Magno, Luís M.
Magno, Luís M.
Magno, Luís M.
Now showing 1 - 4 of 4
- PublicationLong-lived excited states in i-motif DNA studied by picosecond time-resolved IR spectroscopy(Royal Society of Chemistry, 2014-03-21)
; ; ; ; ;The transient IR absorption spectrum for UV-excited i-motif DNA is reported for the first time and found to possess complex dynamics pointing to multiple decay processes, including possible charge transfer between packed hemi-protonated C bases. 184Scopus© Citations 22
- PublicationPhotophysical studies of CdTe quantum dots in the presence of a zinc cationic porphyrin(RSC Publishing, 2012-09-24)
; ; ; ; ; ; ; ; ;The photophysical properties of 2.3 nm thioglycolic acid (TGA) coated CdTe quantum dots (QDs) prepared by a reflux method have been studied in the presence of cationic meso-tetrakis(4-N-methylpyridyl) zinc porphyrin (ZnTMPyP4). Addition of the CdTe QDs to the porphyrin in H2O results in a marked red-shift and hypochromism in the porphyrin absorption spectrum, indicative of a non-covalent binding interaction with the QD surface. Only low equivalents of the quantum dot were required for complete quenching of the porphyrin fluorescence revealing that one quantum dot may quench more than one porphyrin. Similarly addition of porphyrin to the quantum dot provided evidence for very efficient quenching of the CdTe photoluminescence, suggesting the formation of CdTe'porphyrin aggregates. Definitive evidence for such aggregates was gathered using small angle X-ray spectroscopy (SAXS). Ultrafast transient absorption data are consistent with very rapid photoinduced electron transfer (1.3 ps) and the resultant formation of a long-lived porphyrin species. 450Scopus© Citations 25
- PublicationIncandescent Porous Carbon Microspheres to Light up Cells: Solution Phenomena and Cellular Uptake(RSC Publishing, 2012)
; ; ; ; ; ; ;Carbon based materials are attractive for biological applications because of their excellent biocompatibility profile. Porous carbons with high specific surface area are particularly interesting because it is possible in principle to leverage their properties to deliver high drug payloads. In this work, porous carbon microspheres with high specific surface area were prepared and studied in solution and in cells. Raman optical tweezer trapping of microspheres, excited by 532 nm, results in graphitization and incandescence in solvents that display poor heat conduction. Fluorescence confocal microscopy imaging was used to demonstrate the uptake of fluorescently labelled microspheres by cells and the ability to leverage their optical absorptivity in order to cause carbon graphitization and cell death. 445Scopus© Citations 30
- PublicationUltrafast IR spectroscopy of polymeric cytosine nucleic acids reveal the long-lived species is due to a localised state(RSC Publishing, 2012-02-22)
; ; ; ; ; ; ; ; ;The decay pathways of UV-excited cytosine polymers are investigated using picosecond time-resolved infrared spectroscopy. Similar yields of a non-emissive (1)nÏ * state are found in the single-stranded dC(30) polymer as in the dCMP monomer, but with a longer lifetime in the polymer (80 ps vs. 39 ps). A longer lifetime is also found in the d(CpC) dinucleotide. No evidence of excimer states is observed, suggesting that localised (1)nÏ * excited states are the most significant intermediates present on the picosecond timescale. 334Scopus© Citations 11