Gaganpreet Kaur

Selective recognition of lithium(I) ions using Biginelli based fluorescent organic nanoparticles in an aqueous medium

This study presents the fabrication of a Biginelli compound 1 into fluorescent organic nanoparticles (ONP) using a reprecipitation method. The fabricated ONP were characterized by TEM and DLS. Further, the ONP were found to be selective towards Li(I) ions with a “fluorescence turn-on” mechanism and exhibited no significant response to possibly interfering cations (Na+, K+, Mg2+ and Ca2+) in a competitive experiment. The limit of detection was calculated to be 122 nM. It is apparent from the pH titration that the current sensor is independent of any variation in pH. To get a better insight of spacial arrangement, the crystal structure of 1 was solved by X-ray crystallography. The progress in sensing of lithium ions by various types of sensors on different instruments has also been discussed briefly.

A Biginelli-based organic nanoprobe for simultaneous estimation of tyramine and 1,2-diaminopropane: application in real samples

The detrimental effects caused by the presence of biogenic amines in food samples render them an important parameter for evaluating food quality. In the current report, a facile fluorescent Biginelli based receptor 1 has been prepared through a multicomponent reaction between pyridine-2-carbaldehyde, methyl acetoacetate and 2-aminobenzimidazole in a single pot using a zinc perchlorate catalyst. Subsequently, the receptor 1 was processed to obtain aqueous phase organic nanoparticles, N1, which were characterized using DLS and TEM. Fluorescence spectroscopy studies in aqueous media revealed that the organic nanoparticles show interesting potential for Ag(I) recognition with a fluorescence “turn-off” mechanism. The resultant Ag–receptor complex, N1.Ag(I), was further found to bind with tyramine (limit of detection: 3.91 nM) and 1,2-diaminopropane (limit of detection: 4.21 nM) through unquenching of fluorescence.

Correlation of edge truncation with antibacterial activity of plate-like anisotropic silver nanoparticles

The effect of silver nanoparticle anisotropy on the antibacterial properties has been studied against Escherichia coli, Staphylococcus aureus, Bacillus, Vibrio cholerae, and Streptococcus pyogenes. Anisotropic silver nanoparticles have been synthesized by solvothermal process. The UV-visible absorption, X-ray diffraction, and TEM studies show the anisotropic nature of silver nanoparticles. The results demonstrate that the anisotropic silver nanoparticles undergo a shape-dependent interaction with the bacteria, and the nanoparticles with higher anisotropy exhibit the superior antibacterial activity. Silver nanoparticles with sharp edges and corners displayed the stronger biocidal action, in comparison to the anisotropic nanoparticles with round edges and corners. The sharpness of the corners has been quantified using degree of truncation method. The variation in degree of truncation and the antibacterial activity follows the same pattern.

Cobalt complexes of Biginelli derivatives as fluorescent probes for selective estimation and degradation of organophosphates in aqueous medium

The unregulated use of organophosphates (OPs) as pesticides and toxic chemical warfare agents demands their continuous monitoring from a human health perspective. This study describes a fluorescence turn-on sensing assay for the selective quantification of OPs in aqueous medium. Metal complexes of two different Biginelli derivatives were processed in water through a reprecipitation technique. The engineered self-assembly of the pyridyl-2-cobalt complex (L1·Co(II)) was employed to selectively detect malathion while the pyridyl-4-cobalt complex (L2·Co(II)) could estimate azamethiphos fluorimetrically up to a detection limit of 9.2 nM and 11 nM, respectively. Furthermore, the pesticide degradation ability of OPs was assessed using a 31P-NMR technique. This new paradigm expands the versatility of Biginelli derivatives as promising sensing platforms via metal complexation which may further be explored for estimation of analytes.