Tricyclic dihydropyrimidine-based multifunctional organic nanoparticles for detection of Ag (I) ions and spermidine: Real-Time application

- Biginelli-based organic nanoparticle sensor, N1 was developed using reprecipitation technique.
- N1 served as a primary sensor for Ag (I) ions while N1-Ag(I) complex acted as a secondary sensor for spermidine.
- Real sample analysis for Ag (I) in river water and spermidine in urine samples exhibited practical utility.
- N1-Ag(I) complex coated silica strips were developed for on-site recognition of spermidine.

In the present report a dihydropyrimidine-based Biginelli compound 1 was engineered into stable organic nanoparticles via reprecipitation method. The organic nanoparticles, N1 acted as an efficient fluorescent nanosensor for selective detection of Ag (I) ions via fluorescence quenching with a detection limit of 7.9 nM. Furthermore, successful detection of spermidine (an important biogenic amine) was realized through an indirect metal ion mediated approach where the quenched fluorescence of complex, C was recovered with a red-shift on addition of spermidine. The lowest detection limit for spermidine was found to be 3.2 nM. The nanosensor found applicability in a wide pH range from 3 to 12, which is appropriate for evaluation in environmental and physiological conditions. The selectivity for Ag (I) ions and spermidine was further confirmed with competitive binding studies which demonstrated no interference from other analytes. Moreover, real sample analysis established the practical applicability of the developed probes. The proposed strategy provides a facile, non-invasive, sensitive and economic platform for the estimation of Ag (I) ions in environmental samples (river water) and spermidine in biological samples (urine).

109