Fluorescent polyacrylamide nanoparticles for naproxen recognition

Complete text of publication follows. The present communication is focused on the synthesis of polymer nanoparticles (NPs) capable of binding to specific biomolecules such as non-steroidal anti-inflammatory drugs (NSAIDs). Within this important group we selected Naproxen, one of the 2-arylpropionic acids (profens), due to its use for the reduction of moderate to severe. We have developed inexpensive and selective nanoparticles under mild conditions of inverse microemulsion polymerization using aqueous acrylamide as monomer and N-N'methylenebisacrylamide as cross-linker, employing the surfactants polyoxyethylene-4-lauryl ether (BrijR30) and sodium bis(2-ethylhexyl)- sulfosuccinate in hexane. We incorporated into the nanoparticles a selective fluorescent monomer, (E)-4-(4-(dimethylamino)styryl)-1-(4(methacryloyloxymethyl)benzyl) pyridinium chloride (mDMASP) which shows, inside the nanoparticles, a broad absorbance at around 460 nm and fluorescence emission at around 590 nm when suspended in phosphate buffer of pH 7.2. The acrylamide nanoparticles exhibited a diameter in the range of 50-100 nm. The analyte recognition is based on an increase in fluorescence at 590 nm upon addition of different concentrations of Naproxen. In order to evaluate the selectivity of the nanoparticles for the intended application to water analysis, a systematic study was conducted on the effect produced by common species that can interfere in the determination of Naproxen, demonstrating the selectivity of this method. Thus, we propose a new method for the determination of Naproxen that can be used for different analytical applications, considering the simplicity of the procedure. We thankfully acknowledge the financial support from the EU Transfer of Knowledge project 'Sensor Nanoparticles for Ions and Biomolecules' (MTKD-CT-2005-029554) and the EU Research Training Network 'Nanomaterials for Application in Sensors, Catalysis and Emerging technologies' (MRTN-CT-2006-033873).