Abstract
Raman spectroscopy was applied to investigate changes in the hydration state of chemically modified porcine pericardium tissue. Chemically modified tissues are used in construction of bioprostheses for replacement surgery including dermis, heart valves and blood vessels. The hydration state is a very important factor influencing specific mechanical and immunogenic properties of tissue derived materials. We analysed OH vibrational bands in the Raman spectra measured in the range 3000โ3800 cm^โ1^ for native and glutaraldehyde (GA) crossโlinked porcine pericardium tissue. For deuterated samples Raman spectra were measured in the broadened wavenumber range 2100โ3800 cm^โ1^. All spectra were deconvoluted using the minimum required threeโGaussian fit. Peak position, integrated intensity, separation between two main peaks d~1โ2~, integrated Gaussian OH component intensity ratio K = I~1~/I~2~ and the integrated intensity fraction R = I/I~total~ were determined to analyse changes in Raman OH and OD bands of the collagenous pericardium tissue upon GA treatment. It was found that the formation of collagenโGA crossโlinks causes an increase in the total water content of the tissue and an increase in the interaxial distance between collagen triple helices and introduces changes in the hydration shell surrounding the triple helix. Changes in the hydration shell are postulated to consist mainly of more sufficient formation of hexagonal than pentagonal water clusters in the space between two neighbouring triple helices. The OD and OH Raman bands measured for deuterated tissues revealed the changes in the distribution of water molecules in different subunits of collagen fibrils in the crossโlinked pericardium tissue. Copyright ยฉ 2003 John Wiley & Sons, Ltd.