Hydrophilicity Modification Of Macroporous PGMA Microspheres And Its Application In Separation And Purification

The macroporous PGMA microspheres is hydrophobic,thus non-specific adsorption for protein on its surface uaually occured,and the microspheres were prepared with low loading.In this paper,the following issues were explored:PGMA microspheres were used as matrix,and dextran was grafted onto the surface of the microspheres by epoxy resin in organic solvent DMSO,and then,by means of the allyl activation method,the surface of the coating was coated with a plurality of hydrophilic groups OH so as to achieve the purpose of hydrophilic modification.The fourier transform infrared spectroscopy,scanning electron microscopy and atomic force microscopy were used to characterize the chemical composition and surface morphology of the microscope before and after modification.The fourier transform infrared spectroscopy showed that the dextran was grafted onto the microspheres.The scanning electron microscopy and atomic force microscopy showed that the morphology of the microspheres was not changed.Nonspecific adsorption test showed that,after modification,the nonspecific adsorption changed from 60% to about 2%,close to the nonspecific adsorption of agarose microspheres.Contact angle decreased from 153 to about 0 degrees.It had strong hydrophilic.Hydrophilic modified PGMA microspheres were prepared into chromatographic medium with alkali Protein A by epichlorohydrin epoxy activation,and we improved the preparation scheme,and the loading and properties were characterized.The scanning electron microscopy and pressure velocity curves showed that the flow performance was not changed before and after modification.The relationship between the epoxy value,the ligand density and the loading was investigated.The results showed that with the epoxy value increased,the ligand density increased,while with the ligand density increased,the load increased first and then decreased.When the ligand density was 4.52 mg/mL,the dynamic load reached the maximum value of 16.1 mg/m L.The dynamic load of the media at different retention time was investigated,and the results showed that with the retention time was shortened from 5min to 1 min,the dynamic load of medium only decreased by 13%,which indicated that it had a certain potential for rapid separation and purification.The hydrophilic modified PGMA microspheres were prepared into anion exchange media DEAE.The morphology before/after modification was characterized.The influence of the pore size and the density of the ligand on the dynamic load was also investigated.The results showed that with the pore size increased,the load increased,while with the density of the ligand increased,the loading of the medium increased and then decreased.The dynamic load of the media at different retention time was investigated,and the results showed that with the retention time was shortened from 5 min to 1 min,the dynamic load of medium only decreased by 18%,which indicated that it had a certain potential for rapid separation and purification.