A hydrogel is defined as the gel which contains water but is not soluble in water. Such hydrogels have been well-known for a long time, but it is just recently that the hydrogel has attracted much attention because of its novel properties. Hydrogels can be obtained in various ways. Among them are chemical crosslinking of PVA with aldehydes such as formaldehyde and glutaraldehyde, PVA crosslinking by irradiation with radiations such as gamma rays, electron beams, and ultraviolet light, PVA crosslinking through coordinate bonding with metal ions such as Ti, Cu, and Co, and PVA crosslinking with the use of boric acid, borax, and Congo Red. However, these proposed methods are not successful in obtaining the hydrated PVA gel which has both the high mechanical strength and the high water content. In other words, an increase in mechanical strength results in low water content, whereas a high water content leads to poor mechanical properties of the PVA gel.

The eyeSlices technology is based upon Poly(vinyl alcohol) (PVA) - a hydrophilic polymer which is of special interest for the application in medicine owing to its excellent biocompatibility. Poly(vinyl alcohol) is one of the most ancient polymers and at the same time the most popular one used in this field. It is manufactured through Freeze/thaw cycling of PVA polymer in solution resulting in the formation of physical cross-linking (i.e. weak bonding through a nonpermanent "association" of the polymer chains) Read More >