Micelle

Aqueous solution

Chemistry

Materials science

Physics

Drug carrier

Kinetics

Biophysics

Quantum mechanics

Nanotechnology

Organic chemistry

Biology

Pharmacology

Drug delivery

Medicine

Drug

ACS Nano

Polymer micelles are one of the most investigated nanocarriers for drug delivery; many have entered clinical trials and some are in clinic use, but their delivery systems have not yet shown the expected high therapeutic efficacy in clinics. Further understanding their in vivo behaviors, particularly how quickly and by what mechanism polymer micelles are cleared (i.e., via micelles or unimers) once injected, is key to solving this dilemma. Herein, we hope to answer these questions for the clinically relevant polyethylene glycol-block-poly(ε-caprolactone) (PEG-PCL) and PEG-block-poly(d,l-lactide) (PEG-PDLLA) micelles. A small fraction of the hydrophobic chain ends was conjugated with a pair of fluorescence resonance energy transfer (FRET) dyes, Cy5 and Cy5.5, and used to fabricate FRET micelles whose FRET efficiency was correlated to the percentage of polymer chains in the micelles, the micelle degree. In vitro, serum proteins induced PEG-PCL micelle dissociation to some extent; mouse serum or blood surprisingl...

The Blood Clearance Kinetics and Pathway of Polymeric Micelles in Cancer Drug Delivery