Journal of Fluorescence

, Volume 26, Issue 2, pp 617–629 | Cite as

Synthesis and Identification of FITC-Insulin Conjugates Produced Using Human Insulin and Insulin Analogues for Biomedical Applications

  • Dolly Jacob
  • M. Joan Taylor
  • Paul Tomlins
  • Tarsem S. SahotaEmail author


Human insulin was fluorescently labelled with fluorescein isothiocyanate (FITC) and the conjugate species produced were identified using high performance liquid chromatography and electrospray mass spectroscopy. Mono-labelled FITC-insulin conjugate (A1 or B1) was successfully produced using human insulin at short reaction times (up to 5 h) however the product always contained some unlabelled native human insulin. As the reaction time was increased over 45 h, no unlabelled native human insulin was present and more di-labelled FITC-insulin conjugate (A1B1) was produced than mono-labelled conjugate with the appearance of tri-labelled conjugate (A1B1B29) after 20 h reaction time. The quantities switch from mono-labelled to di-labelled FITC-insulin conjugate between reaction times 9 and 20 h. In the presence of phenol or m-cresol, there appears to be a 10 % decrease in the amount of mono-labelled conjugate and an increase in di-labelled conjugate produced at lower reaction times. Clinically used insulin analogues present in commercially available preparations were successfully fluorescently labelled for future biomedical applications.


Insulin Fluorescent labelling FITC-insulin HPLC  Mono-labelled 



We thank EPSRC National Mass Spectrometry Facility, Swansea University for their help with FITC-insulin analysis. D Jacob would like to acknowledge the research studentship provided by De Montfort University.


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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • Dolly Jacob
    • 1
  • M. Joan Taylor
    • 1
  • Paul Tomlins
    • 1
  • Tarsem S. Sahota
    • 1
    Email author
  1. 1.Leicester School of Pharmacy, Faculty of Health and Life SciencesDe Montfort UniversityLeicesterUK

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