Synthesis and sorption properties of heparin imprinted zeolite beta/polydopamine composite nanoparticles

Heparin-specific molecularly imprinted polymer (MIP) using a nano-layer of polydopamine was synthesized at the surface of zeolite Beta nanoparticles. The Brunauer–Emmett–Teller (BET) surface area of MIP is about 347.23 m2/g with a mean pore diameter of nearly 8 nm, while the corresponding features for the non-imprinted polymers (NIP) are 255.50 m2/g and 10.17 nm, respectively. The transmission electron microscope (TEM) results revealed that the thickness of the polydopamine shell in NIP is less than that of MIP. The static and selective sorption of heparin along with its sorption kinetics were investigated at physiological pH. The results demonstrated that the sorption isotherm of heparin using NIP follows the Langmuir isotherm model, suggesting the monolayer sorption. However, the Freundlich model presented a better description of heparin sorption by MIP, which indicates the presence of high-affinity binding sites and surface heterogeneity. The pseudo-second-order model demonstrated satisfactorily the kinetic data, indicating the secondary reaction of heparin with imprinting sites through chemical sorption. The selectivity of MIP was assessed using sodium alginate as a similar compound, providing imprinting factor and selectivity coefficient of ca. 10.37 and 9.66, respectively. Finally, the reusability of MIP was studied in three sequential sorption-desorption cycles. Interestingly, after 3 cycles, MIP did not exhibit a significant reduction in binding capacity. •Heparin molecularly imprinted nanoparticles was synthesized by surface imprinting.•Surface coating of zeolite Beta nanoparticles was performed via polydopamine.•Molecularly imprinted nanoparticles were developed for detection of heparin.•The nanoadsorbents have high selectivity and binding capacity for heparin.•Reusability of the synthesized nanoadsorbents was at a desirable level.