Transcriptional regulatory proteins as biosensing tools.

We have developed sensing systems employing different classes of transcriptional regulatory proteins genetically and chemically modified to incorporate a fluorescent reporter molecule for detection of arsenic, hydroxylated polychlorinated biphenyls (OH-PCBs), and cyclic AMP (cAMP). These are the first examples of optical sensing systems based on transcriptional regulatory proteins.

ClcR-based biosensing system in the detection of cis-dihydroxylated (chloro-)biphenyls.

Polychlorinated biphenyls (PCBs) are a group of organic pollutants that are persistent when released into the environment. Among the metabolites of PCBs, dihydroxylated PCBs are also considered as toxic compounds. Various studies have shown that dihydroxylated PCBs affect the reproductive, immune, nervous, and endocrine systems.

Novel reporter gene in a fluorescent-based whole cell sensing system.

A common problem encountered when using fluorescence detection in real samples analysis is that the matrix may contain compounds that autofluorescence or that can be excited at the wavelengths of commonly employed fluorescent reporter molecules. This causes an increase in background fluorescence, which in turn tends to compromise the detection limits of the system. To address this issue, we investigated the use of a reporter enzyme that produces fluorescent compounds, which can be excited at wavelengths that are not commonly encountered in compounds present in real samples.

Development of a set of simple bacterial biosensors for quantitative and rapid measurements of arsenite and arsenate in potable water.

Testing for arsenic pollution is commonly performed with chemical test kits of unsatisfying accuracy. Bacterial biosensors are an interesting alternative as they are easily produced, simple, and highly accurate devices. Here, we describe the development of a set of bacterial biosensors based on a nonpathogenic laboratory strain of Escherichia coli, the natural resistance mechanism of E.

Internal response correction for fluorescent whole-cell biosensors.

Whole-cell biosensors based on reporter genes are finding a variety of applications in analytical chemistry. Despite their ability to selectively recognize the analyte in a complex mixture, few applications of such sensing devices to real sample analysis are reported. This is mainly due to nonspecific effects on the biosensor response caused by components of the sample matrix and by environmental changes.