Trypsin Immobilization on Thiol Functionalized Mesoporous Silicas Prepared Using Castor Oil Template

Abstract

Mesoporous thiol modified silicas have been prepared using castor oil as a templating agent. The preparation was done through a co-condensation of 3-mercaptopropyltriethoxysilane and tetraethylorthosilicate in a 1:4 molar ratio. Physisorption studies showed that the prepared mesoporous silicas have an average pore diameter of 9 nm, pore volume of 1.0336 cm³/g and surface areas of up to 605 m²/g. FTIR confirmed the attachment of thiol groups on the surface of the prepared mesoporous silica as evidenced with an absorption band at around 2600 cm^–1. SEM images indicated agglomeration of the prepared particles. The prepared thiol modified silicas were successfully immobilized with trypsin enzyme. The immobilized trypsin enzyme was stable and active for hydrolysis of N-α-benzoyl-DL-arginine-p-nitroanilide (BAPNA) substrate. Re-use studies of the immobilized trypsin showed that the enzyme could be reused up to four cycles without significant loss of activity.