Functionalized nanoporous materials for volatile metabolites monitoring with direct optical transduction

A noninvasive and low cost colorimetric test is proposed to detect microorganisms in complex media via volatile metabolites released by enzymatic activity. The sensor is based on a hybrid organic-inorganic nanoporous xerogel. This transparent and colorless silica matrix traps and concentrates targeted volatile metabolites which are then detected by absorbance measurements. Ortho-nitrophenol was chosen as a volatile metabolite. At a first stage, the trapping efficiencies of various functionalized xerogels were compared in order to optimize the detection of ortho-nitrophenol. As a second step, we used xerogels with the best composition to detect E. coli cells in blood samples.