Fluorescent imprinted polymers for detection of explosive nitro-aromatic compounds

摘要

Molecular recognition is an important aspect of any biosensor system. Due to increased stability in a variety of environmental conditions, molecular imprinted polymer (MIP) technology is an attractive alternative to biological-based recognition. This is particularly true in the case of improvised explosive device detection, in which the sensor must be capable of detecting trace amounts of airborne nitroaromatic compounds. In an effort to create a sensor for detection of explosive devices via nitroaromatic vapor, MIPs have been deployed as a molecular recognition tool in a fluorescence-based optical biosensor. These devices are easily scalable to a very small size, and are also robust and durable. To achieve such a sensor scheme, polymer microparticles synthesized using methacrylic acid monomer and imprinted with a 2,4-dinitrotoluene (DNT) template were fabricated. These microparticles were then conjugated with green CdSe/ZnS quantum dots, creating fluorescent MIP microparticles. When exposed to the DNT template, rebinding occurred between the DNT and the imprinted sites of the MIP microparticles. This brings the nitroaromatic DNT into close proximity to the quantum dots, allowing the DNT to accept electrons from the fluorescent species, thereby quenching the fluorescence of the quantum dot. Results indicate that this novel method for synthesizing fluorescent MIPs and their integration into an optical biosensor produced observable fluorescence quenching upon exposure to DNT.