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.