Hydrogel based keratoprosthesis

Keratoprosthesis (KPs) are made from biomaterials which can differ significantly in their physical, chemical and biological properties. There are hydrophobic matteials as well as hydrophilic materials, each material has a limited spectra of use. An complex implantant, such as a KPs needs different surfaces to be integrated stable and for a long term without causing side reactions such as inflammation or rejection. This, there a different pre requirements to be fullfilled in order to create a long tetm stable KP. Articial hydrogels differ in many kinds from the natural hydrogel, the collagen, of the cornea.In this presentation, the fundamental mechanisms of understanding hydrogels and there limits of use as well the modification of artifical hydrogels to adopt the requirements to be be used for long-term stable KP are discussed. Furthermore it will be shown, how the perfomrkance of a KP can be predicted in vivo and the results can be used to use this expermental results and translate them into clinical application. Different kinds of KPs based an hydgrogel materials, native based and artifical materials, their limits, use andtheir performanance will be presented in order to contribute to the medical advances in corneal science

Nanotechnology in cosmetics - the key to better performance?

Nanotechnology is an area with auspicious prospects for turning fundamental research into successful innovations. Its application in cosmetics can offer a lot of advantages. Nanotechnology brings new tools, enabling making products with improved property profile. Typical examples are related to hair-, skin- and eye care. Waterborne polymer systems as well as inorganic particles play an important role in cosmetics and the range of functions is from stabilising to protection, from compatibiliser to nano-carriers of active ingredients to skin and hair, not to forget the decorative and aesthetic effects which are desired

The fully synthetic, bio-coated MIRO® CORNEA UR keratoprosthesis: Development, preclinical testing, and first clinical results

Grundlagen Die MIRO® CORNEA UR Keratoprothese wird aus einem einzigen Stück flexiblen, hydrophoben Acrylatpolymers gefertigt. Die Geometrie lehnt sich an das ursprüngliche Cardona-Design an, das sowohl die epicorneale als auch die intrastromale Implantation erlaubt. Die Beschichtung der Haptik mit gentechnisch hergestelltem Fibronektin unterstützt das Einwachsen in das umgebende Gewebe. Die Flexibilität der Haptik minimiert die Scherkräfte zwischen der Keratoprothese und dem Augengewebe und erleichtert die Überwachung des intraokularen Drucks in einem Patientengut mit häufig auftretendem Glaukom. Material und Methodik Die MIRO® CORNEA UR wurde in jeweils ein Auge von vier hornhautblinden Patienten mit Autoimmunerkrankung oder schweren Verbrennungen und Verätzungen implantiert. Die Haptik wurde in eine Tasche zwischen Auge und zuvor transplantierter autologer Mundschleimhaut positioniert und mit einer Manschette aus Spendersclera oder einer Kollagenmembran zusätzlich gesichert. Resultate In drei der vier Augen verwuchs das umgebende Gewebe fest mit der Haptik und durchdrang deren Löcher. Während der gesamten Nachbeobachtungszeit von 20 bis 52 Monaten waren die Haptiken fest in das umgebende Gewebe integriert ohne Anzeichen einer Entzündung. Postoperativ wurden die Augen mit Antibiotika und Cortison Augentropfen behandelt. Sie blieben stabil, mit gutem Tonus und frei von Infektionen. Weder Einschmelzen von Gewebe, noch Einwachsen von Epithelzellen an der Grenze zwischen Keratoprothese und umgebendem Gewebe wurden beobachtet. Schlussfolgerungen Die MIRO® CORNEA UR Keratoprothese könnte eine Alternative sein zur Osteo-Odonto-Keratoprothese (OOKP) zur Behandlung hornhautblinder Patienten mit Autoimmunerkrankung oder schweren Verbrennungen oder Verätzungen. In der Zukunft könnten die Indikationen tiefe Hornhautvaskularisationen einschließen, wie sie nach schweren Augeninfektionen auftreten

Analyse von explantierten eingetrübten Intraokularlinsen

J. W. Adcroft's Waltzer - A74 - photographed May 2003

New chain transfer agents for reversible addition-fragmentation chain transfer (RAFT) polymerisation in aqueous solution

New chain transfer agents for free radical polymerisation via reversible addition-fragmentation chain transfer (RAFT) were synthesised that are particularly suited for aqueous solution polymerisation. The new compounds bear dithioester and trithiocarbonate moieties as well as permanently ionic groups to confer solubility in water. Their stability against hydrolysis was studied, and compared with the one of a frequently employed water-soluble RAFT agent, using UV-Vis-spectroscopy and H-1-NMR measurements. An improved resistance to hydrolysis was found for the new RAFT agents compared to the reference one, providing good stabilities in the pH range between 1 and 8, and up to temperatures of 70 degreesC. (C) 2004 Elsevier Ltd. All rights reserved

Biomaterials in ophthalmic applications - IOL´s and keratoprosthesis

Biomaterials can be regarded as synthetic or non-living native materials used in therapeutic approaches. This direct contact with body tissue manifests itself in a wide spectrum of chemical, physical and biochemical interactions. In ophthalmology, biomaterials find their application in the development of intraocular lenses (IOL´s) and keratoprosthesis. The chemical nature of these materials encompasses the full spectrum of physico-chemical properties of matter, e.g. hydrophilic and hydrophobic poly(meth)acrylates, silicones and fluorinated polymers. Concordantly, the intended use and functionality of the implant necessitates the strict selection of the desired chemical and physical characteristics of the materials to be used, if not the de-novo creation of suitable substances. In addition, modification of surfaces or the creation of gradual changes in material properties by co-polymerizations or alternative means of tailoring peculiar aspects of the device may be required to achieve reasonable or functional substitution of the diseased tissue, all the while maintaining ease of the device's usage by the caring physician and, above all, uncompromised patient's safety in the intended use of the device throughout its lifecycle