As a contribution for future iGEM Teams, we want to show you how to synthesize a mesocellular silica foam (MCF) to immobilize enzymes. Through immobilization, the stability of the enzymes increase regarding pH-value and temperature. We immobilized Laccases so they can be reused and are not released into the environment.
Some safety aspects are really important for the synthesis of the MCF. Hydrochloric acid is toxic in its gaseous phase. This is why it is important to neutralize the evaporated hydrochloric acid in sodium hydroxide solution. The whole experiment is done under an exhaust hood. Furthermore, there must be special caution while working with Mesitylene and NH4F, these chemicals are toxic and harmful. Wearing gloves and safety goggles is recommended. Wash your hands directly after coming in contact with these chemicals.
The experiment was performed in a 500 ml three-necked flask. For permanent reflux a return condenser was used and for easier addition a dropwise funnel was used. Due to the heating up of hydrochloric acid, a washing flask with sodium hydroxide solution was used to neutralize the evaporated hydrochloric acid.
To synthesize the MSF 8 g Pluoronic P123 was dissolved in 294.25 ml HCl solution (11.75 ml HCl in 282.5 ml water). After the Pluoronic P123 was dissolved completely, 13.88 ml Mesitylene and 93.4 mg NH4F were added, the mixture was stirred for one hour at room temperature. Afterwards 18.14 ml TEOS were added dropwise to the mixture and stirred for 20 hours at 40°C. The next day the temperature was increased to 100°C and again stirred for 24 hours. The solid was filtered and washed with Ethanol. Afterwards the MSF was dried overnight at 60°C.
Afterwards the MSF was observed by a scanning electron microscope. Where we could see the size of the pores, which are 24 to 30 nm.
