Collagen fiber structure and organization have been found to vary in different tendon types. Differences have been reported in the FT-IR spectra of the amide I band of collagen-containing structures. In the present study, the FT-IR spectral characteristics of the amide I band of the bovine flexor tendon and the extended rat tail tendon were compared by using the diamond attenuated total reflectance technique. The objective was to associate FT-IR spectral characteristics in tendons with their different collagen fiber supraorganization and biomechanical properties. Nylon 6 and poly-l-lysine were used as polyamide models. Each of these materials was found to exhibit molecular order and crystallinity, as revealed by their birefringence. The following FT-IR parameters were evaluated: amide I band profile, absorption peaks and areas, and the 1655cm -1/1690cm -1 absorbance ratio. The amide I area and the 1655cm -1/1690cm -1 absorbance ratio were significantly higher for the bovine flexor tendon, indicating that its collagen fibers are richer in pyridinoline-type cross-linking, proline and/or hydroxyproline and H-bonding, and that these fibers are more packed and supraorganizationally ordered than those in the rat tail tendon. This conclusion is additionally supported by differences in collagen solubility and biochemical/biomechanical properties of the tendons. © 2010 Elsevier Ltd.423283289Aparicio, S., Doty, S.B., Camacho, N.P., Pachalis, E.P., Spevak, L., Mendelsohn, R., Boskei, A.L., Optimal methods for processing mineralized tissues for Fourier transform infrared microspectroscopy (2002) Calcif. Tissue Int., 70, pp. 422-429Benjamin, M., Kaiser, E., Milz, S., Structure-function relationships: a review (2008) J. Anat., 212, pp. 211-228Bi, X., Li, G., Doty, S.B., Camacho, N.P., A novel method for determination of collagen orientation in cartilage by Fourier transform infrared imaging spectroscopy (FT-IRIS) (2005) Osteoarthr. Cartil., 13, pp. 1050-1058Blank, R.D., Baldini, T.H., Kaufman, M., Bailey, S., Gupta, R., Yershov, Y., Boskey, A.L., Paschalis, E.P., Spectroscopically determined collagen Pyr/deH-DHLNL cross-link ratio and crystallinity indices differ markedly in recombinant congenic mice with divergent calculated bone tissue strength (2003) Connect. Tissue Res., 44, pp. 134-142Boskey, A., Camacho, N.P., FT-IR imaging of native and tissue-engineered bone and cartilage (2007) Biomaterials, 28, pp. 2465-2478Bryan, M.A., Brauner, J.W., Anderie, G., Flach, C.R., Brodsky, B., Mendelsohn, R., FTIR studies of collagen model peptides: complementary experimental and simulation approaches to conformation and unfolding (2007) J. Am. Chem. Soc., 129, pp. 7877-7884Camacho, N.P., West, P., Torzilli, P.A., Mendelsohn, R., FTIR microscopic imaging of collagen and proteoglycan in bovine cartilage (2001) Biopolymers, 62, pp. 1-8Coats, A.M., Hukins, D.W.L., Imrie, C.T., Aspden, R.M., Polarization artefacts of an FTIR microscope and the consequences for intensity measurements on anisotropic materials (2003) J. Microsc., 211, pp. 63-66Fouda, I.M., Evaluation of the form birefringence and other structural parameters due to thermal annealing for nylon 6 fibers (2002) J. Polym. Res.-Taiwan, 9, pp. 37-44Griffiths, P.R., Haseth, J.A., (2007) Fourier Transform Infrared Spectrometry, , Wiley-Interscience, Hoboken, USAHamza, A.A., Fouda, I.M., El-Farahaty, K.A., Seisa, E.A., Optomechanical properties of fibres. 1. Optical anisotropy in stretched nylon-6 fibers (1991) Polymer Test., 10, pp. 83-90Jackson, M., Mantsch, H.H., The use and misuse of FTIR spectroscopy in the determination of protein structure (1995) CRC Crit. Rev. Biochem. Mol. Biol., 30, pp. 95-120Jastrzebska, M., Zalewska-Rejdak, J., Mróz, I., Barwinski, B.I., Wrzalik, R., Kocot, A., Nozynski, J., Atomic force microscopy and FT-IR spectroscopy investigations of human heart valves (2006) Gen. Physiol. Biophys., 25, pp. 231-244Józsa, L.G., Kannus, P., (1997) Human Tendons Anatomy, Physiology, and Pathology, p. 573. , Human Kinetics, Champaign, USAKaminska, A., Sionkowska, A., Effect of UV radiation on the infrared spectra of collagen (1996) Polymer Degrad. Stab., 51, pp. 19-26Ker, R.F., Mechanics of tendon, from an engineering perspective (2007) Int. J. Fatigue, 29, pp. 1001-1009Kjaer, M., Role of the extracellular matrix in adaptation of tendon and skeletal muscle to mechanical loading (2004) Physiol. Rev., 84, pp. 649-698Lazarev, Y.A., Grishkovsky, B.A., Khromova, T.B., Amide I band of IR spectrum and structure of collagen and related polypeptides (1985) Biopolymers, 24, pp. 1449-1478Lee, K.