Advanced Biomaterials for Biomedical Implants and Biosensing Devices: Session II
Program Organizers: Tolou Shokuhfar, University of Illinois at Chicago; Sahar Vahabzadeh, Northern Illinois University

Monday 2:00 PM
September 30, 2019
Room: C120
Location: Oregon Convention Center

Session Chair: Tolou Shokuhfar, University of Illinois at Chicago; Sahar Vahabzadeh, Northern Illinois University

2:00 PM  
Improving the Biocompability and Corrosion Resistance of AZ31 Mg Alloy for Biomedical Applications: Adedotun Adetunla1; Esther Akinlabi1; 1University of Johannesburg
     Magnesium (Mg) and its alloys have been extensively researched recently for orthopaedic applications. Much advantages are seen with Mg alloys over economically available titanium and stainless steel implant. Recently, extensive mechanical characterization have been carried out to increase the biomedical performance of Mg Alloys via surface modification techniques and alloying method. Medical devices such as cardiovascular stents, wound closing devices and bone grafts have been made of magnesium alloy. However, magnesium alloy corrodes rapidly and also possess low biocompatibility hence its clinical applications are limited due to these drawbacks. In this study, Friction Stir Process was employed to produce AZ31 Mg by adding four different particle reinforcements to improve the corrosion resistance and biodegradable of magnesium alloys for biomedical applications. Both corrosion resistance and biocompatibility of magnesium alloy may be enhanced with the result obtained in this study which may subsequently increase the potential applications of Mg in biomedical devices.

2:20 PM  Cancelled
Extraction, Characterization and Properties of Chitin and Chitosan of Nigerian Origin: Chiosa Odili1; Oluwashinor Gbenebor1; Olatunde Sekunowo1; Oluropo Adeosun1; 1University of Lagos
     Isolation of chitin and chitosan are being intensified due to their usage in several applications. In this study, extraction of chitin and chitosan was carried out on crab shell using chemical method with 1.2M of HCl and 1M of NaOH at 100oC. This was followed by deacetylation of chitin to produce chitosan. The extracts were characterized using SEM, FTIR, DTA and XRD.The FTIR of chitin and chitosan reveal the absorption bands of 3460,3268,1660, 1558,1157 cm-1 and 3460,3267,3111,2931,1662,1628 ,696cm-1respectively. These compare well with the standard spectral for chitin and chitosan. The DTA plot shows that the degradation temperature of chitin and chitosan are 388oC and 342oC respectively. The micrograph of chitin and chitosan showed globules of rough crystals, and long thin structure respectively laying on a smooth elastic black surface, suggesting that they could form a fibre for suture, scaffold, fibrous mat, for biomedical application Keywords:Crab-shell, Chitin, Chitosan,Deacetylation,Demineralization

2:40 PM  
From Porous to Dense Nanostructured β-Ti Alloys through High-pressure Torsion: Advanced Characterization: Conrado Afonso1; Angelica Amigˇ2; Vladimir Stolyarov3; Ra˙l Arenal4; Vicente Amigˇ2; 1Universidade Federal de SŃo Carlos (UFSCar); 2Universitat PolitŔcnica de ValŔncia (UPV); 3Moscow Engineering Physics Institute ; 4Universidad de Zaragoza
    β-Ti alloys have low elastic modulus, good specific strength and high corrosion resistance for biomaterial applications. One method to refine the structure and improve mechanical properties is a severe plastic deformation technique through high-pressure torsion (HPT). The aim of this work was to evaluate the conversion of powder metallurgy P/M porous β-Ti-35Nb-10Ta-xFe alloys to dense nanostructures through high-pressure torsion in one deformation step and the influence of the structure variation on the properties and microstructure. TEM analysis and ASTAR crystallographic mapping was utilized to characterize the nanostructures, and the properties of P/M β Ti-35Nb-10Ta-xFe alloys processed by HPT were compared. This work includes correlative microscopy of structure, composition (EDS and EELS) and elastic modulus mapping (through EELS) at nanoscale of HPT processed Porous PM β-Ti alloy. The HPT process refined the microstructure from 50 Ám (P/M) down to nanostructured grains of approximately 50 nm.

