Electrostatic Interactions of Fluorescent Molecules with Dielectric Interfaces Studied by Total Internal Reflection Fluorescence Correlation Spectroscopy

• Electrostatic interactions between dielectric surfaces and different fluorophoresused in ultrasensitive fluorescence microscopy are investigated using objective-based TotalInternal Reflection Fluorescence Correlation Spectroscopy (TIR-FCS). The interfacialdynamics of cationic rhodamine 123 and rhodamine 6G, anionic/dianionic fluorescein,zwitterionic rhodamine 110 and neutral ATTO 488 are monitored at various ionic strengthsat physiological pH. As analyzed by means of the amplitude and time-evolution of theautocorrelation function, the fluorescent molecules experience electrostatic attraction orrepulsion at the glass surface depending on their charges. Influences of the electrostaticinteractions are also monitored through the triplet-state population and triplet relaxationtime, including the amount of detected fluorescence or the count-rate-per-moleculeparameter. These TIR-FCS results provide an increased understanding of how fluorophoresare influenced by the microenvironment of a glass surface, and show a promising approachfor characterizing electrostatic interactions at interfaces.

Ämnesord

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

Nyckelord

electrostatic interactions

fluorescent molecules

glass interfaces

Total Internal Reflection

Fluorescence Correlation Spectroscopy

Spectroscopy

Spektroskopi

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