title: N-Reacetylated Oligochitosan: pH Dependence of Self-Assembly Properties and Antibacterial Activity.
abstract: Oligochitosan (short chain chitosan) is more soluble in acidic aqueous media than a high molecular weight (MW) chitosan, but its antimicrobial activity decreases with increase in degree of acetylation (DA) and increase in pH above a critical pH threshold point. In the present study, oligochitosans varying in MW were additionally N-acetylated and their self-assembly properties and antibacterial activity toward Staphylococcus aureus and Escherichia coli were investigated in a wide pH range as a function of MW and DA. Light scattering studies reveals that reacetyleted oligochitosan with Mw≤ 11 kDa is completely soluble in alkaline media (up to pH 12.5), if its DA is not less than 16%. Reacetylated chitosans with DA ∼ 30% are solubile in the entire pH range up to 12.5, if their Mwis not higher than 25 kDa, but they aggregate and precipitate from the solution at pH ≥ 8 when their Mwis above 25 kDa. Considering the influence of DA and MW, the antibacterial activity of reacetylated oligochitosans is maximal in the short interval of DA 16-28% at pH 7.4. These results are promising for expanding practical application of oligochitosan in pharmaceutical, cosmetic, and food compositions.
authors.affiliation: A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Russia, Vavilov street 28, Moscow, 119991 Russia.
authors.forename: Inesa V
authors.initials: IV
authors.lastname: Blagodatskikh
authors.affiliation: Kazan Federal University , Kremlyovskaya street 18, Kazan, 420008 Russia.|Kazan Scientific Research Institute of Epidemiology and Microbiology, Bolshaya Krasnaya street 67, Kazan, 420015 Russia.
authors.forename: Sergey N
authors.initials: SN
authors.lastname: Kulikov
authors.affiliation: A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Russia, Vavilov street 28, Moscow, 119991 Russia.
authors.forename: Oxana V
authors.initials: OV
authors.lastname: Vyshivannaya
authors.affiliation: A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Russia, Vavilov street 28, Moscow, 119991 Russia.
authors.forename: Evgeniya A
authors.initials: EA
authors.lastname: Bezrodnykh
authors.affiliation: A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Russia, Vavilov street 28, Moscow, 119991 Russia.
authors.forename: Vladimir E
authors.identifier: http://orcid.org/0000-0002-0036-5873
authors.initials: VE
authors.lastname: Tikhonov
mesh_terms: D000085:Acetates / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D048271:Chitosan / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D058105:Polymerization; D012486:Salmonella typhimurium / Q000187:drug effects
chemical_list: D000085:Acetates; D000900:Anti-Bacterial Agents; D048271:Chitosan