Pyrene-labeled DNA probes for homogeneous detection of complementary DNA sequences: poly(C) model system

Area of Science:

• Molecular Biology
• Biochemistry
• Analytical Chemistry

Background:

• DNA and RNA probes are crucial for disease detection but current methods are complex.
• Homogeneous assays, which avoid probe separation, are desirable for simplifying molecular diagnostics.

Purpose of the Study:

• To investigate pyrene as a fluorescent label for DNA/RNA probes in homogeneous assays.
• To determine if pyrene's fluorescence properties change upon hybridization with target sequences.

Main Methods:

• Synthesized pyrene-labeled poly(C) as a model probe.
• Used poly(I) as the target sequence in a model system.
• Measured fluorescence emission spectra and lifetimes of pyrene-poly(C) before and after hybridization with poly(I).

Main Results:

• Hybridization of pyrene-poly(C) with poly(I) caused a 4-fold decrease in fluorescence intensity and a spectral shift.
• The average fluorescence lifetime of pyrene decreased from 10.78 ns to 4 ns upon hybridization.
• These fluorescence changes were observed in various chemical environments, including high salt concentrations.

Conclusions:

• Pyrene is a suitable fluorescent label for developing homogeneous DNA/RNA probe assays.
• The observed fluorescence changes are primarily due to alterations in fluorescence lifetime (efficiency), likely caused by a more hydrophilic environment upon hybridization.
• This pyrene-based approach allows for direct detection of target sequences without separating free and bound probes.