A hormone-free women's contraceptive with no side
effects is one promising use for a new technique
developed by Thomas Crouzier's group at KTH Royal
Institute of Technology in Stockholm.
The distribution of chitosan over a mucin drop is
shown in flourescence. Image: Thomas Crouzier
The approach consists of cross-linking the mucus gel
with chitosan, a type of polysaccharide derived from
chitin, the substance that develops in the hard
outer shells of crustaceans such as shrimp and
The material tightens the mucin polymer mesh barrier
which lines the mucosal epithelium of our body’s
cavities, says Thomas Crouzier, a researcher at KTH
Royal Institute of Technology in Stockholm.
The mucus gel covers the wet epithelia that forms
the inner lining of the body.
It constitutes our first line of defense protecting
the body from infections and other deleterious
Failure of the mucus barrier can lead to the
inflammation of the mucosa which is the problem
behind inflammatory bowel diseases, rhinitis, acid
reflux and other syndromes.
The polymer which they use slowed the diffusion of
dextran polymers and cholera protein through the
mucous gels, the researchers reported in the recent
issue of Biomacromolecules.
And in the cervix, the usually impervious mucous
barrier naturally becomes slack during ovulation,
allowing sperm to penetrate and fertilize eggs.
“The polymeric material can close this possibility,
and could prevent fertilization from occurring,”
Crouzier says. “In this way, we get a contraceptive
that is not based on hormones and has no side
These results uncover a new use for low molar mass
mucoadhesive polymers such as chitosans as
noncytotoxic mucosal barrier enhancers that could be
valuable in the prevention and treatment of mucosal
Through his private company, Crouzier is working
toward bringing a product to market. He says the
contraception could be applied as a small vaginal
capsule that quickly dissolves. The blocking effect
has been shown to be fast, within minutes, he says.
The 100 percent bio-based material produces no
unwanted side effects because it only modifies the
superficial mucus layer, whether used in
contraception or other therapies, such as treatment
of ulcers in mucous membranes and inflammatory bowel
The researchers have also worked to improve other
properties of mucous membranes, such as lubrication
Previous work by the research team led to progress
in treating dry mucous membranes.
Crouzier is the leader of the Biopolymers for Life
research group at KTH’s School of Engineering
Sciences in Chemistry, Biotechnology and Health, in
the Department of Chemistry and the division of
For more information
Reinforcing Mucus Barrier Properties with Low Molar
Biopolymers for Life research group
KTH’s School of Engineering Sciences in Chemistry,
Biotechnology and Health
Division of Glycoscience