On the temperature dependence of complex formation between chitosan and proteins

TY - JOUR

T1 - On the temperature dependence of complex formation between chitosan and proteins

AU - Kasimova, Marina Robertovna

AU - Valázquez-Campoy, Adrián

AU - Nielsen, Hanne Mørck

PY - 2011/7/11

Y1 - 2011/7/11

N2 - Chitosan is a biocompatible easily degradable polysaccharide, which, because of its positive charge, is able to interact favorably with deprotonated carboxyl groups of proteins. The strength of these charge-charge interactions is generally low, resulting in poor colloidal stability of the complexes. To investigate if other noncovalent forces contribute to stabilizing such systems, we have selected α-lactalbumin, β-lactoglobulin, β-casein, and human growth hormone, characterized by a common acidic pI value (∼5) that ensures their overall negative charge at physiological pH. Binding energetics between chitosan and proteins was studied by isothermal titration calorimetry, whereas the thermal stability was assessed by differential scanning calorimetry. Our data show that colloidal stability of the particles depends on protein identity as well as temperature, indicating the involvement of nonelectrostatic interactions (e.g., hydrophobic effect) as driving forces for the complex formation. This suggests that chitosan-protein drug delivery systems can be improved through preparation process optimization with regard to temperature.

AB - Chitosan is a biocompatible easily degradable polysaccharide, which, because of its positive charge, is able to interact favorably with deprotonated carboxyl groups of proteins. The strength of these charge-charge interactions is generally low, resulting in poor colloidal stability of the complexes. To investigate if other noncovalent forces contribute to stabilizing such systems, we have selected α-lactalbumin, β-lactoglobulin, β-casein, and human growth hormone, characterized by a common acidic pI value (∼5) that ensures their overall negative charge at physiological pH. Binding energetics between chitosan and proteins was studied by isothermal titration calorimetry, whereas the thermal stability was assessed by differential scanning calorimetry. Our data show that colloidal stability of the particles depends on protein identity as well as temperature, indicating the involvement of nonelectrostatic interactions (e.g., hydrophobic effect) as driving forces for the complex formation. This suggests that chitosan-protein drug delivery systems can be improved through preparation process optimization with regard to temperature.

KW - Former Faculty of Pharmaceutical Sciences

U2 - 10.1021/bm200344d

DO - 10.1021/bm200344d

M3 - Journal article

C2 - 21591796

SN - 1525-7797

VL - 12

SP - 2534

EP - 2543

JO - Biomacromolecules

JF - Biomacromolecules

IS - 7

ER -