Determination of the parameters of binding between lipopolysaccharide and chitosan and its N-acetylated derivative using a gravimetric piezoquartz biosensor

- Interaction of lipopolysaccharide with chitosan and its N-acylated derivative was examined.
- Association, dissociation rate constants and affinity for LPS binding with chitosans are determined.
- Affinity of binding N-acylated chitosan with LPS was higher, than the parent chitosan.

The interaction of endotoxin (lipopolysaccharide - LPS) with low molecular weight chitosan (5.5 kDa), its N-acylated derivative and chitoliposomes was studied using a gravimetric piezoelectric quartz crystal microbalance biosensor. The optimal conditions for the formation of a biolayer based on immobilized LPS on the resonator surface and its regeneration were elaborated. The association and dissociation rate constants for LPS binding to chitosans were determined and the affinity constants (Kaf) were calculated based on the data on changes in the oscillation frequency of the quartz crystal resonator. The Kaf values correlated with the ones obtained using other methods. The affinity of N-acylated chitosan binding to LPS was higher than that of the parent chitosan binding to LPS. Based on the results obtained, we suggest that water-soluble N-acylated derivatives of chitosan with low degree of substitution of amino groups could be useful compounds for endotoxin binding and neutralization.