BODIPY-conjugated thermoresponsive copolymer as a fluorescent thermometer based on polymer microviscosity.
ABSTRACT A simple copolymer, poly(NIPAM-co-BODIPY), consisting of N-isopropylacrylamide (NIPAM) and boradiazaindacene (BODIPY) units, behaves as a fluorescent thermometer in water. The copolymer exhibits weak fluorescence at <23 degrees C, but the intensity increases with a rise in temperature up to 35 degrees C, enabling an accurate indication of the solution temperature at 23-35 degrees C. The heat-induced fluorescence enhancement is driven by an increase in the polymer microviscosity, associated with a phase transition of the polymer from the coil to globule state. The viscous domain formed inside the globule-state polymer suppresses the rotation of the meso-pyridinium group of the excited-state BODIPY units, resulting in heat-induced fluorescence enhancement. The polymer shows reversible fluorescence enhancement/quenching regardless of the heating/cooling process and displays high reusability with a simple recovery process.
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ABSTRACT: Fluorescence imaging in deep tissue with high spatial resolution is highly desirable because it can provide details about tissue's structural, functional, and molecular information. Unfortunately, current fluorescence imaging techniques are limited either in penetration depth (microscopy) or spatial resolution (diffuse light based imaging) as a result of strong light scattering in deep tissue. To overcome this limitation, we developed an ultrasound-switchable fluorescence (USF) imaging technique whereby ultrasound was used to switch on/off the emission of near infrared (NIR) fluorophores. We synthesized and characterized unique NIR USF contrast agents. The excellent switching properties of these agents, combined with the sensitive USF imaging system developed in this study, enabled us to image fluorescent targets in deep tissue with spatial resolution beyond the acoustic diffraction limit.Scientific Reports 01/2014; 4:4690. · 5.08 Impact Factor
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ABSTRACT: A type of BODIPY derivatives was designed and synthesized by the N-alkylation reaction of meso-(4-pyridinyl)-substituted BODIPY. The water-solubility of entire molecule was improved to a large extent as a result of the formation of cationic quaternary ammonium salt, while the strong fluorescence inherent to the BODIPY dye fragment is extinguished on alkylation of the pyridine N atom due to the photo-induced electron transfer (PET) process. The N-alkylated BODIPY derivative 4, as a novel water-soluble "Turn-On" fluorescent probe for the discrimination of H2O2, was constructed by incorporating 4-(Bromomethyl)benzeneboronic acid pinacol ester moiety, which showed highly selective fluorescent response to H2O2 against other interferences of ROS and RNS species under physiological conditions, and the reaction mechanism of boronate oxidation was conﬁrmed by (1)H NMR, mass spectrum and optical spectroscopy analysis. As a biocompatible probe in biological systems, probe 4 was successfully applied for monitoring and imaging of H2O2 both in vitro and in vivo using HepG2/LO2 cells and angelfish.Biosensors & bioelectronics 01/2014; 56C:58-63. · 5.43 Impact Factor
- Dyes and Pigments 01/2014; 111:81–90. · 3.53 Impact Factor