Electrochemical characterization of self assembled monolayers on flexible electrodes

Self assembled assembled monolayers of amine- and carboxylic acid terminated thiols have been chemisorbed on gold electrodes deposited on flexible polyethylene terephthalate substrates. These devices, being flexible, low cost, and highly resistant could find application in several fields such as the design of implantable biomedical devices and disposable light-weight sensors. Four different molecules have been investigated, namely cysteamine, 12-mercaptododecanoic acid, aminothiophenol, and 3-mercaptopropionic acid, each bearing either an amino or a carboxylic terminal group and different chain lengths. These molecules have been chosen since the SAM they can form could find application as such or constitute the basis for a further modification step. The modified surfaces have been characterized by electrochemical techniques and the surface pK(a) values of the terminal groups have been estimated by impedance titration

Electrochemical characterization of self assembled monolayers on flexible electrodes

Self assembled monolayers of amine- and carboxylic acid terminated thiols have been chemisorbed on gold electrodes deposited on flexible polyethylene terephthalate substrates. These devices, being flexible, low cost, and highly resistant could find application in several fields such as the design of implantable biomedical devices and disposable light-weight sensors. Four different molecules have been investigated, namely cysteamine, 12-mercaptododecanoic acid, aminothiophenol, and 3-mercaptopropionic acid, each bearing either an amino or a carboxylic terminal group and different chain lengths. These molecules have been chosen since the SAM they can form could find application as such or constitute the basis for a further modification step. The modified surfaces have been characterized by electrochemical techniques and the surface pK a values of the terminal groups have been estimated by impedance titration

Ultra-Low Voltage, OTFT-Based Sensor for Label-Free DNA Detection

An organic ultra-low voltage field effect transistor for DNA hybridization detection is presented. The transduction mechanism is based on a field-effect modulation due to the electrical charge of the oligonucleotides, so label-free detection can be performed. The device shows sub-nanometrical detection limit and unprecedented selectivity with respect to single nucleotide polymorphism

Charge sensing by organic charge-modulated field effect transistors: application to the detection of bio-related effects

The ability of field effect transistors (FETs) to detect charge variations on the gate may be exploited for realizing chemo- and bio-sensors. In this paper, we focus our attention on a particular kind of field effect device, named organic charge modulated FETs, whose features can be optimized for charge detection in liquid solutions. The results of the measurement of different bio-related effects are shown. In particular, DNA hybridization and pH detection in liquid media are proposed. Finally, preliminary considerations about the applicability of these devices to the detection of the electrical activity of cells are also provided. The device has considerable potential for being employed as a reliable, high sensitivity, low cost technology for sensing signals derived from living systems

Heavy metal concentrations in natural and human-impacted sediments of Segara Anakan Lagoon, Indonesia

International audienceThe concentrations of eight elements (Cr, Cu, Fe, Mn, Ni, Ti, V, and Zn) in surface sediments from Segara Anakan Nature Reserve (SARN), Indonesia, were determined using inductively coupled plasma-atomic emission spectroscopy following microwave-assisted acid digestion. In general, the heavy metal concentrations of the sediments were found to decrease in the sequence Fe>Ti>Mn>Zn>V>Cu>Cr>Ni. Sediment pollution assessment was carried out using a pollution status index contamination factor, pollution load index, geoaccumulation index, and enrichment factor as well as by comparing the measured values with two sediment quality guidelines, i.e., threshold effect level and probable effect level. The evaluation showed that in the refinery site stations, Cr, Ni, and Zn concentrations found in the SANR sediments may cause the adverse effect to occur over a wider range of organisms and can contribute to a more serious harmful effect