Double-network-based composite hydrogel as a synthetic OOKP skirt

A keratoprosthesis (KPro), or artificial cornea, is used as a corneal substitute, where a conventional corneal transplantation is not viable. The Boston type-1 KPro and osteo-odonto-keratoprosthesis (OOKP) are two devices proven successful so far. The Boston KPro is suitable for the wet blinking eyes and the latter for a dry and keratinised ocular surface with a poor blink mechanism.

The OOKP is usually made from the patient’s own tooth and its surrounding jaw bone. This creates significant oral damage and consumes considerable operating time and resources. Furthermore, some patients do not have any suitable tooth. Allografting from a living related donor and tibial bone are alternatives in practice, but they do not provide enough longevity of the device. Therefore, there is a need to replace the dental lamina with an analogue.

Project timeframes

The project began in 2013 and is ongoing.

Project aims

The aim of this project is to study the clinical and radiological features of OOKP laminar resorption and to develop a novel, synthetic, bi-layer polymeric OOKP lamina substitute.

A synthetic OOKP lamina should mimic the positive aspects of the current dentin-bone bilayer design whilst overcoming the negatives. The bilayer mimic should be mechanically strong, erosion resistant and maintain bond strength with the central PMMA optic and surrounding tissue over time. The lower dentin mimicking layer should provide a relatively non-porous tissue seal to prevent cell overgrowth and potential for infection posteriorly to the implant. The upper layer should be porous for cell in-growth with a high mineral content for cell deposition of tissue allowing the implant to be sutured in place and anchored over time.

Project findings and impact

A biomineralised cellular composite interpenetrating network hydrogel scaffold has been synthesised as a potential candidate for the upper layer of the bilayer OOKP lamina. An optimised hydrogel composite was developed and shown to have improved mechanical properties and to support viable cell growth which could be controlled by the introduction of hydroxyapatite coated PLGA microspheres.

Such materials, once fully developed may be used as synthetic dental lamina analogues in OOKP surgery.

Research team

Dr Venkata Avadhanam

Dr Ganesh Ingavle

Dr Susan Sandeman

Professor Andrew Lloyd

Chris Liu

Output

G Ingavle, S Sandeman.Invited speaker presentation 5th EU Cornea Congress, Excel London, London, UK. (9-14). ‘A synthetic OOK analogue’

V Avadhanam, G Ingavle, C Liu, S Sandeman. Joint best paper in the Keratoprosthesis Free Paper Session at 6th EuCornea Congress, Barcelona, Spain (9-2015) ‘An engineered hydrogel-based double network composite for synthetic osteo-odonto-keratoprosthesis skirt’

Ganesh Ingavle, Venkata Avadhanam, Yishan Zheng, Christopher Liu, Susan Sandeman. An Engineered Double-Network-Based Composite Hydrogel for a Synthetic OOKP Skirt. Poster presentation. 27th European Conference on Biomaterials 20th August-3rd September 2015. Krakow, Poland.

G Ingavle, V Avadhanam, Y Zheng, C Liu, S Sandeman (2016). Biomineralized interpenetrating network hydrogels for bone tissue engineering. Bioinspired, Biomimetic and Nanobiomaterials. Published online 8th Jan 2016. DOI: 10.1680/jbibn.15.00013

Partners

Mr Chris Liu, Consultant Ophthalmologist, Sussex Eye Hospital, Brighton, East Sussex, UK