Spiropyran-Based Photochromic Polymer Nanoparticles with Optically Switchable Luminescence

• Published in: Journal of the American Chemical Society Vol. 128; no. 13; pp. 4303 - 4309
• Main Authors: Zhu, Ming-Qiang, Zhu, Linyong, Han, Jason J, Wu, Wuwei, Hurst, James K, Li, Alexander D. Q
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 05.04.2006; Amer Chemical Soc
• Subjects: Acrylamides - chemistry; Applied sciences; Benzopyrans - chemistry; Chemistry; Chemistry, Multidisciplinary; Electrical, magnetic and optical properties; Exact sciences and technology; Fluorescence; Humans; Hydrophobic and Hydrophilic Interactions; Indoles - chemistry; Luminescence; Microscopy, Electron, Transmission; Models, Molecular; Nanostructures - chemistry; Nitro Compounds - chemistry; Organic polymers; Photochemistry; Physical Sciences; Physicochemistry of polymers; Polystyrenes - chemistry; Properties and characterization; Pyrimidinones - chemistry; Science & Technology; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; MEMORIES; ENERGY-TRANSFER; PROTEIN; ACID; DERIVATIVES; GREEN; Nitrogen heterocycle polymer; Photochromism; Optical properties; Photoluminescence; Polydispersed particle; Particle suspension; Radiative lifetimes; Quantum yield; Spiropyran dye; Fluorescence microscopy; Fluorescence spectrometry; Submicron particle
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja0567642

Polymer nanoparticles of 40−400 nm diameter with spiropyran−merocyanine dyes incorporated into their hydrophobic cavities have been prepared; in contrast to their virtually nonfluorescent character in most environments, the merocyanine forms of the encapsulated dyes are highly fluorescent. Spiro−mero photoisomerization is reversible, allowing the fluorescence to be switched “on” and “off” by alternating UV and visible light. Immobilizing the dye inside hydrophobic pockets of nanoparticles also improves its photostability, rendering it more resistant than the same dyes in solution to fatigue effects arising from photochemical switching. The photophysical characteristics of the encapsulated fluorophores differ dramatically from those of the same species in solution, making nanoparticle-protected hydrophobic fluorophores attractive materials for potential applications such as optical data storage and switching and biological fluorescent labeling. To evaluate the potential for biological tagging, these optically addressable nanoparticles have been delivered into living cells and imaged with a liquid nitrogen-cooled CCD.