Premium
Ultra‐High to Ultra‐Low Drug‐Loaded Micelles: Probing Host–Guest Interactions by Fluorescence Spectroscopy
Author(s) -
Lübtow Michael M.,
Marciniak Henning,
Schmiedel Alexander,
Roos Markus,
Lambert Christoph,
Luxenhofer Robert
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201902619
Subject(s) - micelle , fluorescence , polymer , fluorescence spectroscopy , fluorescence correlation spectroscopy , chemistry , chemical engineering , drug , photon upconversion , curcumin , molecule , photochemistry , chemical physics , materials science , organic chemistry , aqueous solution , ion , physics , quantum mechanics , engineering , psychology , biochemistry , psychiatry
Polymer micelles are an attractive means to solubilize water insoluble compounds such as drugs. Drug loading, formulations stability and control over drug release are crucial factors for drug‐loaded polymer micelles. The interactions between the polymeric host and the guest molecules are considered critical to control these factors but typically barely understood. Here, we compare two isomeric polymer micelles, one of which enables ultra‐high curcumin loading exceeding 50 wt.%, while the other allows a drug loading of only 25 wt.%. In the low capacity micelles, steady‐state fluorescence revealed a very unusual feature of curcumin fluorescence, a high energy emission at 510 nm. Time‐resolved fluorescence upconversion showed that the fluorescence life time of the corresponding species is too short in the high‐capacity micelles, preventing an observable emission in steady‐state. Therefore, contrary to common perception, stronger interactions between host and guest can be detrimental to the drug loading in polymer micelles.