Photo-Responsive Self-Assembled Polymeric Nanoparticle Probes for 19F MRI Theranostics

F-19 magnetic resonance imaging (MRI)-assisted drug deliveryprovides the possibility to monitor and track drug transportationdetails in situ. A series of photo-responsive amphiphilic block copolymersconsisting of hydrophilic poly-(ethylene glycol) and F-19-containinghydrophobic segments, poly-(2,2,2-trifluoroethyl acrylate) (PTFEA),with different chain lengths were synthesized by reversible addition-fragmentationchain-transfer polymerization. In particular, the photo-sensitivefunctional group of o-nitrobenzyl oxygen was introducedto control the photolysis behavior of the copolymers under ultravioletirradiation. With the extension of the hydrophobic chain length, thedrug loading capacity and photoresponsivity were both enhanced, whilethe chain mobility of PTFEA was suppressed, and the (FMRI)-F-19 signal was attenuated. When the polymerization degree of PTFEAwas about 10, the nanoparticles exhibit detectable (FMRI)-F-19 signals and sufficient drug loading capacity (loading efficiency= 10%, cumulative release = 49%). These results offer a promisingsmart theranostic platform for F-19 MRI.

Automated summary

F-19 MRI-assisted drug delivery allows for real-time monitoring and tracking of drug transportation. Amphiphilic block copolymers containing hydrophilic polyethylene glycol and F-19-containing hydrophobic segments were synthesized, with the photolysis behavior of the copolymers controlled using o-nitrobenzyl oxygen. Increasing the hydrophobic chain length enhanced drug loading capacity and photoresponsivity, while reducing chain mobility and FMRI-F-19 signal. Nanoparticles with a PTFEA polymerization degree of 10 exhibited detectable FMRI-F-19 signals and sufficient drug loading capacity (loading efficiency = 10%, cumulative release = 49%), providing a promising smart theranostic platform for F-19 MRI.