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

Sangram L. Raut, Ryan Rich, Rafal Fudala, R. Kokate, J. D. Kimball, Julian Borejdo, Jamboor K. Vishwanatha, Zygmunt Gryczynski, Ignacy Gryczynski

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Although BSA Au clusters fluoresce in red region (λmax: 650nm), they are of limited use due to low fluorescence quantum yield (~6%). Here we report an enhanced fluorescence imaging application of fluorescent bio-nano probe BSA Au clusters using multipulse excitation scheme. Multipulse excitation takes advantage of long fluorescence lifetime (> 1μs) of BSA Au clusters and enhances its fluorescence intensity 15 times over short lived cellular auto-fluorescence. Moreover we have also shown that by using time gated detection strategy signal (fluorescence of BSA Au clusters) to noise (auto-fluorescence) ratio can be increased by 30 fold. Thereby with multipulse excitation long lifetime probes can be used to develop biochemical assays and perform optical imaging with zero background.

Original languageEnglish
Pages (from-to)1139-1144
Number of pages6
JournalCurrent Pharmaceutical Biotechnology
Issue number13
StatePublished - 1 Jan 2014



  • Autofluorescence
  • BSA au clusters
  • Long lifetime
  • Multipulse excitation
  • Signal to noise

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