Rehabilitation of patients with the eye’s iris defects of congenital (aniridia, iris colobomas, albinism) or post-traumatic nature continues to be one of the most difficult problems of the ophthalmological practice. These problems are not only cosmetic eye defects, but can lead to such clinical manifestations as the appearance of spherical and chromatic aberrations, diplopia, severe photophobia, retinal dystrophy, amblyopia in congenital aniridia and low visual acuity in post-traumatic aniridia. As is known, in some cases, the loss of an organ or tissue can be compensated by transplantation of donor material. But there are cases when transplantation is very limited or, simply, excluded. It is known that some donor organs and tissues cannot be transplanted from one person to another, as an allogeneic transplant;this concerns the iris of the eye. Therefore, the search for ways to eliminate iris defects does not stop. New medical products, materials and surgical procedures, while continuing to improve current healthcare practices, are being used more and more successfully and continue to develop. Many of these innovations involve low-cost and technologically modeled polymer materials that must meet specific clinical and financial requirements.

The first of the main and obligatory factors in this case is sterility, bio immune inertness and biocompatibility between the organism’s native physiological environment and the surface of the synthetic biomaterial.

In order to compensate for iris defects, various methods of artificial diaphragm of the eye are used. Intrastromal implants in the form of blue-stained perforated annular PMMA plates were first used in 1960-1967 by P. Choce to patients with aniridia, albinism and traumatic mydriasis. Dr. H.R. Koch partnered with Human Optics to develop a new type of elastic artificial iris made from GoreTex / Silicone, and reported the results of the implantation at the XXII ESCRS Congress in 2004. These implants are currently manufactured by a subsidiary DR. SCHMIDT. In the early 90s R. Sundmacher together with Morcher GmbH returned to P. Choyce's idea of creating molds for IOL with a black-painted haptic part for implantation into the posterior chamber or into the iridociliary sulcus for aniridia correction.

In Russia, in 2000, the first application of IOL with a stained haptic playing the role of Irido-Lens Diaphragm (ILD) was reported. For the first time, ILDs were developed by the Cheboksary branch together with with the Experimental & Technical production of the, ISTC "Eye Microsurgery" and with the participation of the Moscow State University named after M.V. Lomonosov, its laboratory of advanced technologies.

The proposed ILD construction is a combination of Siloxane and PMMA IOL, which combines elasticity, lightness, noninvasiveness of the polysiloxane haptic part, with the transparency and inertness of PMMA IOL proven for decades. Thus, the optical part of the IOL was made of PMMA, and its haptic part, which performs the function of the iris, was made of polysiloxane. In the trend of nanotechnology, this ILD design was processed by applying a carbyne-containing film to the surface in order to ensure the biocompatibility of the ILD material. However, it is difficult, more precisely - it is impossible to imagine the technology of simultaneous SNM (surface nanomodification) of different polymeric materials with different physicochemical characteristics and properties. It should also be noted that there is great doubt about the feasibility of serial production of IDI at ISTC without comparing statistical data on the number of patients with different parameters of visual functions who require surgical intervention, such as pseudophakia and / or only iridoplasty. Statistical analysis and elementary logic show that such an ILD manufacturing company can only be unprofitable. We should also mention the artificial irises CustomFlex Artificial Iris (ArI) of the German company HumanOptics AG, made of thin and flexible medical silicone

Today, a more refined ArI has been proposed based on a special polymer material, a liquid crystal elastomer which expands under the influence of light and contracts with decreasing light levels - this is a more modern AI model developed by scientists and technologists from Finland and Poland. In Russia, there are the works of scientists from Moscow State University V.P. Shibaev and A.Yu. Bobrovsky on the study of liquid crystal polymers, on the trends of their development and use as photocontrolled materials.

Changing the shape of the material causes the hole, as the imitation of the iris pupilla in the center, to become either larger or smaller, making the ArI work just like the native iris. It can be stated that at the present time flexible silicone, which has perfectly proven itself in the production of IOL, is more often chosen for the manufacture of modern ArI. However, to date, the complications after implantation of prostheses from

However, to date the complications after the implantation of silicone and silicone-containing materials (SCM) prostheses into living tissues have been sufficiently known.

These materials are inevitably degraded in the body; more often this complication is accompanied by implantation of prostheses with a larger (predominant) mass of silicone, such as, for example, breast prostheses, and having a pronounced blood supply to the organ or tissue being replaced. In such cases, the silicone in the prosthesis is more often undergoing degradation, decomposition material accompanied by the release of very toxic silicone oil. In addition to silicone oil, water is released, which is capable of tearing the protective coating films on the surface of the SCM prosthesis Attempts to treat the surface of silicone prostheses for silicon material protecting, just like NMS, often led to malignant processes, as is known from the scientific literature. Therefore, it should not be forgotten that the iris is a part of the powerful choroid of the eye.

