8 research outputs found
Systemic varicella-zoster virus infection in two critically ill patients in an intensive care unit
STUDY OF THE NEAR INFRARED-MEDIATED HEATING OF DISPERSIONS OF PROTEIN-COATED PRISTINE AND CARBOXYLATED SINGLE-WALLED CARBON NANOTUBES
Use of Gel Electrophoresis and Raman Spectroscopy to Characterize the Effect of the Electronic Structure of Single-Walled Carbon Nanotubes on Cellular Uptake
Surface-Chemistry Effect on Cellular Response of Luminescent Plasmonic Silver Nanoparticles
Two-color spectroscopy of UV excited ssDNA complex with a single-wall nanotube photoluminescence probe: Fast relaxation by nucleobase autoionization mechanism
DNA autoionization is a fundamental process wherein ultraviolet (UV)-photoexcited nucleobases dissipate energy by charge transfer to the environment without undergoing chemical damage. Here, single-wall carbon nanotubes (SWNT) are explored as a photoluminescent reporter for the study of the mechanism and rates of DNA autoionization. Two-color photoluminescence spectroscopy allows separate photoexcitation of the DNA and the SWNTs in the UV and visible range, respectively. A strong SWNT photoluminescence quenching is observed when the UV pump is resonant with the DNA absorption, consistent with charge transfer from the excited states of the DNA to the SWNT. Semiempirical calculations of the DNA-SWNT electronic structure, combined with a Green’s function theory for charge transfer, show a 20 fs autoionization rate, dominated by hole transfer. Rate-equation analysis of the spectroscopy data confirms that the quenching rate is limited by thermalization of the free charge carriers transferred to the nanotube reservoir. This approach has great potential for monitoring DNA excitation, autoionization, and chemical damage, both in vivo and in vitro. [Figure not available: see fulltext.