METHODS AND COMPOSITIONS FOR DISRUPTING BIOFILM UTILIZING CHITOSAN-DERIVATIVE COMPOUNDS

1 . A method of disrupting (e.g., reducing the viscosity of, or dissolving) a preformed biofilm in a subject, the method comprising:

administering to the subject an effective amount of a composition comprising a soluble derivatized chitosan wherein the soluble derivatized chitosan when administered contacts the preformed biofilm, thereby disrupting (e.g., reducing the viscosity of, or dissolving) the preformed biofilm;

wherein the derivatized chitosan comprises a chitosan of the following formula (I):

wherein:

n is an integer between 20 and 6000; and

each R 1 is independently selected for each occurrence from hydrogen, acetyl, and a group of formula (II):

or R 1 , when taken together with the nitrogen to which it is attached, forms a guanidine moiety,

wherein R 2 is hydrogen or amino; and

R 3 is amino, guanidino, C 1 -C 6 alkyl substituted with an amino or guanidino moiety, or a natural or unnatural amino acid side chain,

wherein at least 25% of R 1 substituents are H, at least 1% of R 1 substituents are acetyl, and at least 2% of R 1 substituents are a group of formula (II).