-H., Kim, K.-W., Pesapane, A., Kim, H.-Y., Rabolt, J.F., Polarized FT-IR study of macroscopically oriented electrospun nylon-6 nanofibers (2008) Macromolecules, 41, pp. 1494-1498Liu, K.-Z., Jackson, M., Sowa, M.G., Ju, H., Dixon, I.M.C., Mantsch, H.H., Modification of the extracellular matrix following myocardial infarction monitored by FTIR spectroscopy (1996) Biochim. Biophys. Acta, 1315, pp. 73-77Mello, M.L.S., Vidal, B.C., Experimental tendon repair: glycosaminoglycan arrangement in newly synthesized collagen fibers (2003) Cell Mol. Biol., 49, pp. 579-585Nakagaki, W.R., Pimentel, E.R., Benevides, G.P., Gomes, L., The effect of age and spontaneous exercise on the biochemical and biophysical properties of chicken superficial digital flexor tendon (2010) Connect. Tissue Res., 51, pp. 265-273Payne, K.J., Veis, A., Fourier transform IR spectroscopy of collagen and gelatin solutions: deconvolution of the amide I band for conformational studies (1988) Biopolymers, 27, pp. 1749-1760Sellaro, T.L., Hildebrand, D., Lu, Q.J., Vyavahare, N., Scott, M., Sacks, M.S., Effects of collagen fiber orientation on the response of biologically derived soft tissue biomaterials to cyclic loading (2007) J. Biomed. Mater. Res., 80 A, pp. 194-205Singh, B.R., (2000) Infrared Analysis of Peptides and Proteins: Principles and Applications. Amer. Chem. Soc. Series 750, p. 240. , Oxford Univ. Press, Corby, UKSusi, H., Ard, J.S., Carroll, R.J., The infrared spectrum and water binding of collagen as a function of relative humidity (1971) Biopolymers, 10, pp. 1597-1604Tiong, W.H.C., Damodaran, G., Naik, H., Kelly, J.L., Pandit, A., Enhancing amine terminals in an amine-deprived collagen matrix (2008) Langmuir, 24, pp. 11752-11761Twardowski, J., Anzenbacher, P., (1994) Raman and IR Spectroscopy in Biology and Biochemistry, , Ellis Horwood Ltd., Chichester, UKVidal, B.C., The part played by mucopolysaccharides in the form birefringence of collagen (1965) Protoplasma, 59, pp. 472-479Vidal, B.C., Evaluation of carbohydrate role in the molecular order of collagen bundles. Microphotometric measurements of textural birefringence (1986) Cell Mol. Biol., 32, pp. 527-531Vidal, B.C., Crimp as part of a helical structure (1995) C. R. Acad. Sci. Paris Sci. Vie/Life Sci., 318, pp. 173-178Vidal, B.C., From collagen type I solution to fibers with helical pattern: a self-assembly phenomenon (1995) C. R. Acad. Sci. Paris Sci. Vie/Life Sci., 318, pp. 831-836Vidal, B.C., Image analysis of tendon superstructure using interference and polarized light microscopy (2003) Micron, 34, pp. 423-432Vidal, B.C., Mello, M.L.S., Structural organization of collagen fibers in chordae tendinae as assessed by optical anisotropic properties and fast Fourier transform (2009) J. Struct. Biol., 167, pp. 166-175Vidal, B.C., Mello, M.L.S., Optical anisotropy of collagen fibers of rat calcaneal tendons: an approach to spatially resolved supramolecular organization (2010) Acta Histochem., 112, pp. 53-61Vigano, C., Manciu, L., Buyse, F., Goormaghtigh, E., Ruysschaert, J.-M., Attenuated total reflection IR spectroscopy as a tool to investigate the structure, orientation and tertiary structure changes in peptides and membrane proteins (2000) Biopolymers, 55, pp. 373-380Viidik, A., Nieksen, H.M., Skalicky, M., Influence of physical exercise on aging rats: II. Life-long exercise delays aging of tail tendon collagen (1996) Mech. Age. Devel., 88, pp. 139-148Vilarta, R., Vidal, B.D., Anisotropic and biomechanical properties of tendons modified by exercise and denervation-aggregation and macromolecular order in collagen bundles (1989) Matrix, 9, pp. 55-61Wagnusson, S.P., Hansn, P., Kjaer, M., Tendon properties in relation to muscular activity and physical training (2003) J. Med. Sci. Sports, 13, pp. 211-223