Sol–gel process for vegetal cell encapsulation

A sol–gel process was carried out at room temperature to obtain porous silica matrixes for entrapment of vegetal cells. The process uses sodium silicate as a precursor rather than alkoxides to avoid generation of by-products that is detrimental to Chlorella vulgaris cells. The influence of several factors influencing the gelification was explored to optimize the encapsulation process. The technique produces a transparent matrix and is then very suitable for vegetal cell entrapment since they require light for their photosynthetic activity. Activity of the algal cells was determined by measurement of the intensity of fluorescence emission at 682 nm. This measurement also allowed to evaluate the efficiency of the immobilization technique and assess the long-term activity of the encapsulated whole cells.