Localization Study of Photostable Alexa 488 at Single Molecule Level.

Understanding the relationships between molecular organization and dynamics of a complex system is very important to understand the photophysical properties of such system. This paper focuses on a novel strategy based on single molecule spectroscopy and single molecule localization microscopy to elucidate the photostability and localization of a fluorophore molecule on a 2D biomembrane. Improvement of in-plane resolution of a signal in a nano-dimension within the diffraction limit has been discussed in a new way. And, how this better in-plane resolution information can be used for precise localization of a single molecule on a 2D system has also been discussed.

Real-time electro-diffusion method to discriminate carbon nanomaterials.

We report both the experimental and theoretical insights of differential electro-diffusion behavior of carbon nanomaterials (e.g. single wall, multiwall carbon nanotubes, and graphene). We thus discriminate one from the other in a soft gel system. The differential mobility of such material depends on their intrinsic properties, both extend and rate of migration bearing the discriminatory signature. The mobility analysis is made by a real time monitoring of the respective bands.

Chirality sensitive binding of tryptophan enantiomers with pristine single wall carbon nanotubes.

We report the differential binding nature of pristine single wall carbon nanotubes (SWNTs) with tryptophan enantiomers. The differential co-operative response between the pristine SWNTs (topologically chiral) and L- and D-tryptophan (geometrically chiral) provides the insight that geometrical chirality itself manifests with topological chirality in a complex way.

Reusable glucose sensing using carbon nanotube-based self-assembly.

Lipid functionalized single walled carbon nanotube-based self assembly forms a super-micellar structure. This assemblage has been exploited to trap glucose oxidase in a molecular cargo for glucose sensing. The advantage of such a molecular trap is that all components of this unique structure (both the trapping shell and the entrapped enzyme) are reusable and rechargeable. The unique feature of this sensing method lies in the solid state functionalization of single walled carbon nanotubes that facilitates liquid state immobilization of the enzyme. The method can be used for soft-immobilization (a new paradigm in enzyme immobilization) of enzymes with better thermostability that is imparted by the strong hydrophobic environment provided through encapsulation by the nanotubes.

Molecular discriminators using single wall carbon nanotubes.

The interaction between single wall carbon nanotubes (SWNTs) and amphiphilic molecules has been studied in a solid phase. SWNTs are allowed to interact with different amphiphilic probes (e.g. lipids) in a narrow capillary interface. Contact between strong hydrophobic and amphiphilic interfaces leads to a molecular restructuring of the lipids at the interface. The geometry of the diffusion front and the rate and the extent of diffusion of the interface are dependent on the structure of the lipid at the interface. Lecithin having a linear tail showed greater mobility of the interface as compared to a branched tail lipid like dipalmitoyl phosphatidylcholine, indicating the hydrophobic interaction between single wall carbon nanotube core and the hydrophobic tail of the lipid. Solid phase interactions between SWNT and lipids can thus become a very simple but efficient means of discriminating amphiphilic molecules in general and lipids in particular.