ABSTRACT
GHK (Gly-His-Lys), a natural peptide found in human skin and plasma, has been widely used in the cosmeceutical and pharmaceutical fields. The hydrophilic GHK and GHK-Cu are limited in their abilities to penetrate deeply into skin; because of this, various strategies for their skin delivery have been developed. In this investigation, Arg4 was conjugated with GHK to get heptapeptide, GHK-R4, and then in vitro antiwrinkle activity and transdermal delivery were compared between GHK and GHK-R4. Notably, Arg4 conjugation accelerated the cellular penetration of GHK both in vitro and in vivo. Furthermore, higher in vitro antiwrinkle activity and collagen biosynthesis was obtained with GHK-R4 at much lower doses than with control R4-free GHK. The enhanced activity and delivery of GHK-R4 might be due to the cell penetrating ability and matrix metalloproteinase (MMP) inhibitory activity of R4 itself.
Subject(s)
Oligopeptides/pharmacology , Peptides/chemistry , Skin Aging/drug effects , Administration, Cutaneous , Cell Line , Cell-Penetrating Peptides/chemistry , Cell-Penetrating Peptides/pharmacology , Collagen/metabolism , Humans , Matrix Metalloproteinases/metabolism , Oligopeptides/chemistryABSTRACT
Enrichment of circulating tumor cells (CTCs) from whole blood is very challenging due to its rarity. We have developed a new CTC enrichment method using a microfabricated filter. The filter was designed to fractionate tumor cells by cell size and optimized to have high porosity and proper pore distribution. When cancer cells were spiked in whole blood, the average recovery rate was 82.0 to 86.7% and the limit of detection by filtration process was approximately 2 cancer cells in a testing volume of blood. The results indicate that the microfabricated filter-based enrichment would be useful to retrieve and analyze CTCs in practice.
