Artículos de revistas
Electrostatic Interactions Are Not Sufficient to Account for Chitosan Bioactivity
Fecha
2010Registro en:
ACS APPLIED MATERIALS & INTERFACES, v.2, n.1, p.246-251, 2010
1944-8244
10.1021/am900665z
Autor
PAVINATTO, Adriana
PAVINATTO, Felippe José
BARROS-TIMMONS, Ana
OLIVEIRA JUNIOR, Osvaldo Novais de
Institución
Resumen
Recent studies involving chitosan interacting with phospholipid monolayers that mimic cell membranes have brought molecular-level evidence for some of the physiological actions of chitosan, as in removing a protein from the membrane. This interaction has been proven to be primarily of electrostatic origin because of the positive charge OF chitosan in low pH solutions, but indirect evidence has also appeared of the presence of hydrophobic interactions. In this study, we provide definitive proof that model membranes are not affected merely by the charges in the amine groups of chitosan. Such a proof was obtained by comparing surface pressure and surface potential isotherms of dipalmitoyl phosphatidyl choline (DPPC) and dipalmitoyl phosphatidyl glycerol (DPPG) monolayers incorporating either chitosan or poly(allylamine hydrochloride) (PAH). As the latter is also positively charged and With the same charged Functional group as chitosan, similar effects should be observed in case the electrical charge was the only relevant parameter. Instead, we observed a large expansion in the surface pressure isotherms upon interaction with chitosan, whereas PAH had much smaller effects. Of particular relevance for biological implications, chitosan considerably reduced the monolayer elasticity, whereas PAH had almost no effect. it is clear therefore that chitosan action depends strongly either on its functional uncharged groups and/or on its specific conformation in solution.