Dimethyl-pepep: a DNA probe in two-photon excitation cellular imaging.
Dimethyl-pepep (D-pepep), a newly developed and very efficient two-photon absorber, has been tested here for two-photon excitation (TPE) cellular imaging. The spectral characteristics of the dye following one-photon excitation (OPE) and TPE (excitation and emission spectra, fluorescence lifetime, molecular brightness, saturation intensity) are reported. In vitro interaction studies with biomolecules show that dimethyl-pepep has a large affinity for DNA. A comparison with a widely used DNA stainer, 4-6-diamidino-2-phenylindole (DAPI) bound to DNA shows that the D-pepep brightness is one order of magnitude higher than that of DAPI, making this dye suitable for microscopy and imaging applications. TPE images taken from double-stained yeast Saccharomyces cerevisiae cells have revealed that D-pepep localizes mainly in the nucleus, similarly to DAPI, and in mitochondria, although to a minor extent. Preliminary tests have shown that the dye cellular toxicity is negligible.
Abbotto
Alessandro
A
Dipartimento di Scienza dei Materiali and INSTM, Università di Milano Bicocca, Italy.
Baldini
Giancarlo
G
Beverina
Luca
L
Chirico
Giuseppe
G
Collini
Maddalena
M
D'Alfonso
Laura
L
Diaspro
Alberto
A
Magrassi
Raffaella
R
Nardo
Luca
L
Pagani
Giorgio A
GA
D004247:DNA / Q000737:chemistry*; D015342:DNA Probes; D005456:Fluorescent Dyes / Q000737:chemistry; D007211:Indoles / Q000737:chemistry; D017785:Photons; D011726:Pyridinium Compounds / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000378:metabolism; D013050:Spectrometry, Fluorescence
C503166:1-methyl-2,5-bis(2-(1-methylpyridinium-4-yl)ethenyl)pyrrole; D015342:DNA Probes; D005456:Fluorescent Dyes; D007211:Indoles; D011726:Pyridinium Compounds; D011758:Pyrroles; C007293:DAPI; D004247:DNA