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Microscopic observations of superficial ultrastructure of unworn siloxane‐hydrogel contact lenses by cryo‐scanning electron microscopy
Author(s) -
GonzálezMéijome José M.,
LópezAlemany Antonio,
Almeida José B.,
Parafita Manuel A.,
Refojo Miguel F.
Publication year - 2006
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.30386
Subject(s) - scanning electron microscope , self healing hydrogels , materials science , siloxane , polymer , ultrastructure , contact lens , environmental scanning electron microscope , electron microscope , microscopy , optical microscope , lens (geology) , composite material , polymer chemistry , optics , anatomy , physics , medicine
The purpose of this study was to analyze three commercial siloxane‐hydrogel contact lens materials, lotrafilcon A, balafilcon A, and galyfilcon A, by cryogenic scanning electron microscopy (cryoSEM). The fully hydrated lenses were frozen in slush liquid nitrogen and qualitatively observed in a cryogenic scanning electron microscope. The superficial ultrastructure of the siloxane‐hydrogels was observed at the areas where the lens fractured during sample cryogenic preparation. There are qualitative differences among the three examined materials in the complex polymer network structure existing between the outer layer and the underlying polymer. CryoSEM, although destructive, is a useful tool to investigate the structure of polymers used in contact lenses. This technique allows the observation of the inner structure of polymers in the hydrated state. The ultrastructure, the polymer network underlying the outer surface of siloxane‐hydrogels by cryoSEM microscopy, have never been reported before. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006