Millisecond fading and recovery phenomena in fluorescent biological objects

Area of Science:

• Biophysics
• Analytical Chemistry
• Cell Biology

Background:

• Fluorophores are crucial for biological imaging and diagnostics.
• Understanding fluorescence dynamics, especially rapid changes, is essential for accurate measurements.
• Existing techniques may be influenced by transient fluorescence behaviors.

Purpose of the Study:

• To investigate rapid cytofluorometric signals in the millisecond range.
• To identify and characterize a novel millisecond fluorescence fading phenomenon.
• To assess the implications of this phenomenon for fluorometric techniques.

Main Methods:

• Studied cytofluorometric signals from various fluorophores (Berberine sulphate, Acriflavine-Feulgen, Acridine orange, Fluorescein isothiocyanate-conjugated IgG).
• Recorded signals during millisecond illumination times using a storage oscilloscope.
• Examined fluorescence dynamics in stained biological samples (mast cell heparin, DNA) and in an antinuclear factor test.

Main Results:

• Observed a new millisecond fluorescence fading phenomenon with rapid recovery (approx. 10 ms duration).
• This phenomenon occurred in most studied fluorophores, excluding Fluorescein isothiocyanate-conjugated IgG.
• The phenomenon's presence varied with Acridine orange binding (present with DNA, absent with heparin).

Conclusions:

• The millisecond fading and recovery is a significant characteristic of certain fluorophores.
• This transient behavior impacts fluorometric measurement accuracy.
• The distinct occurrence of this phenomenon suggests its potential utility in developing advanced fluorescent microprobe studies.