Self-Reporting Degradable Fluorescent Grafted Copolymer Micelles Derived from Biorenewable Resources

A series of hydrolytically degradable fluorescent poly(ferulic acid-co-tyrosine)-g-mPEG graft copolymers were synthesized and shown to undergo self-assembly in aqueous media to yield fluorescent micelles. The polymers and their micellar assemblies exhibited greater fluorescence emission intensity than did their small molecular building blocks, which provides a self-reporting character that has potential for monitoring the polymer integrity and also for performing in theranostics applications. The amphiphilic graft-copolymers were synthesized by Cu-assisted azide-alkyne "click" addition of azido-functionalized mPEG polymers onto fluorescent degradable hydrophobic copolymers displaying randomly distributed alkyne side-chain groups along their biorenewably derived poly(ferulic acid-co-tyrosine) backbones. The morphologies and photophysical properties of the supramolecular assemblies generated in aqueous solutions were evaluated by DLS, TEM, AFM, and steady-state optical spectroscopies. The 15-30 nm sized micelles behaved as broad-band emitters in the 350-600 nm range, which highlights their potential as self-reporting nanomaterials for in vitro studies.