Chitosan is a natural, non-toxic and biodegradable, polysaccharide readily obtained from chitin, the main component of the shells of shrimp, lobster and the beak of the octopus and squid.
It is well known for its antimicrobial activity and was studied by scientists in New Jersey for its potential in preventing infection in wounds as well as enhancing the wound-healing process itself by stimulating skin cell growth.
The team, led by Mihaela Leonida of Fairleigh Dickinson University, in Teaneck, New Jersey, published their findings in the peer-reviewed International Journal of Nano and Biomaterials.
Ionic gelation process
They made their chitosan nanoparticles (CNP) using an ionic gelation process with sodium tripolyphosphate.
This process involves the formation of bonds between polymers strands, a so-called cross-linking process. Conducted in these conditions it excludes the need for complex preparative chemistry or toxic solvents.
CNP can also be made in the presence of copper and silver ions, known antimicrobial agents. The researchers' preliminary tests show the composite materials to have enhanced activity against two representative types of bacteria; Staphylococcus saprophyticus and Escherichia coli.
“Understanding the mechanism of inhibition of bacteria by these particles may lead to the preparation of more effective antibacterial agents,” comments the study.
“The team has also demonstrated that the CNP have skin regenerative properties in tests on skin cell fibroblasts and keratinocytes, in the laboratory, which might even have implications for anti-aging skin care products.”
Previous skin care study
It is not the first time the shrimp shell derivative has been the focus of a skin care study. Last year chitosan microparticles were shown to significantly improve the ability of certain antioxidants to permeate the skin.
Catechins are natural antioxidants, commonly found in green tea; however their use in cosmetic products has been limited because they do not permeate the skin well.
Researchers in Thailand evaluated the cutaneous absorption of catechins from an extract of green tea and from a green tea extract–loaded chitosan microparticle.
The researchers performed an in vitro skin permeation study along with a study into green tea metabolism, examining the difference between the normal tea extract and the one loaded with the chitosan microparticle.
The study results suggest that chitosan microparticles significantly improve the ability of catechins to permeate skin.