In this presentation, an overview will be provided of the relative importance of electrostatic and hydrophobic interactions in cell membrane models represented by phospholipid Langmuir monolayers, for the specific case of chitosans. These polysaccharides have many biological applications that depend on the interaction with the cell membrane. In various pieces of work, our group found that the positively charged chitosan interacts more strongly with negatively charged phospholipids [1], including selectivity in removal of some proteins from the air/water interface [2]. However, the chitosan action is not based solely on electrostatic interactions, which was clearly demonstrated in a comparison with a synthetic cationic polyelectrolyte whose charged groups are the same as in chitosan, but affected Langmuir monolayers to a much lower extent [3]. Of particular importance in the effects on monolayers is the change in elasticity which is maximized for low molecular weight chitosans [4] owing to a combination of hydrophobic interactions and ease with which chitosan chains can penetrate the hydrophobic region of the phospholipid monolayers. Taken together, these results may serve for assisting the design of chitosan derivatives with tailored physicochemical properties leading to optimized bactericide and antimicrobial activity. [1] PAVINATTO, F.J.; CASELI, L.; OLIVEIRA JR., O.N.; Biomacromolecules, 11, 1897�1908 (2010).[2] Caseli L.; Pavinatto, F.J.; Nobre, T.M.; Zaniquelli, M.E.D., Viitala, T.; Oliveira Jr, O.N.; Langmuir, 24, 4150-4156 (2008).[3] PAVINATTO, A.; PAVINATTO, F.J.; BARROS-TIMMONS, A.; OLIVEIRA JR., O.N.; ACS Appl. Materials and Interfaces, 2, 246-251 (2010).[4] PAVINATTO, A.; PAVINATTO, F.J.; DELEZUK, J.A.M.; NOBRE, T.M.; SOUZA, A.L.; CAMPANA-FILHO, S.P.; OLIVEIRA JR., O.N.; Coll. Surf. B, 104, 48-53 (2013).

Electrostatic and hydrophobic interactions between chitosans and Langmuir monolayers mimicking cell membranes

247th National Meeting (2014)

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