Functionalized Nano-adsorbent for Affinity Separation of Proteins

Thiol-functionalized silica nanospheres (SiO(2)-SH NSs) with an average diameter of 460 nm were synthesized through a hydrothermal route. Subsequently, the prepared SiO(2)-SH NSs were modified by SnO(2) quantum dots to afford SnO(2)/SiO(2) composite NSs possessing obvious fluorescence, which could be used to trace the target protein. The SnO(2)/SiO(2) NSs were further modified by reduced glutathione (GSH) to obtain SnO(2)/SiO(2)-GSH NSs, which can specifically separate glutathione S-transferase-tagged (GST-tagged) protein. Moreover, the peroxidase activity of glutathione peroxidase 3 (GPX3) separated from SnO(2)/SiO(2)-GSH NSs in vitro was evaluated. Results show that the prepared SnO(2)/SiO(2)-GSH NSs exhibit negligible nonspecific adsorption, high concentration of protein binding (7.4 mg/g), and good reused properties. In the meantime, the GST-tagged GPX3 separated by these NSs can retain its redox state and peroxidase activity. Therefore, the prepared SnO(2)/SiO(2)-GSH NSs might find promising application in the rapid separation and purification of GST-tagged proteins.