Homogeneous insulin and C-Peptide sensors for rapid assessment of insulin and C-peptide secretion by the islets

Diabetes. 2010 Oct;59(10):2360-5. doi: 10.2337/db10-0088. Epub 2010 Jul 9.


Objective: Glucose-stimulated islet insulin or C-peptide secretion experiments are a fundamental tool for studying and assessing islet function. The goal of this work was to develop Ab-based fluorescent homogenous sensors that would allow rapid, inexpensive, near-instantaneous determinations of insulin and C-peptide levels in biological samples.

Research design and methods: Our approach was to use molecular pincer design (Heyduk et al., Anal Chem 2008;80:5152-5159) in which a pair of antibodies recognizing nonoverlapping epitopes of the target are modified with short fluorochrome-labeled complementary oligonucleotides and are used to generate a fluorescence energy transfer (FRET) signal in the presence of insulin or C-peptide.

Results: The sensors were capable of detecting insulin and C-peptide with high specificity and with picomolar concentration detection limits in times as short as 20 min. Insulin and C-peptide levels determined with the FRET sensors showed outstanding correlation with determinations performed under the same conditions with enzyme-linked immunosorbent assay. Most importantly, the sensors were capable of rapid and accurate determinations of insulin and C-peptide secreted from human or rodent islets, verifying their applicability for rapid assessment of islet function.

Conclusions: The homogeneous, rapid, and uncomplicated nature of insulin and C-peptide FRET sensors allows rapid assessment of β-cell function and could enable point-of-care determinations of insulin and C-peptide.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies
  • Base Sequence
  • Biosensing Techniques
  • C-Peptide / analysis
  • C-Peptide / genetics
  • C-Peptide / metabolism*
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Insulin / analysis
  • Insulin / genetics
  • Insulin / metabolism*
  • Insulin Secretion
  • Islets of Langerhans / metabolism*
  • Limit of Detection
  • Oligodeoxyribonucleotides / chemistry
  • Proinsulin / analysis
  • Proinsulin / metabolism
  • Radioimmunoassay


  • Antibodies
  • C-Peptide
  • Insulin
  • Oligodeoxyribonucleotides
  • Proinsulin