ABSTRACT
A portable chemical sensing system that integrates sample preconcentration, separation and detection as well as wireless communication functionalities into a compact, wearable format can provide continuous and real-time monitoring of volatile organic compounds in the environment. The sensing modality relies on tuning forks coated with molecularly imprinted polymers that, in conjunction with sample preconcentration, offer selective detection down to parts-per-billion levels. The use of capillary columns allows individual components of complex mixtures to be detected at these highly sensitive levels even in the presence of interferents. The wireless capability facilitates the utilization of a paired smartphone as the user interface as well as a vehicle for additional processing and storage of the measured data. This integrated approach offers a cost-effective and reliable platform for personal exposure assessment.
Subject(s)
Air Pollutants/analysis , Chemistry Techniques, Analytical/instrumentation , Environmental Monitoring/instrumentation , Volatile Organic Compounds/analysis , Cell Phone , Environmental Monitoring/methods , Humans , Limit of Detection , Molecular Imprinting , Polyethylene Glycols/chemistry , Wireless TechnologyABSTRACT
Real-time detection of trace chemicals, such as explosives, in a complex environment containing various interferents has been a difficult challenge. We describe here a hybrid nanosensor based on the electrochemical reduction of TNT and the interaction of the reduction products with conducting polymer nanojunctions in an ionic liquid. The sensor simultaneously measures the electrochemical current from the reduction of TNT and the conductance change of the polymer nanojunction caused from the reduction product. The hybrid detection mechanism, together with the unique selective preconcentration capability of the ionic liquid, provides a selective, fast, and sensitive detection of TNT. The sensor, in its current form, is capable of detecting parts-per-trillion level TNT in the presence of various interferents within a few minutes.
Subject(s)
Conductometry/instrumentation , Electrochemistry/methods , Environmental Monitoring/instrumentation , Environmental Monitoring/methods , Nanotechnology/methods , Polymers/chemistry , Chromatography, High Pressure Liquid , Electrolytes , Explosive Agents , Ions , Spectroscopy, Fourier Transform InfraredABSTRACT
We report the unambiguous detection of a sequence of Hepatitis C Virus (HCV) at concentrations down to the fractional pM range using Single Wall Carbon Nanotube (SWNT) Field Effect Transistor (FET) devices functionalized with Peptide Nucleic Acid (PNA).
Subject(s)
Hepacivirus/genetics , Nanotubes, Carbon , RNA, Viral/analysis , Transistors, Electronic , Electrochemistry/methods , Microchemistry/methods , Nanotechnology , Peptide Nucleic AcidsABSTRACT
A method to functionalize single-walled carbon nanotubes (SWNTs) in a field-effect transistor (FET) device for the selective detection of heavy-metal ions is presented. In this method, peptide-modified polymers were electrochemically deposited onto SWNTs and the selective detection of metal ions was demonstrated by choosing appropriate peptide sequences. The signal transduction mechanism of the peptide-modified SWNT-FETs has also been studied.
