Collagen–phosphorylcholine interpenetrating network hydrogels as corneal substitutes

Controlled Release of Acyclovir Through Bioengineered Corneal Implants with Silica Nanoparticle Carriers~!2009-08-29~!2010-01-05~!2010-03-18~!

“…Hence, incorporation of carriers into a retentive ophthalmic ointment [19] or into contact lenses [22] have been proposed as means of extending drug availability to the ocular surface. However, to remedy HSV-induced vision loss, instead of treating the cornea with drugs and performing allograft surgery as two separate modalities, both with limited success rates, our results indicate that it would be possible to incorporate the drug/carrier directly into biosynthetic substitutes of human donor corneas [11,12], to allow for the drug to be released after implantation to prevent viral re-activation and re-infection. Incorporating the drug into a graft would circumvent drug availability issues to all the corneal layers.…”

“…More recently, we enhanced the mechanical strength and biostability of such collagen hydrogels by incorporating a second crosslinked polymeric network based upon a synthetic phospholipid, 2-methacryloyloxyethyl phosphorylcholine (MPC). These interpenetrating networks of collagen showed an increase in mechanical strength over crosslinked collagen alone, and an increased stability against enzymatic degradation while retaining their ability to promote regeneration of both corneal cells and nerves [12]. The increased stability in a hostile environment of high enzymatic activity commonly found in HSV-infected corneas is important for implant retention and viability.…”

“…Collagen-MPC hydrogels were prepared as previously described [12]. Briefly, 400 mg of 20 % (w/w) porcine type I acidic atelocollagen solution was buffered with 150 l of 0.625 M MES buffer in a syringe mixing system.…”

Corneal Tissue Engineering: Recent Advances and Future Perspectives

“…33 Further efforts have been undertaken to develop in vitro corneal stroma equivalents, in combination with the engineering of the epithelial layer and promoting nerve ingrowth, which ultimately culminated in engineered full-thickness cornea for tissue replacement, based on type I collagen in combination with a variety of synthetic polymers (e.g., polyacrylamide, poly(ethylene glycol)). [82][83][84][85] Biosynthetic corneas from cross-linked recombinant human collagen type III were implanted in an anterior partial keratoplasty surgery in human patients, to enhance endogenous tissue regeneration. The implants were stably integrated, innervated, and avascularized up to 2 years (Fig.…”

Artificial corneas: a regenerative medicine approach

“…25 Additional interpenetrating networks of biointeractive materials that retain stability in potentially adverse disease environments, for example, where high levels of enzymes are produced are also being developed. 26 Tissue-engineered scaffolds for stem and progenitor cell delivery…”