Effect of pore structure of SBA-15 on immobilization of hemoglobin

Immobilization of hemoglobin (Hb) in SBA-15 with various pore sizes by physical adsorption was studied. The structure changes of mesoporous SBA-15 before and after the immobilization of Hb were characterized by N-2 adsorption isotherms, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Ultraviolet-visible spectroscopy (UV). The results indicate that SBA-15 is a good support for the immobilization of Hb due to its regular structure, large pore diameter, and high surface area. After immobilization of Hb, the regular structure of SBA-15 is still kept, but the pore diameter, pore volume and surface area decrease. With the increase of pore size, the binding amount and leaching amount of Hb increase. There is a maximum binding amount of Hb up to 355.2 mg/g (SBA-15) when pore size is 8.9 nm. It is suggested that the immobilization of Hb depends significantly on the pore size of SBA-15.