Anna Maria Fiorello

A surface plasmon resonance-based biochip to reveal traces of ephedrine

Ephedrine is a crucial chemical precursor for clandestinely produced amphetamine and its related drugs. Also, ephedrine is intentionally added to illegal preparations of methamphetamine or amphetamine because it is cheaper than the other two drugs. Consequently there is a pressing need to prevent the entry of ephedrine into commerce. Therefore the challenge calls for non-invasive techniques that provide data on the presence of ephedrine even in trace amounts. In this paper we describe the synthesis of a new ephedrine derivative with a carbon linker featuring an amino reactive group, and its conjugation to the glutamine binding protein (GlnBP) from E. coli as a carrier protein for the production of polyclonal antibodies against ephedrine. Proof-of-principle results of an efficient SPR-based indirect competitive immunoassay for the detection and quantification of ephedrine are presented. The detection limit of the assay was about 33 ng ml−1.

Cross-Bar Design of Nano-Vacuum Triode for High-Frequency Applications

In this letter, a new nano-vacuum triode based on carbon nanotubes (CNTs) has been designed. The use of CNTs as emitters with their extremely high aspect ratio and their characteristics to be patterned in specific emitting areas allowed the realization of a cross-bar geometry for which the transconductance is maximized and the grid-cathode capacitance is reduced. This allowed us to achieve a device cutoff frequency of 156 GHz, which is well beyond the state of the art.

Determination of benzyl methyl ketone – a commonly used precursor in amphetamine manufacture

1-Phenyl-2-propanone (P-2-P), also known as benzyl methyl ketone (BMK), is a colorless or slightly yellowish liquid. It presents a density similar to that of water as well as a pleasant scent. Even if there are few legitimate uses of BMK such as in the production of the pharmaceutical drug propyl-hexedrine, most frequently BMK is used as an illicit compound for the illegal manufacture of amphetamine. Actually, BMK is identified by classical methods such as gas chromatography, NMR or HPLC. These methods are costly, time-consuming and require the presence of trained operators. It appears obvious that there is an urgent need to develop a new easy and fast method that allows us to detect the presence of traces of BMK. In this work, a new chemically synthesized BMK derivative covalently attached to an immunological carrier was used for producing antibodies against the BMK molecules. A fluorescence polarization-based bioassay was developed by using the produced anti-BMK antibodies and the BMK derivative. The assay exhibits interesting analytical performances with a limit of detection of less than 100 nM and an almost linear response up to 600 nM. Interestingly, the proposed assay could be performed using a customizable portable instrumentation and could be used by non-instructed personnel at custom borders and checkpoints or for quick spot-checks.

Preparation and Thermal Characterization of Carbon Nanotubes-Based Composites for Applications in Electronics Packaging

The thermal resistance of nanocomposite layers formed by Single Wall Carbon Nanotubes (SWCNT) dispersed in epoxy resins has been measured under conditions similar to the ones used to dissipate heat in microelectronic devices. The variation of thermal conductivity as a function of concentration of SWCNT is reported and discussed with reference to the dispersion state of SWCNT in the layers.

A feature selection strategy for the analysis of spectra from a photoacoustic sensing system

In the frame of the EU project CUSTOM, a new sensor system for the detection of drug precursors in gaseous samples is being developed, which also includes an External Cavity-Quantum Cascade Laser Photo Acoustic Sensor (ECQCLPAS). In order to define the characteristics of the laser source, the optimal wavenumbers within the most effective 200 cm-1 range in the mid-infrared region must be identified, in order to lead to optimal detection of the drug precursor molecules in presence of interfering species and of variable composition of the surrounding atmosphere. To this aim, based on simulations made with FT-IR spectra taken from literature, a complex multivariate analysis strategy has been developed to select the optimal wavenumbers. Firstly, the synergistic use of Experimental Design and of Signal Processing techniques led to a dataset of 5000 simulated spectra of mixtures of 33 different gases (including the 4 target molecules). After a preselection, devoted to disregard noisy regions due to small interfering molecules, the simulated mixtures were then used to select the optimal wavenumber range, by maximizing the classification efficiency, as estimated by Partial Least Squares – Discriminant Analysis. A moving window 200 cm-1 wide was used for this purpose. Finally, the optimal wavenumber values were identified within the selected range, using a feature selection approach based on Genetic Algorithms and on resampling. The work made will be relatively easily turned to the spectra actually recorded with the newly developed EC-QCLPAS instrument. Furthermore, the proposed approach allows progressive adaptation of the spectral dataset to real situations, even accounting for specific, different environments.

