JOURNAL OF COSMETIC SCIENCE 240 produces trehalose glasses in situ at their current locations. The trehalose glasses formed pick up water as the humidity rises and thus reduce the amount of moisture available to disturb the style. Furthermore, the trehalose glasses may act as pore blockers and steri- cally hinder water from reaching certain parts of the hair. Finally, molecular trehalose may itself stabilize the styled confi guration through effects related to hair protein bind- ing (28) and/or structuring water (29). The striking anti-humidity benefi ts as demonstrated in this paper may be a result of one or more mechanisms described above. More work needs to be done to completely resolve the mechanism of action. In summary, here we see a macroscopic anti-humidity benefi t at the hair array level that seems intimately related to the water uptake and solid state polymorphism of trehalose. Clearly, glassy trehalose regulates moisture in the fi ber and affects the viscoelastic behavior and subsequent aging characteristics of the hair polymer in some way that, though not fully understood, seems to be related to the water uptake properties of this form of trehalose. We think that the presence of the trehalose glass and its ability to regulate moisture in the hair is the major contributing factor for the anti-humidity effect. CONCLUSION Hair treated with trehalose and heat-straightened shows long-lasting hair style reten- tion even at high humidity compared to hair treated with water, provided that the conditions at the style creation stage are suitable, i.e., low-humidity (50%) condi- tions. The formation of trehalose glasses in situ during the heat straightening process on hair treated with trehalose may be responsible for the anti-humidity effect seen. Treha- lose glasses regulate moisture in the fi ber at high humidity, giving longer-lasting style benefi ts. ACKNOWLEDGMENTS The authors thank Janet Cotterall for the initial switch work. REFERENCES (1) N. K. Jain and I. Roy, Effect of trehalose on protein structure, Protein Sci., 18, 24–36 (2009). (2) A. D. Elbein, Y. T. Pan, I. Patuszak, and D. Carroll, New insights on trehalose: A multifunctional mole- cule, Glycobiology, 13(4), 17R–27R (2003). (3) J. G. Streeter, Effect of trehalose on survival of Bradyrhizobium japonicum during desiccation, J. Appl. Micro- biol., 95, 484–491 (2003). (4) N. Benaroudj, D. H. Lee, and A. L. Goldberg, Trehalose accumulation during cellular stress protects cells and cellular proteins from damage by oxygen radicals, J. Biol. Chem., 276(26), 24261–24267 (2001). (5) Y. Nie, J. J. de Pablo, and S. P. Palecek, Platelet cryopreservation using a trehalose and phosphate formulation, Biotech. Bioeng., 92(1), 79–90 (2005). (6) J. H. Crowe, L. M. Crowe, A. E. Oliver, N. M. Tsvetkova, W. F. Wolkers, and F. Tablin, The trehalose myth revisited: Introduction to a symposium on stabilization of cells in the dry state, Cryobiology, 43, 89–105 (2001). (7) W. F. Wolkers, N. J. Walker, Y. Tamari, F. Tablin, and J. H. Crowe, Towards a clinical application of freeze-dried human platelets, Cell Preserv. Technol., 1(3), 175–188 (2003). (8) J. K. Kaushik and R. Bhat, Why is trehalose an exceptional protein stabilizer? An analysis of the thermal stability of proteins in the presence of the compatible osmolyte trehalose, J Biol. Chem., 278(29), 26458– 26465 (2003).

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