Contrast agents based on switchable near-infrared fluorescent nanoprobes for highly sensitive optical imaging. (January 2017)

• Record Type: Journal Article
• Authors: Park, Hye Sun; Cho, Mi Young; Noh, Young-Woock; Hong, Kwan Soo; Lim, Yong Taik
• Is Part Of: Dyes and pigments. Volume 136(2017)
• Page Start: 583
• Page End: 589
• Publication Date: 2017-01
• Subjects: pH-responsive -- Activatable fluorophore -- Nanoparticles -- Indocyanine green -- Molecular imaging; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2016.09.017
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: We have synthesized and characterized photophysical properties of a novel contrast agent based on switchable near-infrared (NIR) fluorescent nanoprobes that enables optical imaging with a higher sensitivity than conventional contrast agents allow. The high sensitivity was a result not only of the intrinsically high signal-to-background ratio that could be obtained in the NIR spectral region, but also from the increased signal intensity that was provided by using activatable nanoprobes. The NIR fluorescent nanoprobes were synthesized by encapsulating indocyanine green (ICG) into pH-responsive polymer nanoparticles. The intensity of the NIR fluorescence signal from the nanoparticles increased about 11-fold in acidic solution, due to the release of ICG molecules from the nanoparticles. The efficacy of fluorescence recovery from the quenched state to the de-quenched state could be modulated by controlling the relative concentrations between pH-responsive polymer and ICG. The fluorescence recovery properties of switchable NIR nanoprobes were also evaluated by cellular uptake experiments. Our experimental results support the use of pH-responsive nanoparticles with incorporated contrast agents as activatable molecular imaging nanoprobes. Graphical abstract: Highlights: Switchable near-infrared fluorophores showing higher sensitivity were synthesized. The signal intensity of pH-responsive fluorophores increased about 11-fold in acidic solution. Transition from quenched to de-quenched state recovered fluorescence signal. The activatable molecular imaging probes can be used for the labeling of target cells.