Phase separation of triton X-100 and bovine serum albumin mixture: Impacts of nature and composition of polyols on associated physicochemical parameters

Bovine serum albumin (BSA) is widely used in tissue engineering and pharmaceutical research. It is readily available as a byproduct of the cattle industry, and collected from blood. In this study, we conducted a physicochemical investigation of the phase separation in a mixture of Triton X-100 (TX-100) and BSA, influenced by various polyols, using the well-established cloud point (CP) determination method. The addition of polyols resulted in a significant reduction in CP values for the TX-100 + BSA mixture. The magnitudes of CP in the experimental system were highly varied with different polyols and followed the order of: CP_H2O+Xylose>CP_H2O+Mannose>CP_{H2O+Arabinose}>CP_H2O+Fructose>CP_H2O+Dextrsoe>CP_H2O+Glucose>CP_H2O+Maltose. Under identical conditions, the system exhibited maximum solubility in the xylose solution and minimum solubility in the maltose solution. The positive ΔG_c⁰ values were acquired in all working medium imply the nonspontaneity of phase transition in the TX-100 + BSA system. At lower polyol contents, the negative values of standard enthalpy (∆H_c⁰) and standard entropy (∆S_c⁰) changes were observed, suggesting that electrostatic forces dominated as the driving force for clouding. At highest employed polyols concentration in some case, the positive values for ∆H_c⁰ and ∆S_c⁰ were achieved, which indicated that hydrophobic interactions likely dominate the phase partitioning of the amphiphile and protein mixture. Additionally, entropy-enthalpy compensation parameters were calculated and analyzed with a rational approach. Molecular docking analysis further demonstrated the presence of hydrogen bonds and hydrophobic interactions between TX-100 and BSA.