A Phospho-Directed Macroporous Alumina−Silica Nanoreactor with Multi-Functions

Abstract

A phospho-directed nanoreactor with multiple functions is reported. Alumina-functionalized macroporous ordered silica foams (Al-MOSF) have been developed with large pore size, high pore volume (1.6 cm(3)/g), and a surface area of 186 m(2)/g rich in coordination unsaturated Al species, which can be used as phospho-directed nanoreactors for integrated in situ digestion and in situ phosphoisolation. By directly adding Al-MOSF to the conventional in-solution digestion system, both enzymes and proteins are quickly enriched in the macropores of the reactor to achieve a fast proteolysis without increasing the enzyme/protein concentration or using a preimmobilization process, thus the digestion time and the cost can be greatly reduced. Meanwhile, due to the chemo-affinity between alumina and phosphor groups, the Al-MOSF reactor can in situ isolate specific products of the enzymatic reaction (i.e., phosphopeptides) and release the nonspecific peptides to the solution. This strategy is simple, efficient, and successfully applied in the detection of phosphoproteins in real samples.