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

Wednesday 3:40 PM
March 1, 2017
Room: Mission Hills
Location: Marriott Marquis Hotel

Session Chair: Carlos Schvezov, Instituto de Materiales de Misiones .- IMAM; Horacio Espinosa, Northwestern University

3:40 PM  Invited
Synthesis of Fish Scale Extracted Hydroxyapatite and Chitosan Composite Scaffolds by Freeze Casting for Biomedical and Environmental Applications: Wen-Kuang Liu1; Bor-Shuang Liaw1; Haw-Kai Chang1; Po-Yu Chen1; 1National Tsing Hua University
    Fish scales are typically considered as wastes in fishery industries yet important collagen and hydroxyapatite sources. In this study, hydroxyapatite minerals were extracted from scales of Tilapia fish (Oreochromis mossambicus) and utilized as raw materials for scaffolds synthesized by freeze casting technique. Chitosan was further coated on the hydroxyapatite scaffolds, forming bio-mineral/polymer composites. Microstructural features of scaffolds were characterized by SEM and micro-CT, revealing uniform laminar structures with 10-80 μm channels depending on cooling rates. The scaffolds were suitable for cell migration and growth, meanwhile exhibited good mechanical strength. In vitro test was done by culturing human osteoblast cells on the scaffolds, and cell viability was evaluated by MTS assay. The other application was the capability to remove heavy metal ions from waste water, which was quantified by Atomic Absorption Spectrometer. The fish scale derived hydroxyapatite/chitosan scaffolds have great potential to be applied in various fields.

4:10 PM  
Chemical Composition Effect of Sol-gel Derived Bioactive Glass Over Bioactivity Behavior: Lindsey Quintero1; Diana Escobar1; 1Universidad de Antioquia
    Bioactive glasses (BG) are a group of inorganic materials widely used in Bone Tissue Engineering (BTE). These biomaterials react with body fluids resulting in the formation of bone like apatite layer. In this study, sol-gel derived bioactive glass was synthesized in the SiO2-CaO-P2O5 system according to augmented restricted mixture experimental design, with percentage restrictions for each oxide as follows: 58 ≤ SiO2 ≤ 70; 6 ≤ P2O5 ≤ 9 and 24 ≤ CaO ≤ 34. BG were conformed into short-bulk cylinder and immersed in Simulated Body Fluid (SBF) solution for 7 and 14 days in order to carry out bioactivity tests. Apatite layer formation was confirmed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Analysis (EDX). The results showed apatite layer formation depended on BG chemical composition. The formed apatite layer presented a Ca/P ratio similar to Bone apatite, this result is appropriate for biomaterials used in BTE.

4:30 PM  
Injectability Evaluation of Bone-graft Substitutes Based on Carrageenan and Hydroxyapatite Nanorods: Jazmín González Ocampo1; Claudia Ossa Orozco1; 1University of Antioquia
    the first injectable bone substitutes were introduced for orthopedic trauma applications since more than a decade, and over recent years the number of commercial products has dramatically increased. These substitutes can be injected into a fracture space for augmentation as an alternative to bone graft, or around a screw for augmentation if the bone is weak, so the injectability of the substitute must be optimum with a good behavior within and our of syringe. The aim of this work was to study the injectability of substitutes based on carrageenan with 1, 1.5, 2.5wt% and 60wt% hydroxyapatite nanorods. Initially carrageenan and hydroxyapatite were characterized and then injectability tests were performed with the syringe between the compression plates of a testing machine. The results revealed that none of the samples had phases separation and they did not exceed 300N of force, therefore the substitutes are adequate for manual handling.

4:50 PM  
Comparative Analysis of Neural Cell Behaviour on Carbon Nanofiller Reinforced Polymeric Substrates: Pallavi Gupta1; Murali Kumaraswamy1; Partha Roy1; Debrupa Lahiri1; 1IIT Roorkee
    Since last decade, carbon nanomaterials such as carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) have gained remarkable popularity as substrate for neural tissue engineering. It has already been demonstrated that carbon nanomaterials possess ability to guide neurites to extend along the direction of alignment, resembling native hierarchy of neural tissue. In this study, HT-22 hippocampal neurons were used to investigate interactions of neurons with carbon nanofillers reinforced casted chitosan scaffolds. It was confirmed that the neurons show shape dependency on CNT and GNP reinforced scaffold, owing to electrical conductivity of scaffolds and shape of reinforced carbon nanofillers. Tensile properties and electrical conductivities of fabricated scaffolds were also characterized. Further, the effect of CNT and GNP alignment inside chitosan scaffold was also assessed on mechanical, electrical and biological activity of the scaffolds. Results prove that the carbon nanofiller reinforced chitosan scaffolds provide new guidelines for designing the well-defined neuronal network architecture.

5:10 PM  
Comparative Spectroscopic Studies on the Interaction of Nickel Selenide Quantum Dots with Serum Albumins: Selvaraj Naveenraj1; Ramalinga Mangalaraja1; Thangaraj Pandiyarajan1; Sambandam Anandan2; 1University of Concepcion; 2National Institute of Technology Trichy
    Nickel selenide (NiSe) quantum dots (QDs) of size less than 5 nm were successfully synthesized by a simple microwave process in the ethylene glycol medium using inexpensive precursors such as nickel chloride, sodium selenite, hydrazine (reducing agent) and starch (capping agent). Thus synthesized NiSe QDs were characterized using UV–vis spectroscopy, X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and energy-dispersive X-ray spectroscopy (EDS). Their in-vitro interactions with human serum albumin (HSA) and bovine serum albumin (BSA) were investigated using UV-vis, and fluorescence spectroscopic techniques. The spectral results confirmed that NiSe QDs quenched the fluorescence of serum albumins through static quenching mechanism and the fluorophore site is near the tryptophan moiety of serum albumins. The binding constant Kb obtained in the fluorescence studies indicated that NiSe QDs have more affinity towards HSA than that of BSA. These results will shed light towards the understanding of the NiSe QDs pharmacokinetics.