Surface-Functionalized Model Contact Lenses with a Bioinspired Proteoglycan 4 (PRG4)-Grafted Layer

Abstract

Ocular dryness and discomfort are the primary reasons for the discontinuation of contact lens wear. This is mainly due to poorly hydrated contact lens surfaces and increased friction, particularly at the end of the day and can potentially cause reduced vision or even inflammation. Proteoglycan 4 (PRG4) is a mucinous glycoprotein with boundary lubricating properties, naturally found in the eye, able to prevent tear film evaporation and protect the ocular surface during blinking. Aiming to improve the interfacial interactions between the ocular surface and the contact lens, the synthesis and characterization of surface-modified model contact lenses with PRG4 is described. Full-length recombinant human PRG4 (rhPRG4) was successfully grafted onto the surface of model conventional and silicone hydrogel (SiHy) contact lenses via its somatomedin B-like end-domain using N, N'-carbonyldiimidazole linking chemistry. Grafting was assessed by Fourier transform infrared spectroscopy-attenuated total reflectance, X-ray photoelectron spectroscopy, and radioactive (I) labeling. Surface immobilization of rhPRG4 led to model conventional and SiHy materials with improved antifouling properties, without impacting optical transparency or causing any toxic effects to human corneal epithelial cells in vitro. The surface wettability and the boundary friction against human corneal tissue were found to be substrate-dependent, with only the rhPRG4-grafted model SiHy exhibiting a reduced contact angle and kinetic friction coefficient compared to the unmodified surfaces. Hence, clinical grade rhPRG4 can be an attractive candidate for the development of novel bioinspired SiHy contact lenses, providing improved comfort and overall lens performance.

BCLA CLEAR - Contact lens wettability, cleaning, disinfection and interactions with tears

“…It has also been used as a surface wetting agent in commercially available soft contact lenses [160]. Addition of PRG4 to hydrogel or SiHy lenses enhances their wettability and lubricity [70,161] as well as the kinetic coefficient of friction [72]. Incorporation of both HA and PRG4 to form an HA/PRG4 complex produces synergistic properties that reduces friction [159,162,163].…”

Modification of Silicone Hydrogel Contact Lenses for the Selective Adsorption of Ofloxacin

“…The FTIR spectra of the SL, MSL, and MIP/OFL-MSL contact lenses are shown in Figure 3. In Figure 3 a, the peak at 3340 cm −1 was assigned to an -OH bond [28]. The band around 2960 cm −1 could be attributed to the stretching vibration of C-H from silicone.…”

Recent Advances in New Copolymer Hydrogel‐Formed Contact Lenses for Ophthalmic Drug Delivery

“…As mentioned above, the non‐silicone based hydrogel CLs have an essential issue: low oxygen permeability, which can cause corneal hypoxia and result in “red blood filament” [19,61–63] . So the silicone monomers are taken into consideration for the reason that these silicone materials contain silicon which can enhance oxygen permeability of CLs [38] .…”