Hydrogel fix for cleft palate
A UK-USA research team has been working to improve the treatment of cleft palates using hydrogels.
Cleft lip and/or palate affects one in 700 children worldwide. Repair involves surgically repositioning the available palatal mucosa to cover the gap. If the defect is large, there may not be enough skin available to close the gap without radical surgery.
The potential new treatment involves inserting a small plate made of anisotropic hydrogel under the mucosa of the roof of the patient’s mouth. This gradually expands as fluid is absorbed, encouraging skin growth. When sufficient skin has grown, the plate is removed and the cleft repaired using the additional tissue.
Professor David Bucknall was one of the University of Oxford, UK, researchers involved in the project. He has since moved to the Georgia Institute of Technology, USA, where he continues to work with the UK team.
He explains that the polymer used is the same as that found in soft contact lenses – a mixture of methyl methacrylate with vinylpyrrolidone. The team has worked with a contact lens manufacturer to reformulate the ratios so the material has the same chemistry but a greater volume of expansion.
Material characterisation included observing the expansion rate as a function of time and using mechanical measurements to obtain cross-link densities. In addition, the Science and Technology Facilities Council’s ISIS Neutron Source, UK, has been used to study what happens to the water as it diffuses into the material and how that affects the structure as it expands.
To obtain anisotropic expansion, annealing compression under heat is applied. ‘The gel then expands in the opposite direction to the compression, “in effect”,’ says Bucknall. ‘It is a type of shape memory [polymer].’
The gel also has potential for other surgeries, including syndactyly (congenitally fused fingers), post-burns, nasal reconstruction and scar revision.
The first clinical trials are planned for early 2011. Ongoing work will concentrate on creating a switch to trigger the device’s expansion, allowing the insertion incision to heal before expansion starts.
Materials World Magazine, 01 May 2010
Cleft lip and/or palate affects one in 700 children worldwide. Repair involves surgically repositioning the available palatal mucosa to cover the gap. If the defect is large, there may not be enough skin available to close the gap without radical surgery.
The potential new treatment involves inserting a small plate made of anisotropic hydrogel under the mucosa of the roof of the patient’s mouth. This gradually expands as fluid is absorbed, encouraging skin growth. When sufficient skin has grown, the plate is removed and the cleft repaired using the additional tissue.
Professor David Bucknall was one of the University of Oxford, UK, researchers involved in the project. He has since moved to the Georgia Institute of Technology, USA, where he continues to work with the UK team.
He explains that the polymer used is the same as that found in soft contact lenses – a mixture of methyl methacrylate with vinylpyrrolidone. The team has worked with a contact lens manufacturer to reformulate the ratios so the material has the same chemistry but a greater volume of expansion.
Material characterisation included observing the expansion rate as a function of time and using mechanical measurements to obtain cross-link densities. In addition, the Science and Technology Facilities Council’s ISIS Neutron Source, UK, has been used to study what happens to the water as it diffuses into the material and how that affects the structure as it expands.
To obtain anisotropic expansion, annealing compression under heat is applied. ‘The gel then expands in the opposite direction to the compression, “in effect”,’ says Bucknall. ‘It is a type of shape memory [polymer].’
The gel also has potential for other surgeries, including syndactyly (congenitally fused fingers), post-burns, nasal reconstruction and scar revision.
The first clinical trials are planned for early 2011. Ongoing work will concentrate on creating a switch to trigger the device’s expansion, allowing the insertion incision to heal before expansion starts.
Materials World Magazine, 01 May 2010
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