Quantum dots as templates for self-assembly of photoswitchable polymers: small, dual-color nanoparticles capable of facile photomodulation.
A photomodulatable amphiphilic polymer has been synthesized with a backbone of poly[isobutylene-alt-maleic anhydride] and pendant dodecyl alkyl chains, Lucifer Yellow (LY) fluorescent probes, and diheteroarylethenes photochromic (PC) groups. The latter serve as reversible UV-activated FRET acceptors for the LY donors. We characterized the spectral and switching properties of the polymer in an organic solvent (CHCl(3)). In an aqueous medium the polymer forms polymersomes, constituting fluorescence probes ~75 nm in diameter. Self-assembly of the polymer on the surface of a quantum dot (QD) serving as a template creates a dual-color photoswitchable nanoparticle (psNP) with improved properties due to the increase in polymer density and efficiency of PC photoconversion. The psNP exhibits a second QD red emission band that functions as an internal standard requiring only a single excitation wavelength, and is much reduced in size (<20 nm diameter) compared to the polymersomes. The QD template also greatly increases the depth of modulation by photochromic FRET of the LY emission monitored by both steady-state and time-resolved (lifetime) fluorescence (from 20%→70%, and from 12%→55%, respectively).
Laboratory of Cellular Dynamics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
Sebastián A
SA
Díaz
Luciana
L
Giordano
Julio C
JC
Azcárate
Thomas M
TM
Jovin
Elizabeth A
EA
Jares-Erijman
D003116:Color; D031541:Fluorescence Resonance Energy Transfer; D007700:Kinetics; D053758:Nanoparticles; D011108:Polymers / Q000737:chemistry*; D045663:Quantum Dots; D012997:Solvents / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
D011108:Polymers; D012997:Solvents