Elba Mauriz

Determination of environmental organic pollutants with a portable optical immunosensor

A portable surface plasmon resonance (SPR) optical biosensor device is described as a direct immunosensing system to determine organic pollutants in natural water samples. Monitoring of organochlorine (DDT), organophosphorus (chlorpyrifos) and carbamate (carbaryl) compounds within the concentration levels stipulated by the European legislation, can be accomplished using this immunosensor. The lowest limit of detection (LOD) was obtained for DDT, at 20 ng L(-1), whilst 50 ng L(-1) and 0.9 microg L(-1), were achieved for chlorpyrifos and carbaryl, respectively. Matrix effects were evaluated for the carbaryl immunoassay in different water types with detection limits within the range of carbaryl standard curves in distilled water (0.9-1.4 microg L(-1)). The covalent immobilization of the analyte derivative through an alkanethiol self-assembled monolayer (SAM) allowed the reusability of the sensor surface during more than 250 regeneration cycles. The quality of the regeneration was proved over a 1-month period of continuous working. The analysis time for a complete assay cycle, including regeneration, comprises 24 min. Our portable SPR-sensor system is already a market product, commercialized by the company SENSIA, SL. The size and electronic configuration of the device allow its portability and utilization on real contaminated locations.

OPTICAL BIOSENSOR DEVICES AS EARLY DETECTORS OF BIOLOGICAL AND CHEMICAL WARFARE AGENTS

The present article reviews three different optical biosensing mechanisms that can be implemented in a multibiosensor technology platform: surface plasmon resonance, magnetooptical surface plasmon resonance and optoelectronic biosensing (evanescent wave detection) using integrated Mach-Zehnder interferometer devices. In the last case, the use of standard silicon microelectronics technology opens the possibility for integration of optical, fluidics based and electrical functions within a single optical sensing circuit leading to a complete lab-on-a-chip design solution. All three mechanisms can be efficiently used as an early warning system for biological and/or chemical warfare.