Glucose permeable poly (dimethyl siloxane) poly (N-isopropyl acrylamide) interpenetrating networks as ophthalmic biomaterials

Biomaterials. 2005 Jan;26(3):233-44. doi: 10.1016/j.biomaterials.2004.02.025.

Abstract

Poly (dimethyl siloxane) (PDMS) has been widely used as a biomaterial in ophthalmic and other applications due to its good compatibility, high mechanical strength, excellent oxygen permeability and transparency. However, for use as an artificial cornea, contact lens and in other applications, modifications with hydrophilic functional groups or polymers are necessary to improve wettability for tear protein and mucin interactions and to improve glucose permeability for cellular health. Poly (N-isopropyl acrylamide) (PNIPAAM) is a biocompatible and hydrophilic polymer that has been extensively studied on controlled drug release applications due to its lower critical solution temperature (LCST) phenomenon. In the current work, a composite interpenetrating network (IPN) of PDMS and PNIPAAM was formed to generate polymers with oxygen and glucose permeability as well as improved wettability compared to PDMS homopolymers and greater mechanical strength than PNIPAAM homopolymers. Transparent vinyl and hydroxyl terminated PDMS/PNIPAAM IPNs (PDMS-V and PDMS-OH IPNs, respectively) were successfully synthesized. Transmission electron microscopy images verified the structure of the IPNs. Surface analysis suggested that PNIPAAM was present on the surface as well as in the bulk material. PDMS-OH IPNs generated from a PDMS-OH matrix cured in the presence of solvent had the highest glucose permeability at 10(-7)cm2/s, comparable to that of the native cornea. The LCST phenomenon remained in these materials, although changes were not as abrupt as with pure PNIPAAM. These results suggest that these materials may be further developed as ophthalmic biomaterials or for controlled drug-release applications.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrylic Resins / chemistry*
  • Biocompatible Materials / chemistry*
  • Diffusion
  • Dimethylpolysiloxanes / chemistry*
  • Glucose / chemistry*
  • Materials Testing
  • Nylons / chemistry*
  • Ophthalmologic Surgical Procedures / instrumentation
  • Ophthalmologic Surgical Procedures / methods*
  • Osmotic Pressure
  • Permeability
  • Porosity
  • Surface Properties
  • Temperature
  • Tensile Strength
  • Water

Substances

  • Acrylic Resins
  • Biocompatible Materials
  • Dimethylpolysiloxanes
  • Nylons
  • poly(dimethylsiloxane)-polyamide copolymer
  • Water
  • poly-N-isopropylacrylamide
  • Glucose