Tissue-protective hydrophilic polymer solutions and surface modifications

The occurrence of tissue damage is the source of serious postoperative complications in a wide range of surgical procedures. This damage is a result of tissue handling and adverse interfacial implant-tissue interactions. This research deals with different aspects of tissue damage and the use of hydrophilic polymers to minimize tissue trauma.; In cataract surgery, the use of intraocular lens (IOL) polymeric prosthesis to restore vision have gained widespread acceptance. More than 2,000,000 IOLs will be implanted in 1993. However, adverse hydrophobic interactions between IOLs and ocular tissues result into substantial tissue damage. The first part of this research involved the synthesis and characterization of hydrophilic surface grafts onto two primary IOL polymers, Polymethylmethacrylate (PMMA) and Polydimethysiloxane (PDMS), by radiation-induced polymerization. A novel approach to surface grafting using mixtures of N-vinylpyrrolidone (NVP) and polyvinylpyrrolidone (PVP) produced thin and highly stable hydrophilic grafts. Surface graft polymerization of some anionic vinyl sulfonic acid monomers onto PMMA and PDMS was also achieved. The preparation of composite hydrophilic grafts containing carboxymethylcellulose (CMC) and hyaluronic acid (HA) was described. Surfaces were characterized using gravimetric analysis, goniometry, Fourier transform infrared by attenuated total reflectance (FTIR/ATR), X-ray photoelectron spectroscopy (XPS), staining/light microscopy, and scanning electron microscopy (SEM). In vitro evaluation of hydrophilic surfaces revealed significantly reduced adhesion-induced tissue damage.; Another approach to minimizing tissue damage is the use of tissue-protective hydrophilic polymer solutions. In this context, the properties of carboxymethylcellulose (CMC) solutions were investigated and empirical equations relating concentration to rheological behavior were developed. Solution purification by filtration and autoclaving was described and subsequent changes in rheology characterized. The results suggested that rheological properties of CMC are may be due to the formation of stable intermolecular associations (junction zones).; Tissue damage can also cause postsurgical adhesions. The preparation and characterization of insolubilized CMC membranes as adhesion prevention devices was investigated. Insolubilization by ionic complexation and thermal treatment has produced CMC membranes with a wide range of properties.; In vivo evaluation in a rat cecal model revealed that CMC membranes significantly reduce the incidence and severity of peritoneal adhesion formation.