title: The structural and optical properties of type III human collagen biosynthetic corneal substitutes.
abstract: The structural and optical properties of clinically biocompatible, cell-free hydrogels comprised of synthetically cross-linked and moulded recombinant human collagen type III (RHCIII) with and without the incorporation of 2-methacryloyloxyethyl phosphorylcholine (MPC) were assessed using transmission electron microscopy (TEM), X-ray scattering, spectroscopy and refractometry. These findings were examined alongside similarly obtained data from 21 human donor corneas. TEM demonstrated the presence of loosely bundled aggregates of fine collagen filaments within both RHCIII and RHCIII-MPC implants, which X-ray scattering showed to lack D-banding and be preferentially aligned in a uniaxial orientation throughout. This arrangement differs from the predominantly biaxial alignment of collagen fibrils that exists in the human cornea. By virtue of their high water content (90%), very fine collagen filaments (2-9 nm) and lack of cells, the collagen hydrogels were found to transmit almost all incident light in the visible spectrum. They also transmitted a large proportion of UV light compared to the cornea which acts as an effective UV filter. Patients implanted with these hydrogels should be cautious about UV exposure prior to regrowth of the epithelium and in-growth of corneal cells into the implants.
authors.affiliation: Structural Biophysics Group, Cardiff Centre for Vision Science, Cardiff University, Wales CF24 4HQ, UK; Cardiff Institute for Tissue Engineering and Repair (CITER), Cardiff University, Wales CF24 4HQ, UK.
authors.forename: Sally
authors.initials: S
authors.lastname: Hayes
authors.affiliation: Structural Biophysics Group, Cardiff Centre for Vision Science, Cardiff University, Wales CF24 4HQ, UK; Cardiff Institute for Tissue Engineering and Repair (CITER), Cardiff University, Wales CF24 4HQ, UK.
authors.forename: Phillip
authors.initials: P
authors.lastname: Lewis
authors.affiliation: Swedish Medical Nanoscience Center, Dept. of Neurosciences, Karolinska Institutet, S-17177 Stockholm, Sweden; Integrative Regenerative Medicine Centre, Dept. of Clinical and Experimental Medicine, Cell Biology Bldg. - Level 10, Linköping University, S-58185 Linköping, Sweden.
authors.forename: M Mirazul
authors.initials: MM
authors.lastname: Islam
authors.affiliation: Diamond Light Source, Didcot, Oxfordshire OX11 ODE, UK.
authors.forename: James
authors.initials: J
authors.lastname: Doutch
authors.affiliation: Diamond Light Source, Didcot, Oxfordshire OX11 ODE, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Sorensen
authors.affiliation: Structural Biophysics Group, Cardiff Centre for Vision Science, Cardiff University, Wales CF24 4HQ, UK; Cardiff Institute for Tissue Engineering and Repair (CITER), Cardiff University, Wales CF24 4HQ, UK.
authors.forename: Tomas
authors.initials: T
authors.lastname: White
authors.affiliation: Swedish Medical Nanoscience Center, Dept. of Neurosciences, Karolinska Institutet, S-17177 Stockholm, Sweden; Integrative Regenerative Medicine Centre, Dept. of Clinical and Experimental Medicine, Cell Biology Bldg. - Level 10, Linköping University, S-58185 Linköping, Sweden.
authors.forename: May
authors.initials: M
authors.lastname: Griffith
authors.affiliation: Structural Biophysics Group, Cardiff Centre for Vision Science, Cardiff University, Wales CF24 4HQ, UK; Cardiff Institute for Tissue Engineering and Repair (CITER), Cardiff University, Wales CF24 4HQ, UK. Electronic address: MeekKM@cardiff.ac.uk.
authors.forename: Keith M
authors.initials: KM
authors.lastname: Meek
mesh_terms: D024061:Collagen Type III / Q000737:chemistry* / Q000648:ultrastructure; D003315:Cornea / Q000737:chemistry* / Q000648:ultrastructure; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry; D008689:Methacrylates / Q000737:chemistry; D055620:Optical Phenomena; D010767:Phosphorylcholine / Q000031:analogs & derivatives / Q000737:chemistry; D019736:Prostheses and Implants; D012031:Refractometry; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D024061:Collagen Type III; D008689:Methacrylates; D010767:Phosphorylcholine; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; C070638:2-methacryloyloxyethyl phosphorylcholine
keywords: Collagen; Cornea; Recombinant protein; Transplantation