3:00 PM  
Zinc Doping Controlled In Vivo Degradability of Magnesium Phosphate Bioceramic: Kaushik Sarkar1; Vinod Kumar2; Samit Nandi2; Mangal Roy1; 1Indian Institute of Technology; 2West Bengal University of Animal & Fishery Sciences
    In this presentation we will discuss the comparison of in vitro and in vivo degradation behaviour and biocompatibility of pure and Zn (0.25 & 0.5wt%) doped magnesium phosphate (MgP) bioceramic. Samples were prepared by solid state sintering at 1200║C. Degradation studies in SBF upto 8 weeks showed control release of Mg2+ ions. Alamar blue assay and Live/Dead imaging showed highest cell attachment and proliferation for 0.5wt.%Zn doped MgP. Á-CT analysis showed that in vivo degradability increased with increase in Zn conent which is in contradiction to in vitro degradability. Histology showed large influx of osteoclast cells to the implantation site for Zn doped MgP compared to that of pure MgP, which is primary reason of increased degradability. After 90 days of implantation, large sections of 0.5wt.%Zn doped MgP samples were replaced by new bone.

3:20 PM Break

3:40 PM  
Plasma sprayed in-situ formed TiB-TiN reinforced Ti6Al4V alloy composite coatings: Tribocorrosion evaluation: Akrity Anand1; Mitun Das1; Biswanath Kundu1; Subhadip Bodhak1; Gangadharan S1; Vamsi Balla2; 1CSIR-Central Glass & Ceramic Research Institute; 2University of Louisville
    Herein we report plasma deposition of in-situ synthesized TiB-TiN reinforced Ti6Al4V alloy composite coatings and their bio-tribocorrosion performance for wear resistance implant applications. The influence of plasma power (50 and 60kW) and deposition speed (40 and 50mm/s) on the microstructure and bio-tribocorrosion performance of these composite coatings was analyzed. Microstructural analysis showed that the in situ reaction is complete with some TiO2. Tribocorrosion tests in Hank’s balanced salt solution revealed that the effect of corrosion on wear is more than vice versa. Further, it appears that formation of corrosion products on composite coatings protects them against tribocorrosion induced damge. Increase in the deposition speed and/or decrease in the plasma power found increase pure mechanical wear and corrosion loss of coatings. Our results demonstrate that plasma sprayed, in-situ formed TiB-TiN reinforced Ti alloy composite coatings offer superior tribocorrosion resistance than Ti substrate due their non-passivating nature and high hardness.

4:00 PM  
Effect of Heat Treatment and Forging on In Vitro Corrosion and Cytocompatibility of Mg-Zr-Sr-Ce Alloy: Sourav Dutta1; Sanjay Gupta1; Mangal Roy1; 1Indian Institute of Technology Kharagpur
    Biodegradable magnesium based alloys are considered as smart implants for orthopaedic applications. In this presentation we will discuss about the effects of heat treatment and forging on mechanical properties, in vitro corrosion and cytocompatibility of Mg-Zr-Sr-Ce alloy. The mechanical properties of heat treated and forged (HT&F) alloy was significantly higher than as cast (C) and heat treated (HT) condition. The HT&F samples showed 42 and 5.6 times higher corrosion resistance than C and HT alloy owing to its fine grain and uniform distribution of second phase particles. Micro-CT analysis revealed minimal increase in porosity for HT&F alloy after 168h of immersion in PBS. In vitro cytocompatibility studies indicated that HT&F alloy had good cell adhesion and proliferation. Overall, the HT&F Mg-1Zr-2Sr-1.5Ce showed favourable mechanical, corrosion and cytocompatibility which make it a potential candidate for degradable implant applications.