R-hirudin Immobilization And The Property Research Of Acrylic Intraocular Lens

Intraocular lens （IOL） implantation is the main method of treatment of cataract. Itsfunction is to maintain transparency, smooth light from outside passes through pupil, IOL,vitreous and finally reaches the retina. IOL center shall not appear foreign bodies blocking thelight. But if the biological performance of IOL is not good, it’s easy to induce inflammationby foreign body reaction, and the adhesion of protein and cells, causing IOL turbidity, andthat’s called secondary cataract. The purpose of this study is to improve the biologyperformance of IOL surface, focusing on the surface physical and chemical properties and thebiocompatibility, utilizing plasma treatment and protein grafting technology. The innovativepoint of this research was the introduction of r-hirudin onto IOL surface, which can resist theclotting of platelet and adhesion and hyperplasia of cells, significantly improved thebiological behaviors such as the adhesion and hyperplasia of proteins and cells on the surfaceof IOL.In this study, we firstly used ammonia plasma treatment method for the PMMA surface.Ammonia plasma treatment introduce nitrogen groups, ions and free radicals such as NH2、NH³⁺、N C=O etc. onto the surface, providing binding sites to build biological hirudincoating for the later. The optimum treatment parameter for the processing was power80W,pressure25pa, treatment time5min, surface hydrophilicity of PMMA obtained under thiscondition is improved, the contact angle decreased to the minimum platform region; the polarcomponent and the surface energy reached to the maximum plateau region, which made thereaction with outsiders more easily; the hills shaped bulge appeared on the surface, and theroughness increased; N element content increased to the highest, NH3+ion is the mostimportant element of the existing N status.Followed by ammonia plasma-treated PMMA （plasma） we take the measure ofimmersing to introduce hirudin peptides onto the surface. Soaking in500μg/ml hirudinsolutions for4h, the coverage rate reached to the highest, the hill-like protrusions of theoriginal surface become taller and sleeker, the hydrophilicity of surface slightly decreased, thesurface energy increases, and the chemical stability improved. After the introduction of hirudin, S, N elements appeared on the surface, and N element content decreased, of whichN C=O groups content increased.After the hirudin peptides coating successfully formed on the PMMA surface, theirbiological properties such as the resisting of fibronectin adhesion and degeneration, anti-celladhesion, proliferation, and metaplasia were inspected, and the direct observation ofintraocular lens affected by the animal tissues after implanting into the bunny eyes wasconducted. The results showed that, the modified material has significant anti-fibronectinadhesion effect, and the conformational change did not occur; lens epithelial cell adhesion isalso greatly reduced. After the modification, the turbidity of IOL within the rabbit eyesignificantly reduced, while large number of cells adhered on the plasma-treated IOL surface,and with time cells gradually formed proliferation film, which blocked the IOL central visual.Using ammonia plasma treatment method to conduct polypeptide hirudin biologicalconstruction on the PMMA surface improved the surface hydrophilicity and biologicalproperties, the purpose of resistant of fibronectin adhesion and degeneration, the lensepithelial cell adhesion, proliferation, and metaplasia were reached, and the prevention ofoccurrence of turbidity in the rabbit eye were effectively prevented, which meant a lot for theprevention of the occurrence of IOL turbidity, the formation of secondary cataract.