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

Report Date:

2012-08-05

Pagination or Media Count:

13.0

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 171. 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.

Subject Categories:

  • Biology
  • Medicine and Medical Research
  • Medical Facilities, Equipment and Supplies
  • Polymer Chemistry
  • Plastics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE