title: In vivo evaluation of lateral lipid chain packing in human stratum corneum.
abstract: OBJECTIVE
  The matrix of intercellular lipids (ICL) of stratum corneum (SC) plays an important role in the barrier function of SC. It is important to understand the structure of the ICL matrix for dermatology and cosmetic science. Several methods exist for the analysis of the structure; however, it is difficult to conduct these analyses noninvasively.
  
  
  METHODS
  We have developed a method for the analysis of the lateral packing of ICL using Raman spectroscopy. As a proof-of-principle experiment, we prepared a human SC sheet sample and analyzed its structure by the proposed method and by a conventional method involving X-ray diffraction. We compared the results of both methods. In addition, we applied the proposed method to living human skin, and we analyzed the lateral packing of ICL of SC taken from three separate body sites.
  
  
  RESULTS
  The results of our method corresponded to those of the conventional method. We detected regional differences of ICL lateral packing using our method in vivo. The results indicated that the packing of ICL in SC taken from the forearm and upper arm are more ordered than that taken from the cheek.
  
  
  CONCLUSIONS
  The results verify that our developed method allows the evaluation of the lateral packing of ICL inside the SC layer of the skin in vivo. Using this method, we can detect regional differences of SC samples taken from various body sites.
authors.affiliation: Analytical Science Research Laboratories, Kao Corporation, Tochigi, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kikuchi
authors.forename: T
authors.initials: T
authors.lastname: Aosaki
authors.forename: K
authors.initials: K
authors.lastname: Bito
authors.forename: S
authors.initials: S
authors.lastname: Naito
authors.forename: Y
authors.initials: Y
authors.lastname: Katayama
mesh_terms: D000005:Abdomen; D000328:Adult; D001132:Arm; D002610:Cheek; D004817:Epidermis / Q000737:chemistry*; D005260:Female; D006801:Humans; D008055:Lipids / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013059:Spectrum Analysis, Raman / Q000295:instrumentation* / Q000379:methods*; D013696:Temperature; D014018:Tissue Distribution
chemical_list: D008055:Lipids
keywords: Raman spectroscopy; in vivo; intercellular lipids; lateral lipid chain packing; stratum corneum