Advanced Nanosensors for Environmental Monitoring

Nanoparticle-enhanced chemical and biosensors offer dynamic and quantitative analysis of toxic compounds in drinking water with potentials to provide rapid, ultrasensitive, and accurate risk assessment. We have developed a number of nanostructured materials as candidates for assessing the occurrence of water contamination. These include polyamic acid-metal nanoparticle composite membranes, polyoxy-dianiline membranes, sequestered metal nanoparticles within electroconducting polymers, and underpotential deposition of metal films onto solid electrodes. These materials have been utilized to design advanced sensors and have also been integrated with conventional instrumental techniques such as flow injection analysis (FIA), liquid chromatography (LC), and gas chromatography (GC). The resulting nanostructured sensors have been tested for the detection and identification of bacteria based on antibiotic susceptibility, multiarray electrochemical sensor with pattern recognition techniques, as well as for metal-enhanced detection of DNA-DNA, DNA-toxin, and DNA-drug interactions. The detection of cyanobacteria microcystis (M) spp and other toxins have also been reported. These sensors coupled with pattern recognition have provided reliable detection, classification, and differentiation of bacteria at subspecies and strain levels. Most of these sensors have shown good-to-excellent pathogen recovery efficiencies as well as a reasonable efficacy for sensing contaminants from water in controlled laboratory experiments.This chapter focuses on some of these novel approaches as well as the fundamental scientific questions involved in this emerging area of research. Advanced nanosensors will be described with respect to the mechanism of molecular recognition, material design, and characterization, sensing procedure and efficiency as well as potential application for improving water quality. The specific evaluation of these sensors will be described in terms of speed, simplicity, and cost for rapid and reliable measurements of some environmental contaminants such as pathogenic bacteria, endocrine disruption chemicals, cyanobacteria, and organophosphate pesticides.