Accession Number : ADA615341


Title :   Biocompatibility and Chemical Reaction Kinetics of Injectable, Settable Polyurethane/Allograft Bone Biocomposites


Descriptive Note : Journal article


Corporate Author : ARMY INST OF SURGICAL RESEARCH FORT SAM HOUSTON TX


Personal Author(s) : Page, Jonathan M ; Prieto, Edna M ; Dumas, Jerald E ; Zienkiewicz, Katarzyna J ; Wenke, Joseph C ; Brown-Baer, Pamela ; Guelcher, Scott A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a615341.pdf


Report Date : 05 Aug 2012


Pagination or Media Count : 13


Abstract : Injectable and settable bone grafts offer significant advantages over pre-formed implants due to their ability to be administered using minimally invasive techniques and to conform to the shape of the defect. However, injectable biomaterials present biocompatibility challenges due to the potential toxicity and ultimate fate of reactive components that are not incorporated in the final cured product. In this study the effects of stoichiometry and triethylenediamine (TEDA) catalyst concentration on the reactivity, injectability, and biocompatibility of two component lysine-derived polyurethane (PUR) biocomposites were investigated. Rate constants were measured for the reactions of water (a blowing agent resulting in the generation of pores), polyester triol, dipropylene glycol (DPG), and allograft bone particles with the isocyanate- terminated prepolymer using an in situ attenuated total reflection Fourier transform infrared spectroscopy technique. Based on the measured rate constants, a kinetic model predicting the conversion of each component with time was developed. Despite the fact that TEDA is a well-known urethane gelling catalyst, it was found to preferentially catalyze the blowing reaction with water relative to the gelling reactions by a ratio 17:1. Thus the kinetic model predicted that the prepolymer and water proceeded to full conversion, while the conversions of polyester triol and DPG were 70% after 24 h, which was consistent with leaching experiments showing that only non-cytotoxic polyester triol and DPG were released from the reactive PUR at early time points. The PUR biocomposite supported cellular infiltration and remodeling in femoral condyle defects in rabbits at 8 weeks, and there was no evidence of an adverse inflammatory response induced by unreacted components from the biocomposite or degradation products from the cured polymer.


Descriptors :   *BIOMATERIALS , *BONES , *CHEMICAL REACTIONS , *POLYURETHANE RESINS , COMPATIBILITY , COMPOSITE MATERIALS , COMPUTERIZED TOMOGRAPHY , CYTOTOXINS , ETHYLENEDIAMINE , HISTOLOGY , INJECTION , KINETICS , PARTICLES , POLYESTER PLASTICS , POROSITY , PROPYLENE GLYCOL , REACTIVITIES , STOICHIOMETRY , SURGICAL TRANSPLANTATION , TOXICITY , WATER , WOUNDS AND INJURIES


Subject Categories : Biology
      Medicine and Medical Research
      Medical Facilities, Equipment and Supplies
      Polymer Chemistry
      Plastics


Distribution Statement : APPROVED FOR PUBLIC RELEASE