Towards a THz backward wave amplifier in European OPTHER project

Within the EC funded international project OPTHER (OPtically Driven TeraHertz AmplifiERs) a considerable technological effort is being undertaken, in terms of technological development, THz device design and integration. The ultimate goal is to develop a miniaturised THz amplifier based on vacuum-tube principles The main target specifications of the OPTHER amplifier are the following: - Operating frequency: in the band 0.3 to 2 THz - Output power: > 10 mW ( 10 dBm ) - Gain: 10 to 20 dB. The project is in the middle of its duration. Design and simulations have shown that these targets can be met with a proper device configuration and careful optimization of the different parts of the amplifier. Two parallel schemes will be employed for amplifier realisation: THz Drive Signal Amplifier and Optically Modulated Beam THz Amplifier.

Nanotechnology RADAR thermal management

Active phased array antennas in state of art radars, adopt many high power amplifiers. High power transmit-receive modules are assembled in dense electronic environments and they have to cope with severe environmental operative condition. Radar state of art systemic signal processing requires growing and enormous power calculation in order to obtain unprecedented hard real-time performances as well as implementing adaptive knowledge based algorithms. Unfortunately the present steady growth of the micro-processors performance are reaching a saturation point due to the approaching limit of miniaturizations. Present and future active phased array antennas and signal processors have large and increasing heat dissipation problems. Nanotechnologies are emerging as enabling technologies that will provide a revolution in the sectors of sensors and radar systems. These innovative technologies could enable new solutions and improve weight, size, speed, power consumption, efficiency, and so on. In addition, the nanotechnologies could solve the increasing heat dissipation problems by adopting carbon nanotubes CNT ropes or arrays for thermal management and interconnection.

A Feature Selection Strategy for the Development of a New Drug Sensing System

In order to efficiently detect four drug precursor molecules in presence of interfering species and background air, using a EC-QCLPAS sensor operating in the mid-infrared region, a complex strategy of spectral response simulation has been developed. In this context, spectra of gases from literature databases have been collected, denoised by means of the Wavelet Transform and mixed together according to a concentration matrix, which was specifically designed to represent a comprehensive combination of possible realistic cases. To scale database spectra to the appropriate concentration levels, an ad-hoc algorithm based on a sigmoidal transfer function has been used. In this way the baseline shape and intensity is preserved. Afterwards, a preliminary wavelength selection has been carried out to exclude noisy regions. The optimal range has finally been defined by maximizing the classification efficiency for all the target gases by means of Partial Least Squares-Discriminant Analysis.

Toward a Compact Instrument for Detecting Drug Precursors in Different Environments

Law enforcement agencies world-wide are keenly aware that chemical control is a crucial element to monitor the manufacture and distribution of illegal narcotics and synthetic substances. For this purpose components able to perform chemical identifications in contexts such as custom offices are needed, where inspection of trucks, cars, containers, as well as people and baggage, is required.

A new optical method for a fast and simple detection of ephedrine

In this work we describe the synthesis of a new ephedrine derivative with a carbon linker featuring an amino reactive group, and its conjugation to the glutamine binding protein (GlnBP) from E. coli as a carrier protein for the production of polyclonal antibodies in rabbits against ephedrine. Proof-of-principle results that an efficient SPR-based indirect competitive immunoassay for the detection and quantification of ephedrine are presented. The detection limit of this assay was found to be about 33ng/ml.