Surface and bio-adhesion properties of new hydrophobic and current materials for artificial intraocular lens

Poster (2012)

A high bio-adhesion appears to be one of the key factor for posterior capsular opacification (PCO) prevention. Indeed, the proteins adsorption and the lens epithelial cells (LEC) adhesion both contribute ... [more ▼]

A high bio-adhesion appears to be one of the key factor for posterior capsular opacification (PCO) prevention. Indeed, the proteins adsorption and the lens epithelial cells (LEC) adhesion both contribute to PCO development. We present in this work the comparison of a new glistening free hydrophobic material (GF® from Physiol) with benchmark hydrophobic and hydrophilic materials regarding their chemicophysical properties and their respective ability to interact with lens epithelial cells and proteins. For this purpose, we determined the hydrophobicity by contact angle measurement (assessed by water drop and air bubble methods), the surface adhesiveness by atomic force microscopy (AFM), the proteins adsorption by fluorescent measurement and the LEC adhesion by the determination of cell density. The new hydrophobic material presents comparable hydrophobicity, proteins adsorption and LEC adhesion to current commercial hydrophobic material. Its adhesiveness, measured with the AFM, is intermediate between hydrophilic and hydrophobic materials. In conclusion, the bio-adhesion properties of this new glistening free hydrophobic IOL material are similar to generic hydrophobic acrylic materials and therefore should to the same extent prevent PCO. [less ▲]

Hydrogel nanocomposites: a potential UV/blue light filtering material for ophthalmic lenses

in Journal of Biomaterials Science. Polymer Edition (2011), 22

Poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (poly(HEMA-co-MMA)) and ZnS hydrogel nanocomposites were prepared and characterized. The chemical composition of the inorganic nanoparticles was ... [more ▼]

Poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (poly(HEMA-co-MMA)) and ZnS hydrogel nanocomposites were prepared and characterized. The chemical composition of the inorganic nanoparticles was confirmed by X-ray diffraction, and the homogeneity of their distribution within the hydrogel was assessed by transmission electron microscopy. The influence of the content of ZnS nanoparticles on the optical performances of the nanocomposites was investigated by UV-Vis spectroscopy. The ability of the hydrogel nanocomposites to filter the hazardous UV light and part of the blue light was reported, which makes them valuable candidates for ophthalmic lens application. In contrast to the optical properties, the thermo-mechanical properties of neat poly(HEMA-co-MMA) hydrogels were found to be largely independent of filling by ZnS nanoparticles ( 2 mg/ml co-monomer mixture). Finally, in vitro cell adhesion test with lens epithelial cells (LECs), extracted from porcine lens crystalline capsule, showed that ZnS had no deleterious effect on the biocompatibility of neat hydrogels, at least at low content. [less ▲]

Polymers in modern ophthalmic implants—Historical background and recent advances

in Materials Science & Engineering : R (2010), 69(6), 63-83

Cataract surgery is the most frequently performed surgical intervention, pursued by replacement of the opacified natural lens by a polymeric intraocular lens (IOL). This paper, based on an exhaustive ... [more ▼]

Cataract surgery is the most frequently performed surgical intervention, pursued by replacement of the opacified natural lens by a polymeric intraocular lens (IOL). This paper, based on an exhaustive number of scientific references, provides a brief simplified discussion of the surgical advances for cataract treatment, and is mainly focused on the process of IOL discovery, engineering and development. The performances of the polymer materials, used for the IOLs fabrication are discussed in a comparative way, and their properties, such as handling during surgery, biocompatibility, rate of some post-surgical complications (e.g. Posterior Capsular Opacification) and optical properties, are considered. Special attention is paid on the basic scientific approaches for engineering and modification of the IOL surface and bulk properties. Polymer coating techniques like ‘grafting onto’ and ‘grafting from’ are discussed and exemplified by a variety of coating compositions and performances. In another part of the review, modification techniques concerning optimization of the bulk properties of the polymer lens are also discussed and synthetic approaches such as copolymerization and nanocomposite formation are considered. A perspective aspect of this discussion concerns improvement of the performance of the main polymer by the incorporation of in situ formed or preformed nanoparticles. The most attractive perspectives concerning the improvement of the IOL properties by chemical modification approaches are described. [less ▲]

Plasma surface fluorination of hydrogel materials-coating stability and in vitro biocompatibility testing

in Soft Materials (2010), 8(2), 164-182

Plasma enhanced chemical vapor deposition has been tested for the formation of hydrophobic perfluorinated coating on the surface of hydrophilic poly(2-hydroxyethyl methacrylate-co-methyl methacrylate ... [more ▼]

