Bio-Nano Interfaces and Engineering Applications: Functional BionanoInterfaces
Sponsored by: TMS Functional Materials Division, TMS Structural Materials Division, TMS: Biomaterials Committee
Program Organizers: Candan Tamerler, University of Kansas; John Nychka, University of Alberta; Kalpana Katti, North Dakota State University; Terry Lowe, Colorado School of Mines

Wednesday 8:30 AM
March 1, 2017
Room: Pacific 21
Location: Marriott Marquis Hotel

Session Chair: Hendrik Heinz, University Of Colorado-Boulder; Sermin Utku, Yeditepe University

8:30 AM  
Engineering Hydrogels with Bioactive Nanomaterials for Bone Regeneration Applications: Settimio Pacelli1; Ryan Maloney1; Arghya Paul1; 1University of Kansas
    Non-union fractures and critical sized bone defects have great difficulty healing without intervention. Tissue engineering strategies aim to recreate bone’s natural healing processes on a fabricated scaffold with cells and therapeutics for implantation. One class of materials used for both therapeutics and in vitro modeling are hydrogels. However, the fragile mechanical properties of hydrogels limit their application in heavy load-bearing regions of bone. Inclusion of nanomaterials within the polymeric hydrogel network can both increase the strength of the network and allow exploitation of their unique abilities to interact with encapsulated cells and therapeutics. Here, we report that the inclusion of nanodiamonds, octahedral carbon-based biocompatible nanoparticles, can both improve the mechanical properties of gelatin-based hydrogels, enable dexamethasone loading and delivery to encapsulated human adipose-derived mesenchymal stem cells. In addition, we demonstrate multiple other biomedical applications of gelatin/nanodiamond based hydrogels, such as in delivery of biotherapeutics, microscale patterning and bioprinting.

9:00 AM  Invited
Toughness-Enhancing Linear Metastructure in the Recluse Spider’s Nanoribbon Silk: Hannes Schniepp1; 1The College of William & Mary
    The recluse spider spins high-aspect ratio silk ribbons unlike any other fiber, 6–8 μm wide and only 40–50 nm thin. In terms of stiffness and strength, these ribbons rival the highest-performing silks previously reported. Moreover, due to their extreme thinness, these ribbons can bend easily, facilitating surface conformation upon contact, thus introducing exceptionally strong adhesion. Using a unique spinning mechanism, the recluse spider uses organizes these ribbons into a linear metastructure of serial microloops. The loop junctions based on self-adhesion of the ribbon can sustain extremely high forces. The opening of such a sacrificial loop is non-destructive and releases hidden length, relaxing the fiber and restarting the stress–strain curve. This “strain cycling” substantially increases the toughness of the material, changing its tensile characteristics. We show that this stress–strain engineering via metastructure enables manifold toughness enhancements and demonstrated this in a synthetic, bio-inspired looped ribbon design.

9:40 AM  Keynote
Interfacing Freeze-Cast Biopolymer Scaffolds with Tissue In Vivo: Effects of Composition and Structure on Integration and Degradation: Prajan Divakar1; Karen Moodie1; P. Jack Hoopes1; Ulrike Wegst2; 1Dartmouth College; 2Dartmouth College
    While freeze-cast biopolymer scaffolds, made by directional solidification of an aqueous solution and lyophilization, have attracted considerable research attention for applications in soft tissue regeneration, surprisingly few studies have been published, to date, that report metrics on their in vivo biocompatibility and performance. Compared in this study are the effects of composition and structure on host tissue responses to freeze-cast scaffolds made from different biopolymers. Histology of the scaffolds and tissue-scaffold interfaces implanted subcutaneously in the body wall of mice was performed to study cell makeup and distribution, assess scaffold capabilities and structural properties, and quantify biomaterial encapsulation. Additionally, the systemic immune response was studied. The results obtained demonstrate the effectiveness of the murine model for scaffold biocompatibility testing and characterization. They are critical for the selection of biomaterials and their custom-design for a given application.

10:20 AM Break

10:40 AM  
Bio-Nano-Technology toward Smart Interfaces and Functional Hybrid Materials: Candan Tamerler1; 1University of Kansas
    There is proliferating interest in generating smart materials that incorporate or mimic biological functions built upon self-assembly and self-organization properties. Such bio-hybrid assemblies can be utilized within or outside of the original biological task enabling Nature`s repertoire to be expanded towards sustainable and green functional material processing. This requires designing entirely new interfaces and bio-hybrid pairs where the formation of higher order structures can be achieved while bringing exquisite control over orientation and spatial aspects. Mimicking biological machinery in Natural Materials, our group has been advancing bio-nano-interfaces resolving engineered biomolecules that allow as well as enhance favorable integrated interactions in the solid materials design. Our examples will include controlling the biological activity at soft-hard interfaces and the self-organization of engineered peptides conjugated to functional proteins, e.g. redox enzymes and fluorescence proteins to form controlled assemblies with single to multiple layer organization.

11:00 AM  
Characteristics of von Willebrand Factor Adhesion on Collagen Surface under Flow: Wei Wei1; Chuqiao Dong1; Michael Morabito1; Xiaohui Zhang1; Wei Zhang1; Yan Xu1; Wenli Ouyang1; xuanhong cheng1; Edmund Webb1; Alparslan Oztekin1; 1Lehigh University
    In injured arteries, fascinating bio-nano interfacial phenomena occur during blood clotting that are facilitated by the multimeric protein, von Willebrand Factor (VWF). In normal blood flow, VWF adopts globule conformations; near injury sites, hydrodynamic force from increased flow elongates VWF, exposing binding sites for collagen on the injured arterial surface. Herein we present results from molecular simulations - using parameters from single molecule force spectroscopy experiments - to study binding between VWF and collagen sites. Bond formation and rupture were described via Bell model kinetics and Brownian dynamics simulations were performed to understand VWF multimer adhesion in varying flow conditions. By implementing a binding condition dependent on molecular conformation local to the model VWF binding site, model adhesion predictions were brought into agreement with experimental observations, which show increased adhesion at higher flow rate. Molecular structure at the interface will be presented to help elucidate mechanisms governing VWF functionality.

11:20 AM  
Characterization of Solid-supported Thin Films and Molecular Interactions Using Multi-parametric Surface Plasmon Resonance: Annika Jokinen1; Niko Granqvist1; Janusz Sadowski1; 1BioNavis Ltd.
    Multi-parametric surface plasmon resonance (MP-SPR) utilizes full SPR angular spectral measurement at multiple wavelengths to characterize thin films properties. CVD-grown graphene films thickness and optical properties were determined. After the first initial layer thickness was found to be 0.37nm/monolayer [Jussila 2016]. Stearic acid (SA) LB-films showed approximately 2.50.2 nm thickness, and linear increment with increasing layer number [Granqvist 2013]. Additionally to layer properties MP-SPR measures interactions on thin films in real-time and without labels. Protein and cell samples binding on a Plasma Sprayed hydroxyapatite (HA) coating was measured [Vilardell 2016]. The non-invasive MP-SPR is proved to be an effective tool for the nanoscale metal, nanolaminate, oxide, polymer, and ceramic layers characterization in air and in liquid. Within the same measurement also material film interactions can be measured. Method high sensitivity makes MP-SPR NaviTM instruments great tool for thin films characterization.