5 research outputs found
Amplified Fluorescence Quenching of Lucigenin Self-Assembled inside Silica/Chitosan Nanoparticles by Cl<sup>–</sup>
Fluorescence
sensing
of an analyte based on the fluorophore collective
effect is a reliable, sensitive sensing approach. Many ultralow targets
can be detected on the basis of the high sensitivity and signal amplification
of the fluorescence sensing system. However, the complicated synthesis
procedures, harsh conditions required to design and control the fluorescence
molecular probes and conjugated chain length, and the higher cost
of synthesis are still challenges. To address these issues, we developed
a simple, rapid, and sensitive collective effect based fluorescence
sensing platform. In this sensing platform, the fluorophore unit was
self-assembled on the wall of the nanopores of the porous structural
silica/chitosan nanoparticles (SCNPs) on the basis of the electrostatic
interaction and supermolecular interaction between the fluorophores
and SiO<sup>–</sup> groups and chitosan. Since these self-assembled
fluorophores are close enough to communicate with each other on the
basis of the space confinement effect of the pore size, many fluorophore
units could interact with a single analyte and produce an amplified
fluorescence sensing ability. Chloride ion, an important anion in
biological fluids, and lucigenin, a typical fluorescent dye, were
used as a model to confirm the proof-of-concept strategy. Our results
showed that, compared to free-state lucigenin in solution, the assembled-state
lucigenin in SCNPs presented an about 10-fold increase in its Stern–Volmer
constant when the concentration of Cl<sup>–</sup> was lower
than 10 mM, and this fluorescence nanosensor was also successfully
used to sense the chloride ion in living cells
Magnetic, Fluorescence and Transition Metal Ion Response Properties of 2,6-Diaminopyridine Modified Silica-Coated Fe3O4 Nanoparticles
Multi-functional nanoparticles possessing magnetic, fluorescence and transition metal ion response properties were prepared and characterized. The particles have a core/shell structure that consists of silica-coated magnetic Fe3O4 and 2,6-diaminopyridine anchored on the silica surface via organic linker molecules. The resultant nanoparticles were found by transmission electron microscopy to be well-dispersed spherical particles with an average diameter of 10–12 nm. X-ray diffraction analysis suggested the existence of Fe3O4 and silica in/on the particle. Fourier transform infrared spectra revealed that 2,6-diaminopyridine molecules were successfully covalently bonded to the surface of magnetic composite nanoparticles. The prepared particles possessed an emission peak at 364 nm with an excitation wavelength of 307 nm and have a strong reversible response property for some transition metal ions such as Cu2+ and Zn2+. This new material holds considerable promise in selective magneto separation and optical determination applications