Biocompatibility of Polyvinylalcohol Gel as a Vitreous Substitute

Abstract

Polyvinylalcohol (PVA) hydrogel cross-linked by gamma irradiation was assessed as a possible vitreous substitute. From a series of experiments, rise of intraocular pressure and inflammatory changes in the vitreous cavity after operation were observed in some cases. Crab-eating macaques were used for this experiment. PVA gels were injected into vitreous cavity after vitrectomy and followed clinically by opthalmoscopy, tonometry, fundus photography, electroretinogram (ERG), chemotaxis, and flare cell meter. Histopathologic examination by light and electron microscopy was performed after 3 months. As a result, there were no significant changes in ophthalmoscopic findings. No abnormal rising of intraocular pressure (IOP) was recognized. ERG did not show meaningful amplitude weakness. From the photon counting of flare cell meter, significant break of blood-aqueous barrier and blood-retinal barrier was not observed. Histopathologic examination revealed that all layers of the retina were intact and no loss of tissue was evident. However, in PVA gel-injected eyes, some vacuolations of the inner retina were found in some specimens. To conclude, PVA gel was well tolerated in these experiments. The gel with a network similar to the vitreous body showed the best biocompatibility, though it is necessary to investigate the biocompatibility for the long-term. PVA gel is a good candidate for a vitreous substitute.

A new strategy to replace the natural vitreous by a novel capsular artificial vitreous body with pressure-control valve

“…These materials are still in experimental stages and their long-term toxicity is unknown. [9][10][11][12] Current research on artificial vitreous body aims to find materials, which are transparent, injectable, and biocompatible in vivo. Therefore, these materials must be hydrophilic and able to form a gel within the vitreous cavity.…”

The Use of Polymers in the Treatment of Retinal Detachment: Current Trends and Future Perspectives

“…Recently, Maruoka et al [185] prepared PVA hydrogels by treating the polymer solution in autoclave before γ-irradiation (like previously reported by Yamauchi et al) and injected the resulting gels into monkeys' eyes. During the first postoperative weeks inflammatory response and IOP increase was detected, but by 3 months after implantation the eyes regained normal IOP and retinal activity.…”

“…On the basis of data currently available in the literature and discussed in the previous sections, the author suggests that four synthetic polymers seem particularly suitable for prolonged vitreous tamponade and worthy of further investigations: PAA [166][167][168][169][170][171][172], PVA [183][184][185], PVA-MA [186] and SFAs [188][189][190]. Also, three other materials, HPMC [177,178], the cross-linked gelatins recently tested by Lai [152], and the gellan gum/hyaluronic acid gel proposed by Suri et al [159], exhibit interesting properties, but seem only useful for short-term vitreous substitution.…”

Evaluation of Antimicrobial Activity of Biosynthesized Iron and Silver Nanoparticles Using the Fungi Fusarium Oxysporum and Actinomycetes SP. on Human Pathogens

“…The unique combination of high magnetization and paramagnetic behavior opens these materials to a very wide range of applications. Greater availability of the surface area facilitates in biosensor [15], drug delivery [16] and tissue repair [17], MRI [18], hyperthermic effect [19], cell tagging and tracking [20], gene delivery [21,22], detection of probes [23,24], in agriculture, biosensor, rapid separation in environmental biology and concentration tracing of specific targets, such as bacteria, leukocyte and protein [25]. The metallic nanoparticles are most promising as they contain antibacterial properties due to their large ratio betwwen surface area and volume.…”