Study of the intrinsic fluorescence of a highly branched cationic dendrimer, poly (Ethyleneimine) (PEI)

Viktória Tóth, Péter Hermann, Dániel Végh, Tivadar Zelles, Zoltán Géczi

Research output: Contribution to journalArticle


Poly(ethyleneimine) (PEI) is a weakly basic, synthetic, polycationic polymer, due to the presence of primary, secondary, and tertiary amino groups. The amino groups are responsible for the variety of applications of PEI (e.g., transfection, bioimaging, solar cell, etc.). Our study presents some new and reproducible methods for the quantification of molecular or mass concentration of highly branched PEI of different molecular weights (800-2000-25,000-750,000 MW PEI). In the course of the direct method, spectrophotometry and fluorometry were applied to determine the absorption and fluorescence of PEI dilution series. An increase in the MW at the same concentration produces a higher count number because of the higher number of amino groups in PEI molecules. The character of increment in fluorescence intensity is essentially different in the case of mass concentrations and molar concentrations. The increment of the fluorescence intensity related to the molar concentration is non-linear. In the case of mass concentration, the slope is linear. Moreover, their fluorescence is enhanced with the decrease in pH values. The spectrophotometry is a reliable method for measuring the quantity of PEI molecules in solution. Our data help in recognizing the detailed properties of PEI in dendrimer research.

Original languageEnglish
Article numbermolecules24203690
Issue number20
Publication statusPublished - Oct 14 2019



  • Biodegradability
  • Biopolymers
  • Dendrimer
  • Intrinsic fluorescence
  • Molecular weight
  • Polyethyleneimine

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemistry (miscellaneous)
  • Molecular Medicine
  • Pharmaceutical Science
  • Drug Discovery
  • Physical and Theoretical Chemistry
  • Organic Chemistry

Cite this