Macroporous magnetic agarose particles (MMAPs) were prepared with calcium carbonate as the porogent by the water-in-oil suspension thermal regeneration method. MMAPs with good sphericity and appropriate particle size were obtained. The physical properties of the beads were determined and it was found that the water content (92.1%), porosity (94.4%) and mean pore diameter (120.1 nm) of the MMAPs were higher than those for the normal magnetic particles, indicating successful generation of macropores after calcium carbonate addition. Compared with normal magnetic particles, the mass transfer of biomolecules in MMAPs was remarkably enhanced. Finally, MMAPs were modified with 5-amino-benzimidazol (ABI) ligand and the adsorption capacity of IgG reached 153 mg/mL, higher than that of the normal magnetic particles (126 mg/mL). Moreover, adsorption behavior of MMAPs to IgG was little changed after twenty-five recycled use. Hence, MMAPs prepared herein showed great potential for bioseparation.
The performance of chromatographic media affects the efficiency of purification. In this study, based on a T-type microfluidic droplet generation system, agarose microspheres with large pore size and high load were prepared by adjusting the viscosity of a 4% agarose solution to 70 mPa·s at high temperature. Optical microscopy revealed that the self-made agarose microspheres had a good spherical structure with an average particle size of 82.81 μm and a CV value of 0.0576. Subsequently, the stability and mechanical strength of the self-made agarose microspheres were improved by cross-linking and activation with epichlorohydrin. After the cross-linking and activation, the agarose microspheres were grafted with Protein A to make it have specific adsorption capacity for IgG. The adsorption capacity of the self-made agarose microspheres grafted with Protein A for IgG was 87 mg/g. In the complex serum environment, the agarose microspheres grafted with Protein A still maintained good IgG adsorption capacity and selectivity, demonstrating their potential in practical applications. This study demonstrates the great potential of microfluidic technology in the design and preparation of bio-separation media. By precisely controlling the particle size and pore size of the microspheres, the purification efficiency and selectivity can be significantly improved, providing a new solution for the efficient purification of bio-products. Graphical abstract
In the present work, mixed-mode chromatography adsorbents grafted with dextran of different molecular weight were prepared. Compared to non-grafted adsorbent (BA-6B), the morphology of dextran-grafted adsorbents (BA-6B-Ts) did not change significantly, while the water content ( ω ), porosity ( P ) and pore volume ( V ) decreased. Static adsorption, salt tolerance and dynamic adsorption behaviors of adsorbents BA-6B-Ts against BSA/IgG were studied. Compared to adsorbent BA-6B, adsorbents BA-6B-Ts had higher saturated adsorption capacity ( Q m ) toward BSA/IgG, especially for BA-6B-T20, the Q m values toward BSA and IgG increased by 32.8% and 39.5%, respectively. Adsorbents BA-6B-Ts showed enhanced salt tolerance toward BSA, and relatively weaker salt tolerance toward IgG. The relative adsorption capacity of BA-6B-T20 was 66.7% at 0.1 mol/L NaCl and 39.2% at 0.5 mol/L NaCl, higher than those of BA-6B. Moreover, for both BSA and IgG, the effective pore diffusivity ( D e ) of BA-6B-Ts was higher than that of BA-6B. D e values of BA-6B-T20 toward BSA and IgG increased by 77% and 139% compared to BA-6B, respectively. Dynamic binding capacities (DBCs) of BA-6B-Ts were also improved. DBC of BSA and IgG on BA-6B-T20 were 25.6% and 46.5% higher than those on BA-6B. The possible mechanisms for the above difference in adsorption behavior of dextran-grafted adsorbents toward BSA/IgG were discussed, providing some insights into protein adsorption and mass transport for dextran-grafted MMC resins.
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