Hydrogel nanocomposite as a synthetic intra-ocular lens capable of accommodation

A hydrogel nanocomposite was designed, synthesized, and evaluated for use as an auto-focusing intra-ocular lens. The hydrogel scaffold was composed of a monomer-free, thiol that contained polyacrylamide (5%), which was allowed to gel in the presence of nanoparticles at pH 7.4, 25°C. The nanoparticles consisted of a proteo-mimetic polyacrylamide nanogel (∼42 nm), bovine serum albumin (BSA) (∼6 nm), and hydrophilized silica (∼3 nm). The extent of nanoparticle loading increased with decreasing particle size. The elastic modulus increased with increasing loading of the proteo-mimetic nanogels and BSA, and it decreased with hydrophilized silica. In this investigation, the hydrogel that contained silica was the most promising class of nanocomposite hydrogels with properties comparable to that of a young porcine lens. A nanocomposite that consisted of 10% hydrogel scaffold and 24% hydrophilized silica (elastic [E] modulus of ∼1.0 kPa and refractive index [RI] of 1.42) was injected into a pre-evacuated porcine lens capsular bag. The composite lens was evaluated in a custom-designed four-arm radial stretcher, and its force-time spectrum was characterized by time constants of 60 ± 8.9 and 800 ± 32 ms. These results were comparable to a young porcine lens (E Modulus of 1.2 kPa; RI of 1.4105; time constants of 48.3 ± 0.58 and 668 ± 24.6 ms, respectively)