Plasma enhanced chemical vapor deposition has been tested for the formation of hydrophobic perfluorinated coating on the surface of hydrophilic poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) [poly(HEMA-co-MMA)] substrates, used for the fabrication of intraocular lenses (IOLs). The properties of the dry and hydrated surface modified by two plasma techniques, Radio-frequency (RF) and Microwave (MW), were investigated in parallel by contact angle measurements in the dry and hydrated state, X-ray photoelectron spectroscopy, and atomic force microscopy. The coating stability and hydrophobicity were challenged by swelling and sterilizing the samples in water. Investigation of the optical performances of the modified samples was performed by ultraviolet spectroscopy and diopter measurements. Since materials with biomedical application are considered, the performances of their surface in contact with lens epithelial cells were tested at in vitro conditions, and repulsion was not found to be enhanced upon modification. Generally, the results showed poor stability of the coating and bring in question its covalent grafting to the surface. [less ▲]

Foams of polycaprolactone/MWNT nanocomposites for efficient EMI shielding

Conference (2008, September 09)

Toward protein and cell repellent properties by surface modification of intraocular lenses

Poster (2008, June 23)

Polymer composite material structures comprising carbon based conductive loads

Patent (2008)

The present invention provides a polymer composite material structure comprising at least one layer of a foamed polymer composite material comprising a foamed polymer matrix and 0.1 to 6 wt% carbon based ... [more ▼]

The present invention provides a polymer composite material structure comprising at least one layer of a foamed polymer composite material comprising a foamed polymer matrix and 0.1 to 6 wt% carbon based conductive loads, such as e.g. carbon nanotubes, dispersed in the foamed polymer matrix. The polymer composite material structure according to embodiments of the present invention shows good shielding and absorbing properties notwithstanding the low amount of carbon based conductive loads. The present invention furthermore provides a method for forming a polymer composite material structure comprising carbon based conductive loads. [less ▲]

Polyolefin matrixes with permanent antibacterial activity: preparation, antibacterial activity, and action mode of the active species

Poster (2008, May 22)

Foams of polycaprolactone/MWNT nanocomposites for efficient EMI reduction

in Journal of Materials Chemistry (2008), 18(7), 792-796

Nanocomposites of polycaprolactone (PCL) filled with multi-walled carbon nanotubes (MWNTs) were foamed by supercritical CO2 in order to prepare materials with reduced electromagnetic interference (EMI ... [more ▼]

Nanocomposites of polycaprolactone (PCL) filled with multi-walled carbon nanotubes (MWNTs) were foamed by supercritical CO2 in order to prepare materials with reduced electromagnetic interference (EMI). Two mixing techniques were used, i.e., melt blending and co-precipitation. Shielding efficiency as high as 60 to 80 dB together with a low reflectivity was observed at a very low vol% of MWNTs (0.25 vol%). The reflectivity of the nanocomposites was advantageously decreased upon foaming. The uniformity of the open-cell structure was assessed by scanning electron microscopy. These foamed PCL/MWNT nanocomposites are very promising EMI shielding materials because their performances result from absorption at low filler content and not from reflection at relatively high filler content as was previously the case. [less ▲]

Improved performances of intraocular lenses by poly(ethylene glycol) chemical coatings

in Biomacromolecules (2007), 8(8), 2379-2387

Cataract surgery is a routine ophthalmologic intervention resulting in replacement of the opacified natural lens by a polymeric intraocular lens (IOL). A main postoperative complication, as a result of ... [more ▼]

Cataract surgery is a routine ophthalmologic intervention resulting in replacement of the opacified natural lens by a polymeric intraocular lens (IOL). A main postoperative complication, as a result of protein adsorption and lens epithelial cell (LEC) adhesion, growth, and proliferation, is the secondary cataract, referred to as posterior capsular opacification (PCO). To avoid PCO formation, a poly(ethylene glycol) (PEG) chemical coating was created on the surface of hydrogel IOLs. Attenuated total reflectance Fourier transform infrared spectroscopy, “captive bubble” and “water droplet” contact angle measurements, and atomic force microscopy analyses proved the covalent grafting of the PEG chains on the IOL surface while keeping unchanged the optical properties of the initial material. A strong decrease of protein adsorption and cell adhesion depending on the molar mass of the grafted PEG (1100, 2000, and 5000 g/mol) was observed by performing the relevant in vitro tests with green fluorescent protein and LECs, respectively. Thus, the study provides a facile method for developing materials with nonfouling properties, particularly IOLs. [less ▲]