Yogesh Ner

White Luminescence from Multiple‐Dye‐Doped Electrospun DNA Nanofibers by Fluorescence Resonance Energy Transfer

A DNA spin-off: Electrospinning of DNA complexes gives nanofibers with a highly ordered morphology that allows homogeneous distribution of encapsulated multiple chromophores. The emission color can be controlled by suitable choice of the donor-acceptor pair and the doping ratio. Pure white-light emission from nanofibers is demonstrated (see picture).

Three dye energy transfer cascade within DNA thin films

An efficient cascade FRET was realized in solid state DNA-CTMA thin films using a three chromophore system without any covalent attachments. The extent of energy transfer from Cm102 to SRh was studied and found to improve eight-fold using the bridging dye Pm567.

Nanofiber alignment on a flexible substrate: hierarchical order from macro to nano.

A simplified approach to constructing a composite material comprised of aligned electrospun nanofibers onto a flexible substrate consisting of a microfilament yarn is presented. The metal-coated knit patterns of the microfilament yarn play the role of the parallel electrode, required for the alignment of electrospun nanofibers. Hybrid materials with knitted textile as a support material and aligned high-surface-area nanofibers could represent ideal materials for use in the filtration, optical, and biomedical industries.

Enhanced fluorescence in electrospun dye-doped DNA nanofibers

Nanoscale fibers and non-woven meshes composed of DNA complexed with a cationic surfactant (cetyltrimethylammonium chloride, or CTMA) have been fabricated through electrospinning. The DNA-CTMA complex can be electrospun far more easily than DNA alone. Incorporation of a hemicyanine chromophore resulted in materials that demonstrated amplified emission as compared to thin films of identical composition. The enhanced fluorescence resulted from both the fiber morphology (5-6-fold amplification) and specific interactions (groove-binding) between the chromophore and DNA (18-21-fold amplification). The mechanical properties of freestanding electrospun non-woven fiber meshes were evaluated, and revealed stress-induced alignment of DNA strands within the DNA-CTMA fibers. These fiber-based materials are easily processable into a variety of morphologies, and have promise for applications in molecular electronics, filtration, sensors, and the medical industry.

Stabilization of fluorophore in DNA thin films

The photostability of the nonlinear optical dye, Hemi-22, improves upon encapsulation in DNA thin films. The interactions of Hemi-22 with DNA, along with the intrinsic properties of DNA are responsible for these remarkable improvements in the photostability of the dye in comparison to the dye in a poly(methyl methacrylate) as a control.