The authors of ILD in ISTC "Eye Microsurgery” also soon reported that the carbine coatings were

washed out from the surface of the ILD they had developed, which had already been implanted.

In 2005, we continued our research to expand the possibilities of creating new materials, including materials for an ArI, having already had some experience in obtaining various NSS and NMS of various surfaces of polymer materials in order to obtain certain NCPM (nanocomposite polymer material) for their further expedient use. The results were published in Proceedings of The First International Conference on Biological and Medical Physics, March 2005, Int.J.Sci.Res.Vol16, pp507-512 (2006). This article presents the results of additional research methods: the antimicrobial activity of carbon-containing films, their biocompatibility and toxicology, as well as the results of studies of the adhesive properties of carbon-containing coatings and the results of studies on laboratory animals. The aim of our work was to try to create a material using PVDF NMS, and study the possibility of using derivatives of these materials for the manufacture of an ArI that does not contain silicone. The correct solution to the problem of creating an eye diaphragm can only be found by developing artificial substitutes as close to the required properties of ArI materials as possible. Application of a modified carbon-containing MCCF films such as: diamond-like, carbyne, carbyne-containing carbon films and nanotubes, by deposition on a pre-nanostructured surface (NSS) to obtain new materials with specified physicochemical properties of the surface, ensuring the biocompatibility of the material, and having the bioactive properties of the surfaces of synthetic materials, is being widely developed. The main characteristics of materials and derivatives in the nanoscale range are determined not only by a decrease in the size of the structural elements, but also by the appearance of the quantum-size effects, the wave nature of transient processes, and the dominant role of the interfaces. By changing the size and shape of nanostructures, it is possible to obtain new functional characteristics of the materials that differ significantly, and sometimes unexpectedly, from the properties of the bulk materials. The selection of polymer initial materials such as PET, PTFE and PVDF has allowed the wide range of applications of these polymers in biology and medicine to be explored, as well as the possibility of providing a large number of promising properties of NCPM after NMS of these polymers.

In our work, PVDF was used, which favorably differs from other polymers, with the following properties:

• Wide range of operating temperatures;
• High thermal stability;
• High chemical resistance, including at elevated temperatures;
• Resistance to ultraviolet and gamma radiation;
• Material purity and absence of technological impurities;
• The presence of piezo and pyroelectric properties.

Nanomodification of the polymer surface using nanotechnology is aimed at modifying the physical and chemical characteristics of the surface: relief, chemical composition of elements, atomic structure, and charge on the surface, providing inertness, which can promote adhesion properties or, on the contrary, to impart repulsive properties of certain elements, biochemical compounds, proteins, cells from the interface.

NSS and NMS PVDF were performed according to the previously mentioned technologies, which is achieved by the NSS of the polymer surface by means of its treatment with streams of ions of reactive or inert gases, or their mixture, followed by NMS of the formed nanorelief, application of a nano-sized film coating including carbon, using ion-stimulated deposition in vacuum. By adjusting the parameters of the NSS relief by changing the composition of the gas for treatment with ion flows, and / or the material for further deposition of the carbon film, and / or choosing the mode for these operations with the possibility of obtaining NMS under different technological modes, new specified properties of the material surface were determined.

One of the most attractive aspects of the NMS technology is the ability to simultaneously nanomodify the polymer surface, guarantee its sterility, and exclude the development of fibrous tissue on it after implantation. Thus, the obtained materials possessed certain specified properties: physicochemical stability of NMS, hydrophobicity, sterility of the surface obtained, which was determined by the listed surface properties, which should have allowed such NMPMs to be considered as materials for the manufacture of iris prostheses. The essential properties of the material for an artificial iris are the absence of toxicity, its inertness, biocompatibility and dispersion of the surface, the presence of a certain adhesive or repulsive effect on cells and elements, which is achieved by NMS. The new specified physicochemical properties of NCPM could allow their successful application as a material for the manufacture of an artificial iris substitute with the prospect of further expanding the use of NCPM in ophthalmological practice, medicine and biology.

ArI Artificial Iris

PMMA polymetilmethacrylate

PET polyethyleneterephtalate

PTFE polytetrafluorethylene

PVDF polyvinylidene fluoride

IOL Intraocular lens

ILD Iris-Lens Diaphragm

NSS Surface Nano Structuring; Surface Nano Structured

NMS Nano Modified Surface

CPM Nano Composite Polymer Material

МСCF Modifying Carbon Containing Film

SNM Surface Nano Modification

SCM Silicon Containing Material

ISTC (Inter-branch Scientific and Technical Complex)