Amphiphilic Fluorinated Unimer Micelles as Nanocarriers of Fluorescent Probes for Bioimaging

Abstract

The unique self-assembly properties of unimer micelles are exploited for the preparation of fluorescent nanocarriers embedding hydrophobic fluorophores. Unimer micelles are constituted by a (meth)­acrylate copolymer with oligoethyleneglycol and perflurohexylethyl side chains (PEGMA90-co-FA10) in which the hydrophilic and hydrophobic comonomers are statistically distributed along the polymeric backbone. Thanks to hydrophobic interactions in water, the amphiphilic copolymer forms small nanoparticles (<10 nm), with tunable properties and functionality. An easy procedure for the encapsulation of a small hydrophobic molecule (C153 fluorophore) within unimer micelles is presented. UV–vis, fluorescence, and fluorescence anisotropy spectroscopic experimental data demonstrate that the fluorophore is effectively embedded in the nanocarriers. Moreover, the nanocarrier positively contributes to preserve the good emissive properties of the fluorophore in water. The efficacy of the dye-loaded nanocarrier as a fluorescent probe is tested in two-photon imaging of thick ex vivo porcine scleral tissue.

Tuning nanoparticles’ internal structure: fluorinated single-chain nanoparticles (SCNPs) generated by chain collapse of random copolymers

“…When collapsed in water as a selective solvent, those labels experience a well-defined, hydrophobic, and dense surrounding inside the core of the SCNPs, whereas THF as a nonselective solvent produces more sparse, less defined structures in which the hydrophobic compartments are positioned in multiple regions distributed across the particle in a sparse structure. 27 A similar pathway, dependent on the assembly/collapse process leading to compartmentation was observed by Delledonne et al 28 reporting the formation of unimer micelles serving as carriers for a fluorescent dye for biological applications. A random copolymer, composed of hydrophilic/hydrophobic segments, then generated small unimolecular micelles (<10 nm), featuring a hydrophobic fluorinated core formed through hydrophobic/hydrophilic interactions in water.…”

“…Overall by this modification the dye molecule will preferentially diffuse into the aliphatic compartment, the same principle applies to the dye with the fluorinated side chain. The technique has been previously employed by Delledonne et al 28 and was now adapted for our system (see the ESI†) to check for the formation of internal compartments inside the SCNPs.…”

3-Perfluoroalkylated fluorescent coumarin dyes: rational molecular design and photophysical properties

“…Eng., 2024, 9, 332-344 (F max ), brighter fluorescence, greater photostability in solutions, and applications for stable signal generation in imaging, have been reported. 6 However, there have been only a few reports on the fluorescent properties of 4-trifluoromethylated coumarins in the solid state 7,8 thus far (Fig. 2(a)).…”