The Library

Non-destructive mechanical characterisation of UVA/riboflavin crosslinked collagen hydrogels

Tools

Ahearne, Mark, Yang, Y. (Ying), Then, K. Y. and Liu, Kuo-Kang. (2008) Non-destructive mechanical characterisation of UVA/riboflavin crosslinked collagen hydrogels. British Journal of Ophthalmology, Vol.92 (No.2). pp. 268-271. ISSN 0007-1161

Preview

PDF
WRAP_Liu_Br_J_Ophthalmol-2008-Ahearne-268-71.pdf - Published Version - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Download (281Kb)

Official URL: http://dx.doi.org/10.1136/bjo.2007.130104

Abstract

Aims: To establish a non-destructive method of characterising the mechanical properties of collagen hydrogels to model corneal tissue and to examine the effect of photochemical crosslinking on their mechanical properties.

Methods: Collagen hydrogels were manufactured, submerged in 0.1% riboflavin solution and crosslinked using two UVA tube bulbs with an intensity of between 2.8 and 3.2 mW/cm2. The hydrogels were clamped around their outer edge and deformed using a sphere. The deformation was measured in situ using a long-working-distance microscope connected to a CCD camera, and the deformation displacement was used with a theoretical model to calculate the Young modulus of the hydrogels. Collagen hydrogels seeded with human corneal fibroblasts were used to examine cell viability after UVA irradiation.

Results: There was an increase in Young modulus of the collagen hydrogels after UVA/riboflavin treatment that was dependent on the exposure time. UVA irradiation without riboflavin showed decreased mechanical integrity and strength. Cell viability was reduced with increased UVA exposure time.

Conclusion: The non-destructive technique demonstrated a new methodology comparable with strip extensiometry for cornea or corneal model specimens but with more convenient features. This approach could be used as an initial step in developing new crosslinking treatments for patients with keratoconus.

Item Type:

Journal Article

Subjects:

R Medicine > RE Ophthalmology
T Technology > TP Chemical technology

Divisions:

Faculty of Science > Engineering

Library of Congress Subject Headings (LCSH):

Colloids -- Nondestructive testing, Biomechanics, Photochemistry, Keratoconus -- Research, Crosslinking (Polymerization)

Journal or Publication Title:

British Journal of Ophthalmology

Publisher:

BMJ Group

ISSN:

0007-1161

Official Date:

February 2008

Dates:

Date	Event
February 2008	Published

Volume:

Vol.92

Number:

No.2

Number of Pages:

Page Range:

pp. 268-271

Identification Number:

10.1136/bjo.2007.130104

Status:

Peer Reviewed

Publication Status:

Published

Access rights to Published version:

Restricted or Subscription Access

Funder:

North Staffordshire Research and Development Consortium (NSRDC)

References:

1. Spoerl E, Huhle M, Seiler T. Induction of cross-links in corneal tissue. Exp Eye Res
1998;66:97–103.
2. Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-A-induced collagen
crosslinking for the treatment of keratoconus. Am J Ophthalmol 2003;135:620–7.
3. Wollensak G, Spoerl E, Seiler T. Stress-strain measurements of human and porcine
corneas after riboflavin-ultraviolet-A-induced cross-linking. J Cataract Refract Surg
2003;29:1780–5.
4. Maurice DM. Mechanics of the cornea. In: Cavanagh HD, ed, The cornea:
Transactions of the World Congress on the Cornea III. New York: Raven 1988:187–93.
5. Ahearne M, Yang Y, Then KY, et al. An indentation technique to characterize the
mechanical and viscoelastic properties of human and porcine cornea. Ann Biomed
Eng 2007;35:1608–16.
6. Ahearne M, Yang Y, El Haj AJ, et al. Characterizing the viscoelastic properties of thin
hydrogel-based constructs for tissue engineering applications. J R Soc Interf
2005;2:455–63.
7. Minami Y, Sugihara H, Oono S. Reconstruction of cornea in three-dimensional
collagen gel matrix culture. Invest Ophthalmol Vis Sci 1993;34:2316–24.
8. Orwin EJ, Hubel A. In vitro culture characteristics of corneal epithelial, endothelial
and keratocyte cells in a native collagen matrix. Tissue Eng 2000;6:307–19.
9. Reichl S, Bednarz J, Muller-Goymann CC. Human corneal equivalent as cell culture
model for in vitro drug permeation studies. Br J Ophthalmol 2004;88:560–5.
10. Liu KK, Ju BF. A novel technique for mechanical characterization of thin elastomeric
membrane. J Phys D Appl Phys 2001;34:L91–4.
11. Yang WH, Hsu KH. Indentation of a circular membrane. J Appl Mech 1971;38:227–
30.
12. Anseth KS, Bowman CN, Brannon-Peppas L. Mechanical properties of hydrogels and
their experimental determination. Biomaterials 1996;17:1647–57.
13. Begley M, Mackin TJ. Spherical indentation of freestanding circular thin films in the
membrane regime. J Mech Phys Solids 2004;52:2005–23.
14. Wan KT. Fracture mechanics of a shaft-loaded blister test—transition from a
bending plate to a stretching membrane. J Adhesion 1999;70:209–19.
15. Menter JM, Patta AM, Sayre RM, et al. Effect of UV irradiation on type I collagen
fibril formation in neutral collagen solutions. Photodermatol Photoimmunol Photomed
2001;17:114–20.
16. Wollensak G, Spoerl E, Reber F, et al. Keratocyte cytotoxicity of riboflavin/UVAtreatment
in vitro. Eye 2004;18:718–22.
17. Wollensak G, Spoerl E, Wilsch M, et al. Keratocyte apoptosis after corneal collagen
cross-linking using riboflavin/UVA treatment. Cornea 2004;23:43–9.
18. Lundberg B, Jonsson M, Behndig A. Postoperative corneal swelling correlates
strongly to corneal endothelial cell loss after phacoemulsification cataract surgery.
Am J Ophthalmol 2005;139:1035–41.
19. Ozturk E, Ergun MA, Ozturk Z, et al. Chitosan-coated alginate membranes for
cultivation of limbal epithelial cells to use in the restoration of damaged corneal
surfaces. Int J Artif Organs 2006;29:228–38.