Research
Designing Ionic Liquid Self Assembly, Structural and Dynamics Study: Time Resolve Fluorescence Spectroscopy:
We have design various ionic liquid containing self assemble structure like micelle, reverser micelle, microemulsion etc. The results show that nanostructure are mono dispersed and quite stable. This nanostructure was used as a template to synthesis silver nanoparticles. Time resolved fluorescence spectroscopy shows the dynamics of ionic liquid in comparison to bulk ionic liquids. From dynamics study we can calculate micro-viscosity of ionic liquid in nanoconfined media and made comparison with pure ionic liquids. The micro-viscosity of ionic liquid in confined media and dynamics of pure ionic liquids shows strong correlation.
Single Molecule Tracking and Dichroism Measurements: Single Molecule Fluorescence Microscopy:
We have directly recorded single molecule motions in the one-dimensional (1D) channels of nanostructured materials by single molecule tracking (SMT) methods. SMT methods afford unique advantages over other ensemble methods such as FCS, of SAXS in that 1D molecular motions can be directly visualized. While such methods are well known, our unique contributions include their use for quantitative assessment of channel organization. The results showed that the dye diffused within the micelle cores and that materials produced by flow alignment in microfluidic channels were extremely well ordered. In our most exciting work, we have since moved on to study single molecule orientational wobbling (i.e., confined orientational motions) within the surfactant-filled cylindrical pores of mesoporous silica. In these studies, we simultaneously record SMT data in two orthogonal polarizations. The dichroism data affords a highly quantitative measure of the degree to which the orientational motions of the molecules are confined within the pores. The results yield an in situ measure of the accessible cavity diameter with ~ 0.2 nm precision, much better than can presently be achieved by super-localization microscopy methods reported in the literature.
Development of Fluorescence Sensors for Detecting Metals Ion:
More recently, the toxic metal ions and biological molecular sensing and bioimaging applications have increasing attracted to attention of researchers. 1, 8-Naphthalimide (NI), Naphthalene diimide (NDI), Perylene bisimide (PBI) and its derivatives play a key role in fluorescent material and dye field. In addition, the special structure of NI, NDI and PBI endow them excellent properties, high electron affinity, good thermal stability and oxidation stability, this has led to their development and application receiving widespread attention. Naphthalimide, as the “simplest” molecule, has better water solubility than the other molecules such as NDI and PBI. Therefore, the study of naphthalimide derivatives has become a hot topic. Given the excellent photophysical properties and stability, 1,8 naphthalimide-based fluorescent probe has enormous potential for developing chemical sensors. However, using 1,8 naphthalimide-based fluorescent probe have not yet been fully developed for metal sensing. Therefore, it is necessary to design fluorescent probe for the various applications based on 1.8-naphthalimide and its derivatives. Our goals to design the chemosensors and materials applications of 1.8-naphthalimide research, including ion detection, molecular recognition, material preparation, bioimaging and other fields.
The NDI and PBI dyes are widely used sensors in organic media thanks to their high fluorescence quantum yields (QY), absorption and emission spectra, which can be easily tuned in the visible region from green to red and near-IR. Given the hydrophobic nature of these dyes and high QY, these can be used to detect bio-molecules present in complex self assemble structure. Perylene bisimide (PBI) is highly photo-stable and widely used as a single molecule probes in wide field microscopy imaging.
We are hoping for the development of more powerful fluorescent chemosensors for broad and exciting applications in the future.
