Heparinized Dendritic Mesoporous Silica Nanoparticles for the Selective Adsorption and Isolation of Thrombin

A novel solid-phase extractant, heparinized dendritic mesoporous silica nanoparticles (DMSNs-NH-Hep), is prepared by grafting heparin onto amino-terminated dendritic mesoporous silica nanoparticles. DMSNs-NH-Hep exhibit a spherical morphology and possesses a unique central-radial pore structure with a BET surface area and pore volume of 230.81 m² g^-1 and 1.23 cm³ g^-1, respectively. Due to the specific interaction between heparin and thrombin, DMSNs-NH-Hep demonstrate favorable adsorption selectivity and a rapid adsorption rate toward thrombin. In PBS buffer at pH 7.4, an adsorption efficiency of 81.1% for 0.1 mL of thrombin solution (85 U/mL) is obtained by using 0.06 mg of DMSNs-NH-Hep in 3 min. An adsorption capacity of 237.35 U mg^-1 is derived for thrombin. The captured thrombin can be readily eluted by a 0.3% sodium dodecyl sulfate (SDS) solution with an elution efficiency of 80.4%. The potential of DMSNs-NH-Hep in complex sample analysis is confirmed through the selective isolation of thrombin from fetal bovine serum and bovine plasma spiked with the thrombin standard, as confirmed by sodium dodecyl sulfate-polyacrylamide (SDS-PAGE) analysis.