Topic: Chemistry
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The Commercial Future of Chitosan
A major advantage is chitosan's antimicrobial properties, which have been acknowledged since the 1970's but only recently probed in detail. Ri- cardo Muzzarelli, a pioneer of chitosan research, observed in 1990 that chitosan drastically inhibited the growth of 298 bacterial cultures.
Chitosan is not a universal preservative, however. To determine its actual antimicrobial effectiveness when combined with food, the same study added starch, whey protein, table salt, or oil (representing common food components) before inoculating chitosan solutions with different microbe strains. At low concentrations of food additives and for all concentrations of oil, chitosan continued to inhibit microbial growth, but at certain thresholds for starch, protein, and salt (30%, 10%, and 1%, respectively), chitosan had no effect. The negatively charged groups in starch and protein most likely competed with the bacterial cell walls for interaction with chitosan, while salt, which dissociates into positive and negative ions, could have formed ionic bonds with both chitosan and bacterial membranes.
In addition to wrapping food, chitosan can be a component of gene therapy, which targets genetic disorders with DNA-based treatments instead of conventional drugs. Chitosan nanospheres, tiny hollow globes under a micron in diameter, readily encapsulate plasmid DNA that is engineered to encode specific proteins (7). Since chitosan is non-toxic, it shows special promise as an oral vehicle for DNA vaccines, and its pH-sensitivity allows for controlled release of the contents. In the acidic environment of the stomach, chitosan..
Source: www.hcs.harvard.edu
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