Zıt yüklü iki-yarı esnek biyopolimerin kompleks koakservasyonu

Complex coacervation is the spontaneous liquid-liquid phase separation between two oppositely charged macromolecules. Complex coacervation has been used in various applications such as food industry, pharmaceutical industry, cosmetics, biotechnology, and tissue engineering. The first chapter of this thesis includes the examination of thermodynamic characteristics of the interaction between two biopolymers, hyaluronic acid (HA) and chitosan (CHI) under different conditions such as ionic strength, pH, temperature, and molecular weight by using Isothermal titration calorimetry (ITC). The results showed that dominant driving force for HA-CHI complexation was the entropy gain due to counterion release, as indicated by the higher contribution of T∆S_IP values to ΔG than enthalpy for all conditions. In second chapter of this thesis, meso-structure of complex coacervation, protein/polyelectrolyte (HA-BSA) and polyelectrolyte/polyelectrolyte (HA-CHI) coacervate systems were compared by using small angle neutron scattering (SANS) and noticed that α (power-law exponent) values for both systems depend on the pH due to charge density of polyelectrolytes and protein. Furthermore, radius of gyration of complexes is higher compared to the free protein and polyelectrolyte solutions. In third chapter of this thesis includes the effect of concentration and different salts of Hofmeister series on complex coacervation of HA-CHI and CHI-BSA systems. Turbidity allowed us to determine critical salt concentration where the turbidity started to show a sharp increase. While some salts' effect on the formation of complex coacervation resulted in opposite behavior, some of them showed direct behavior of Hofmeister series.