The synthesis of hydroxyethyl starch 130/0.4-loaded albumin nanoparticles: biocompatibility and interaction mechanism

The nanoplatform for drugs demonstrates favorable stability and high therapeutical advantages in the bloodstream. Here, by using hydroxyethyl starch (HES) 130/0.4 and serum albumin, which were widely used as volume expanders in intravenous therapy, we synthesized a new HES 130/0.4-loaded bovine serum albumin (BSA) nanoparticles and investigated the binding mechanism in the simulated physiological environment with considerations of compatibility. Analysis of the fluorescence quenching data of BSA by HES using the Stern–Volmer equation proved the formation of a 1:1 ground state complex. The binding parameters (ΔS° = 329 J mol⁻¹ K⁻¹, ΔH° = 6.38 × 10⁵ J mol⁻¹, and ΔG = − 3.04 × 10⁵ J mol⁻¹) at body temperature manifested that the interaction was exothermic and driven by hydrophobic interactions. The binding distance was calculated as 2.73 nm and showed a high possibility of Förster resonance energy transfer. The structural alterations of BSA were assessed both qualitatively and quantitatively through the application of 3D/synchronous fluorescence and circular dichroism techniques, respectively, which showed adaptive changes in secondary structures. The results presented in this study offer not only novel ideas of albumin-based NP synthesis, but precise and comprehensive primary data that elucidate the mechanisms of HES-BSA interaction, helping to comprehend its pharmacodynamics in blood.