo safety and efficacy as well as biomechanical stability when placed in the rat calvarial critical sized bone defect model. Results indicate that the developed MgCBG slowly degrades over 26 weeks forming new bone devoid of any local/systemic toxicities. The MgCBG also exhibit better bone regeneration and osseointegration compared to surgical grade poly-ether-ether ketone-based graft.
9:10 AM
In Vitro Biochemical Analysis of Bioactive Glass Ionomer Cement (45S5) with Citric Acid as Setting Modifier: Muhammad Uddin1; 1DOW University of Health Sciences (DUHS)
Objective: Aim of study was to produce a series of aluminum ions free silicate based bioactive glasses with substitution of calcium with strontium and barium (46.14 SiO2.2.60 P2O5.23.95 CaO.24.35 Na2O.1.5X1.1.5X2 (X1= SrO and SrF2) and (X2= BaO and BaF2) to analyse biological & mechanical properties of GIC based on modified bioactive glasses. Methods: Series of silicate based bioactive glasses were synthesised using melt quenching technique, incorporated in the synthesis of GIC after introduction of citric acid as setting modifier with admixture of poly-acrylic acid and water. Prepared glass samples were characterised physically by using XRD. Synthesised citric acid-based cement samples were further characterised based on their chemical, biological and mechanical properties using Raman, FTIR, MTT assay, Compressive strength measurement and Gilmore needle test respectively. Results:It is concluded that all prepared GIC samples exhibit improvement in biological & mechanical properties, can significantly be used in both medical and dental applications.
9:30 AM
Bioactive Polyelectrolyte Layer by Layer Assembled Corrosion Resistant Coatings on Surface Treated MgAZ31 Alloys: Prashant Kumta1; Sangeetha Kunjukunju1; John Ohodnicki1; Abhijit Roy1; Boeun Lee1; Joe Candiello1; 1University of Pittsburgh
Polyelectrolyte layer by layer (LbL) coatings on pretreated MgAZ31 substrates were prepared under physiological conditions to improve bioactivity and corrosion resistance. Pretreatment of MgAZ31 was achieved using alkaline and fluoride media methods. LbL-film assembly comprised of an initial polyethyleneimine layer followed by poly (lactic-co-glycolic acid) and poly(allylamine hydrochloride), that self-assemble via electrostatic interactions on the pretreated MgAZ31 surface. The LbL-films were characterized by FTIR, XRD, SEM, and AFM to analyze their physicochemical characteristics, surface morphologies, and microstructures. Electrochemical impedance spectroscopy measurements indicate that pretreated and LbL-coated substrates improved corrosion resistance of bare MgAZ31. Cytocompatibility studies using hMSC cells seeded directly on the substrates showed that the pretreated and LbL coated substrates are more cytocompatible and less cytotoxic than bare MgAZ31. Lastly, sustained release of BSA from the LbL-coated substrates was demonstrated reflecting the potential of using LbL coatings on magnesium-based scaffolds to enhance their surface bioactivity.
9:50 AM Break
10:10 AM
Exploring the Potential of Strontium Substituted Amorphous Calcium Phosphate and Dicalcium Phosphate Dihydrate Based Hydroxyapatite Forming Bone Cement: Prashant Kumta1; John Ohodnicki1; Abhijit Roy1; 1University of Pittsburgh
Hydroxyapatite (HAp) bone cements are ubiquitous as biodegradable bone tissue engineering scaffolds. This is because of their 1. chemically similarity to the mineralized matrix of natural bone; 2. High stability in physiological environments; and 3. degradation without eliciting any toxicity. However, HAp cements typically display slow degradation rates and clinically undesirable long setting times. An amorphous calcium phosphate (ACP) and dicalcium phosphate dihydrate (DCPD) based cement is presented to address this issue including the influence of Strontium (Sr) on the HAp forming cement characteristics. XRD and SEM was utilized to characterize the synthesized precursor powders and the final cement phase composition. Compressive strength and percent porosity of the as-set and after aged cement was also assessed. Results conclude that increased amounts of Sr facilitate a more rapid HAp phase transformation coupled with increased MC3T3 in-vitro cell attachment and viability. Results of these studies will be presented and discussed.
10:30 AM
Hydroxyapatite Loaded with 2-heptylcyclopropane-1-carboxylic Acid Inhibits S. Aureus Biofilm Formation: Emily Montgomery1; Isabella Bianca Reaņo1; Rachel Wiley1; Daniel Baker1; J. Amber Jennings1; 1The University of Memphis
Hydroxyapatite is a natural mineral component of tissue and often used in synthetic biomaterials for its bone-like mechanical and chemical properties. Non-antibiotic methods for infection prevention, such as the use of short chain fatty acid signaling molecules like 2-heptylcyclopropane-1-carboxylic acid (2CP), are advantageous. In this study, 2CP was loaded onto hydroxyapatite coupons to assess the effect on microbial planktonic growth and biofilm formation. 2CP was dissolved in ethanol and deposited on hydroxyapatite coupons. After 3 days of immersion in PBS with daily media changes, Staphylococcus aureus was added to coupons and incubated at 37°C for 24h. The coupons were removed and washed three times in sterilized phosphate buffered saline (PBS) before sonication in PBS to detach biofilm. Microbial viability for each group was quantified using Bactiter-Glo viability assay, which revealed a significant reduction in planktonic growth, biofilm on the coupons, and biofilm on the well plates (p<<0.001).