340 JOURNAL OF COSMETIC SCIENCE properties. This range suggests that one of these collagens could probably be selected to meet specific manufacturing needs. The tests that have been described allow the poten­ tial collagens to be evaluated, and different batches to be compared for quality assurance. The tests that should be applied to samples will depend on the needs of the particular formulation being developed. A key property of collagens, their water-binding capacity, may also be measured, but this data needs to be treated with care, as the salt present in certain preparations can lead to false interpretations. Of the collagens examined, Atelo­ Helogen® was monomeric and particularly pure, both biochemically and in the absence of salts. The country of origin may be a consideration at present due to risk of any viral or prion-based contamination. Thus, non-bovine collagens may also be preferred as there may be less risk of disease transmission. In this respect, the chicken collagen, Atelo­ Helogen®, is intrinsically more stable than marine collagens. Consumer sensitivity to avian collagens is potentially low, and comparable to mammalian collagens despite the structural differences (data not shown). It has also been suggested that collagen could permeate intact skin and augment the collagenous tissue. This seems implausible, however, as collagen molecules would be too large and too well bound to penetrate the stratum corneum (32). Should collagen or fragments pass into the underlying tissue, they would be unable to participate in the complex biosynthetic pathway that charac­ terizes collagen deposition in tissue (7). Evidence has been presented that confirms that this augmentation does not occur in skin with intact stratum corneum (33). Indeed, the lack of skin penetration should minimize sensitivity issues. ACKNOWLEDGMENTS We thank N. Bartone for assistance with amino acid analysis, G. Heath for assistance with IR spectroscopy, S. McCarthy for assistance with DSC, and Dr J. Ward for assis­ tance with scanning electron microscopy. We thank our suppliers for the gifts of collagen preparations. REFERENCES (1) P. Morganti, S. D. Randazzo, and A. Cardillo, Role of insoluble and soluble collagen as skin mois­ turizer,]. Appl. Cosmetol., 4, 141-152 (1986). (2) J. A. M. Ramshaw, Collagen, Cosmet. Aerosols Toiletr., 1, 22-25 (1986). (3) J. Bella, B. Brodsky, and H. M. Berman, Hydration structure of a collagen peptide, Structure, 3, 893-906 (1995). (4) R. D. B. Fraser, T. P. MacRae, and E. Suzuki, Chain conformation in the collagen molecule,]. Mol. Biol., 129, 463--481 (1979). (5) J. Bella, M. Eaton, B. Brodsky, and H. M. Berman, Crystal and molecular structure of a collagen-like peptide at 1.9 A resolution, Science, 266, 75-81 (1994). (6) R. A. Berg and D. J. Prockop, The thermal transition of a non-hydroxylated form of collagen. Evidence for a role for hydroxyproline in stabilizing the triple-helix of collagen, Biochem. Biophys. Res. Commun., 52, 115-120 (1973). (7) J. F. Bateman, S. Lamande, and J. A. M. Ramshaw, "Collagen Superfamily," in Extracellular Matrix: Vol. 2. Molecular Components and Interactions, W. D. Camper, Ed. (Harwood Academic Publishers, Amsterdam, 1995), pp. 22-67. (8) B. J. Rigby and M. S. Robinson, Thermal transitions in collagen and the preferred temperature range of animals, Nature, 253, 27-279 (1975).

