(Invited) Optics of Nanotubes, DNA and Rare Earth Ions: Towards Composite Material for Biosensing
Authors: Rotkin Slava V. 
Published: February 2020

Potential attractiveness of rare earth ions (REI) for bio-sensing applications, such as Fluorescence/Foerster Resonance Energy Transfer (FRET) and simple photoluminescence (PL) imaging[i] motivated us to explore optical properties[ii] of complexes of several REI with single-wall nanotubes (SWNT) wrapped by ssDNA. REI/DNA/SWNT materials happen to be rich in basic physics effects, ranging from FRET which can be used for quantitative analysis of the structure of the complexes[iii] to non-trivial time dependence of the PL in a silica hydrogel matrix[iv]. The latter material provides an example of a bio-mimetic crowded environment, where SWNTs make a structural scaffold. When bonded to SWNTs, multivalent ions may induce changes in the nanotube bandstructure, including localization of excitons on a single ion defect site[v]. The ssDNA, ionized in solution, in these complexes not only plays the role of a dispersive element, maintaining SWNTs in water suspension due to strong electrostatic repulsive forces. ssDNA may also lead to Manning condensation of the multivalent ions on the SWNT surface due to the forces of the same strength but attractive type. In other cases, the ssDNA becomes an active element of the optical material[vi], interfering with SWNT chirality[vii] or creating a new photo-induced exciton non-radiative recombination channel[viii]. In this talk I will present recent experimental results along with theoretical interpretation of various phenomena, embracing optics, chemistry, physics and material science of these composite objects.

Acknowledgement: This work was supported by: NSF ECCS-1202398

References

[i] Slava V. Rotkin, “Electronic properties of DNA/SWNT hybrids: From charge separation to optical sensing”, in Handbook on Carbon Nano Materials, Vol. 2, ed. F DiSouza, K Kadish. World Scientific Publishing, Inc., Ch. 23 (2011).

[ii] Tetyana Ignatova, Andrei M. Nemilentsau, and Slava V. Rotkin, “Near-field optics of SWNTs and FRET in their nanoscale complexes”, in Handbook on Carbon Nano Materials, Vol. 4:, ed. F DiSouza, K Kadish. World Scientific Publishing, Inc., Ch. 8 (2012).

[iii] Tetyana Ignatova, Hikmat Najafov, Aleksandr Ryasnyanskiy, Ivan Biaggio, Ming Zheng and Slava V. Rotkin, “Significant FRET Between SWNT/DNA and Rare Earth Ions: A Signature of Their Spatial Correlations”, ACS Nano, 5 (7), 6052-6059 (2011). DOI: 10.1021/nn201911b

[iv] Tetyana Ignatova, Michael Blades, Juan G. Duque, Stephen K. Doorn, Ivan Biaggio, and Slava V. Rotkin, “Formation and Dynamics of "Waterproof" Photoluminescent Complexes of Rare Earth Ions in Crowded Environment”, Physical Chemistry Chemical Physics, 16 (48), 26715 - 26721 (2014). DOI: 10.1039/C4CP04342A

[v] Benjamin O. Tayo, and Slava V. Rotkin, “Charge impurity as a localization center for singlet excitons in single-wall nanotubes”, Phys. Rev. B 86, 125431 (2012). DOI: 10.1103/PhysRevB.86.125431

[vi] Slava V. Rotkin, “Electronic Properties of Nonideal Nanotube Materials: Helical Symmetry Breaking in DNA Hybrids”, Annual Review of Physical Chemistry Vol. 61, pp. 241-261 (2010). doi:10.1146/annurev.physchem.012809.103304

[vii] Stacy E. Snyder, and Slava V. Rotkin, “Optical Identification of a DNA-Wrapped Carbon Nanotube: Signs of Helically Broken Symmetry", Small, vol. 4 (9), 1284-1286, (2008).

[viii] Tetyana Ignatova, Michael Blades, Jeffrey Fagan, Ming Zheng and Slava V. Rotkin, [unpublished].