DPA Detection Research Articles

Ratiometric fluorescent detection of biomakers for biological warfare agents with carbon dots chelated europium-based nanoscale coordination polymers

A ratiometric fluorescent nanosensor for biological warfare agent 2,6-pyridinedicarboxylic acid (DPA) detection is developed with carbon dots (CDs)@europium-based nanoscale coordination polymers (Eu-NCPs). The abundant hydroxyl and carboxyl groups of CDs are served as starting points for the spontaneous self-assembly of europium ion (Eu3+) and 5′-guanosine monophosphate disodium (GMP) on the surface of CDs to form CDs@Eu/GMP nanocomposites. The obtained nanosensor exhibits the characteristic emission of CDs and weak emission of Eu3+. The Eu/GMP NCPs are served as the DPA recognition sites. The fluorescence of CDs remains constant as a reference, while the fluorescence of Eu/GMP NCPs is enhanced upon binding with DPA, resulting in ratiometric fluorescent response toward DPA. This ratiometric nanosensor exhibits good selectivity toward DPA detection. The ratio of F615/F469 linearly increases with the increasing of DPA concentration in the range of 25nM–5.0μM with a detection limit as low as 5.1nM. Additionally, the nanosensor is successfully applied for the determination of DPA in the real serum samples.

Lanthanide-functionalized silver nanoparticles for detection of an anthrax biomarker and test paper fabrication

It is highly desirable to develop a simple and sensitive analytical method for detection of anthrax biomarker (dipicolinic acid, DPA) because of its dangerous nature. In this work, we developed a fluorescent sensor for DPA detection based on terbium ion-functionalized silver nanoparticles with an average size of 6.7 nm (AgNPs–Tb3+). The fluorescent intensity of Tb–DPA complex on the surface of AgNPs was two times higher than that of Tb–DPA complex alone in a solution phase due to the metal-enhanced fluorescence (MEF) effect of AgNPs. The proposed fluorescent sensor exhibits excellent selectivity and high sensitivity for DPA. Importantly, a test paper for DPA detection was fabricated for the first time by the integration of AgNPs–Tb3+ onto the nitrocellulose membrane. Owing to the MEF effect of AgNPs, the lowest detectable concentration of the test paper-integrated AgNPs–Tb3+ for DPA by naked eyes is 10 times lower than that of the test paper-integrated Tb3+ alone. We believe that the presented strategy may open up new avenues to the development of portable and robust-sensing platforms based on functional hybrid materials.

Potentiometric sensor for dipicolinic acid

A potentiometric chemosensor for selective determination of dipicolinic acid (2,6-pyridinedicarboxylic acid, DPA) was developed based on the surface imprinting technique coupled with a nanoscale transducer: an indium tin oxide (ITO)-coated glass plate. The sensor fabrication conditions, optimal recognition condition, as well as selectivity, sensitivity, and stability of the DPA sensor have been investigated. The DPA sensor could recognize DPA from 3,5-pyridinedicarboxylic acid. Potentiometric measurements demonstrated selective detection of DPA in a concentration range of 1.5 × 10 −6 to 0.0194 M. The response time of DPA sensor for 4 × 10 −4 M DPA was 25 s. The potentiometric response of the DPA sensor to DPA is at 90% of its initial magnitude after 550 times measurement. The viability of such a modified ITO electrode in the presence of other inorganic, organic, and biological materials was probed.