COLLAGEN EVALUATION 341 (9) Standard Methods for the Examination of Water and Wastewater (American Public Health Association, American Water Works Association and Water Environment Federation, Washington, D.C., 1995). (10) E. J. Miller and R. K. Rhodes, Preparation and characterization of the different types of collagen, Meth. Enzymol., 82, 33-64 (1982). (11) R. L. Trelstad, V. M. Catanese, and D. F. Rubin, Collagen fractionation: Separation of native types I, II and III by differential precipitation, Anal. Biochem., 71, 114-118 (1976). (12) U. K. Laemmli, Cleavage of structural proteins during the assembly of the head of bacteriophage T4, Nature, 227, 680-685 (1970). (13) B. Sykes, B. Puddle, M. Francis, and R. Smith, The estimation of two collagens from human dermis by interrupted gel electrophoresis, Biochem. Biophys. Res. Commun., 72, 1472-1480 (1976). (14) J. A. M. Ramshaw and J. A. Werkmeister, Electrophoresis and electroblotting of native collagens, Anal. Biochem., 168, 82-87 (1988). (15) T. Mclellan, Electrophoresis buffers for polyacrylamide gels at various pH, Anal. Biochem, 126, 94-99 (1982). (16) A.G. Gornall, C. J. Bordawill, and M. M. David, Determination of serum proteins by means of the biuret re�ction,J. Biol. Chem., 177, 751-766 (1949). (1 7) K. Kadlec, Extracellular matrix. 1. Fibril-forming collagens, Protein Profile, 5, 519-638 (1994). (18) G. Huszar, J. Maiocco, and F. Naftolin, Monitoring of collagen and collagen fragments in chroma­ tography of protein mixtures, Anal. Biochem., 105, 424-429 (1980). (19) K. J. Payne and A. Veis, Fourier transform IR spectroscopy of collagen and gelatin solutions: Decon­ volution of the amide I band for conformational studies, Biopolymers, 27, 1749-1760 (1988). (20) M. Nagelschmidt and B. Viell, Polarimetric assay for the determination of the native collagen content of soluble collagen,]. Biomed. Mater. Res., 21, 201-209 (1987). (21) T. Hyashi, S. Curran-Patel, and D. J. Prockop, Thermal stability of the triple helix of type I procol­ lagen and collagen: Precautions for minimizing ultraviolet damage to proteins during circular dichro­ ism studies, Biochemistry, 18, 4182-4187 (1979). (22) J. A. M. Ramshaw, Distribution of type III collagen in bovine skin of various ages, Connective Tissue Res., 14, 307-314 (1986). (23) R. A. Condell, V. P. Hanko, E. A. Larenas, G. Wallace, and K. A. McCullough, Analysis of native collagen monomers and oligomers by size-exclusion high-performance liquid chromatography and its application, Anal. Biochem., 212, 436-445 (1993). (24) J. E. Eastoe and A. A. Leach, "Chemical Composition of Gelatin," in The Science and Technology of Gelatin, A.G. Ward and A. Courts, Eds. (Academic Press, London, 1977), pp. 73-107. (25) C. C. Danielsen, Precision method to determine denaturation temperature of collagen using ultraviolet difference spectroscopy, Coll. Relat. Res., 2, 143-150 (1982). (26) P. Bruckner, and D. J. Prockop, Proteolytic enzymes as probes for the triple-helical conformation of procollagen, Anal. Biochem., 110, 360-368 (1981). (27) W. Friess and G. Lee, Basic thermoanalytical studies of insoluble collagen matrices, Biomaterials, 17, 2289-2294 (1996). (28) D. G. Wallace, R. A. Condell, J. W. Donovan, A. Paivinen, W. M. Rhee, and S. B. Wade, Multiple denaturational transitions in fibrillar collagen, Biopolymers, 25, 1875-1895 (1986). (29) J. A. M. Ramshaw, J. A. Werkmeister, and H. A. Bremner, Characterization of type I collagen from the skin of blue grenadier (Macruronus novaezelandiae), Arch. Biochem. Biophys., 267, 497-202 ( 1988). (30) H. C. Wang, J. D. Chen, G. C. Li, and F. H. Yew, Characterization of a heat-resistant strain of Tilapia ovary cells,]. Cell Sci., 92, 353-359 (1989). (31) N. K. Shah, M. Sharma, A. Kirkpatrick, J. A. M. Ramshaw, and B. Brodsky, Gly-Gly-containing triplets of low stability adjacent to a type III collagen epitope, Biochemistry, 36, 5878-5883 (1997). (32) M. Chvapil, Collagen in cosmetics: Misconception of its mode of action, Cosmet. Toiletr., 97, 35-36 (1982). (33) S. D. Coapman, J. L. Lichtin, A. Sakr, and J. R. Schiltz, Studies of the penetration of native collagen, collagen alpha chains, and collagen cyanogen bromide peptides through hairless mouse skin in vitro, J. Soc. Cosmet. Chem., 39, 275-281 (1988).