BSA Au clusters as a probe for enhanced fluorescence detection using multipulse excitation scheme

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Optical Imaging

Background:

• Bovine serum albumin gold (BSA Au) clusters exhibit red fluorescence (λmax: 650 nm) but suffer from low quantum yield (~6%).
• Existing limitations hinder their application in sensitive bio-imaging and biochemical assays.

Purpose of the Study:

• To enhance the fluorescence imaging capabilities of BSA Au clusters.
• To overcome low quantum yield and auto-fluorescence interference using novel excitation strategies.

Main Methods:

• Employing a multipulse excitation scheme tailored for the long fluorescence lifetime (> 1 µs) of BSA Au clusters.
• Utilizing time-gated detection to differentiate probe fluorescence from cellular auto-fluorescence.

Main Results:

• Achieved a 15-fold enhancement in BSA Au cluster fluorescence intensity compared to auto-fluorescence.
• Increased the signal-to-noise ratio by 30-fold using time-gated detection.
• Demonstrated the potential for background-free optical imaging.

Conclusions:

• Multipulse excitation effectively boosts the fluorescence signal of long-lifetime probes like BSA Au clusters.
• Time-gated detection significantly improves signal-to-noise ratio, enabling sensitive bio-imaging.
• This approach opens avenues for developing advanced biochemical assays and zero-background optical imaging techniques.