Biomimetic aggrecan solutions show gel-like rheological behavior

Abstract

Event Abstract Back to Event Biomimetic aggrecan solutions show gel-like rheological behavior Liam Vesey1, Harsh Patel1, Michele Marcolongo1 and Nicolas Alvarez1 1 Drexel University, Materials Science and Engineering and Chemical and Biological Engineering, United States Several cellular based medicine strategies exist to treat degenerative tissue and restore normal function. Over the past few years, it has been demonstrated that a novel family of biomimetic proteoglycans (BPs) is useful in modulating tissue mechanical properties by molecularly engineering the existing extracellular matrix. Biomimetic proteoglycans mimic the structure and composition of natural proteoglycans through a 3D bottle brush molecular architecture. The BPs of interest are composed of a poly(acrylic) acid core with bristles of chondroitin sulfate (CS) (BA-10-CS, 180kDa). We have observed that the starting CS precursor forms viscous solutions at low concentrations. Similar viscosities are also observed for solutions of synthesized BP. We present a systematic study of the rheological behavior of aqueous solutions of the CS precursor and final BPs as a function of aqueous concentration. We use small amplitude oscillatory shear (SAOS) on a DHR-3 rheometer to elucidate the underlying molecular structure of the bulk aqueous solution. Surprisingly, we find that both CS and BP show viscoelastic behavior typical of a gel and atypical for a solution of short chains. The observed rheological viscoelastic behavior is weakly dependent on CS and BP concentration. Furthermore, very little difference is observed between the CS precursor and the BP molecule. Our results suggest that CS molecules, which are composed of several acrylic acid and primary amine groups capable of hydrogen bonding, are forming a supramolecular network that span the sample volume. This is in agreement with other hydrogen bonding systems found in the literature. The surprising point is that the anchoring of CS molecules onto a poly(acrylic) acid core does not appear to alter the overall supramolecular structure. In addition to SAOS, the molecular structure of the CS aggregates are probed using large amplitude oscillatory shear and steady shear to determine the overall strength of the network and reformation time scales. The rheological study is presented alongside practical injection studies aimed at determining viability for injection of through needles between 16 and 33 gage under a controlled load of 1.8 N (less than thumb pressure to the plunger). Volumetric flow rates were calculated from video images of BP solutions of concentrations between 10 and 200mg/mL. Each solution was able to pass through each needle, regardless of solution concentration, material and needle gage. There was reduced volumetric flow rates for the higher concentrations and lower gage needles. The demonstration of flow through large to very small needles will offer minimally invasive injection strategies to a variety of soft tissues. Coulter Foundation Keywords: Biomimetic, mechanical property, polymer brush, biomacromolecule Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Naturally-derived materials and biopolymers Citation: Vesey L, Patel H, Marcolongo M and Alvarez N (2016). Biomimetic aggrecan solutions show gel-like rheological behavior. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.01381 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Liam Vesey Harsh Patel Michele Marcolongo Nicolas Alvarez Google Liam Vesey Harsh Patel Michele Marcolongo Nicolas Alvarez Google Scholar Liam Vesey Harsh Patel Michele Marcolongo Nicolas Alvarez PubMed Liam Vesey Harsh Patel Michele Marcolongo Nicolas Alvarez Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.