In situ formation of hydrogels as vitreous substitutes: Viscoelastic comparison to porcine vitreous.

The human vitreous is a gelatinous substance predominantly composed of water (97-99%). Vitreous substitutes are needed for treatment of retinal detachments by reapproximating the retina to the back of the eye, or during vitrectomies for maintenance of ocular volume. None of the current substitutes can be used long-term due to their short retention time, toxicity, or complications such as glaucoma or cataracts. In addition, all of the current compounds have a specific gravity less than water and so are not appropriate for inferior retinal detachments. The viscoelastic properties of the porcine vitreous were analyzed to develop a model for ideal substitutes. Synthetic polymers that form hydrogels in situ were researched for the development of artificial vitreous. In this study, the physical, mechanical, and optical properties of four self-gelling polyacrylamide copolymeric hydrogels were determined and compared with those of the porcine vitreous. The 2% formulation of high crosslink density, hydrophobically modified hydrogel most closely mimicked the porcine vitreous. The viscoelastic properties of hydrogels capable of being formed in situ were compared to those of the porcine vitreous to determine their efficacy as vitreous substitutes.

[1]  Nathan Ravi,et al.  Recent advances in polymeric vitreous substitutes , 2007 .

[2]  S. Suri,et al.  In vitro evaluation of in situ gels as short term vitreous substitutes. , 2006, Journal of biomedical materials research. Part A.

[3]  N. Ravi,et al.  Internal Osmotic Pressure as a Mechanism of Retinal Attachment in a Vitreous Substitute , 2006 .

[4]  Julia A. Kornfield,et al.  Internal Tension: A Novel Hypothesis Concerning the Mechanical Properties of the Vitreous Humor , 2005 .

[5]  J. Kornfield,et al.  A “cleat” geometry for suppressing wall slip , 2005 .

[6]  N. Ravi,et al.  Synthesis of Polyacrylamide Nanogels by Intramolecular Disulfide Cross-linking , 2005 .

[7]  N. Ravi,et al.  Refilling of ocular lens capsule with copolymeric hydrogel containing reversible disulfide. , 2005, Biomacromolecules.

[8]  N. Ravi,et al.  Biocompatibility of thiol-containing polyacrylamide polymers suitable for ophthalmic applications , 2004 .

[9]  N. Ravi,et al.  Towards the development of an artificial human vitreous , 2004 .

[10]  J. Hooymans,et al.  Age-related liquefaction of the human vitreous body: LM and TEM evaluation of the role of proteoglycans and collagen. , 2003, Investigative ophthalmology & visual science.

[11]  R. Banerjee,et al.  Artificial vitreous replacements. , 2003, Bio-medical materials and engineering.

[12]  S. Wu,et al.  Adler's Physiology of the Eye , 2002 .

[13]  R. Nuijts,et al.  Biodegradable three-dimensional networks of poly(dimethylamino ethyl methacrylate). Synthesis, characterization and in vitro studies of structural degradation and cytotoxicity. , 2000, Biomaterials.

[14]  T. Chirila,et al.  Poly(1-vinyl-2-pyrrolidinone) hydrogels as vitreous substitutes: a rheological study , 1998 .

[15]  Traian V. Chirila,et al.  The Vitreous Humor , 1998 .

[16]  Paul D. Dalton,et al.  THE USE OF HYDROPHILIC POLYMERS AS ARTIFICIAL VITREOUS , 1998 .

[17]  Jonathan Black,et al.  Handbook of Biomaterial Properties , 1998, Springer US.

[18]  I J Constable,et al.  Synthetic Polymers as Materials for Artificial Vitreous Body: Review and Recent Advances , 1994, Journal of biomaterials applications.

[19]  M. Litt,et al.  Rheology of the vitreous body: Part 2. Viscoelasticity of bovine and porcine vitreous. , 1994, Biorheology.

[20]  G. Buchsbaum,et al.  Rheology of the vitreous body. Part I: Viscoelasticity of human vitreous. , 1992, Biorheology.

[21]  D. Smith,et al.  Evaluation of antiproliferative agents using a cell-culture model. , 1990, Investigative ophthalmology & visual science.

[22]  P. Leaver.  Complications of Silicone oil , 1986 .

[23]  M. Stirpe,et al.  Basic and Advanced Vitreous Surgery , 1986, FIDIA Research Series.

[24]  M Tokita,et al.  Dynamic viscoelasticity of bovine vitreous body. , 1984, Biorheology.

[25]  C. Riva,et al.  Dynamics of an oscillating viscoelastic sphere: a model of the vitreous humor of the eye. , 1984, Biorheology.

[26]  M. Refojo,et al.  VITREOUS SUBSTITUTE: Experimental Studies and Review , 1984, Retina.

[27]  R. Zimmerman.  In vivo measurements of the viscoelasticity of the human vitreous humor. , 1980, Biophysical journal.

[28]  F. Bettelheim,et al.  Dynamic viscoelastic properties of bovine viterous. , 1976, Experimental eye research.

[29]  I. Churchill-Davidson,et al.  Oxygenation in radiotherapy. II. Clinical application. , 1957, The British journal of radiology.