Near-Infrared Luminescent Materials:Synthesis And Application In Bioimaging In Vivo

Luminescent bioimaging offers a unique approach for visualizing multi-scale morphological details from living cells to small-animals. Near-infrared (NIR) and upconversion luminescence (UCL) materials could be used as probes to effectively reduce the autofluorescence from the biosamples, and have been applied in bioimaging in vivo. However, few luminescent materials in monitoring special functional analytes within small-animal have been developed to date. In this thesis, a series of NIR probes have been designed and synthesized to monitor the special ions and molecules by luminescence in vivo bioimaging techniques, including1. A Highly Sensitive NIR Fluorescent Dye for in vivo Bioimaging of Copper IonsA NIR rhodamine derivative (Rh-730-NNH2) has been designed and synthesized as a fluorescet chemodosimeter for visualizing copper pools in living animals. By cyclizing hydrazine reaction, Rh-730-NNH2 provided a selective and sensitive turn-on response to Cu2+ ion. Using the NIR luminescence as a detection signal, the detection limit of Cu2+ for Rh-730-NNH2 was as low as 0.05μM, lower than the maximal level (1.30 ppm) of drinking water set by U. S. EPA. Importantly, the Rh-730-NNH2 was shown to be capable of monitoring Cu2+ by NIR luminescence bioimaging in vivo.2. A Highly Selective NIR Dye for in vivo Bioimaging of HypochlorousWe demonstrated a NIR rhodamine derivative (Rh-815) as a fluorescet chemodosimeter for visualizing labile HOC1 in living animals. Using the NIR luminescence at 815±2 nm as a detection signal, Rh-815 could detect the HClO with high sensitivity and selectivity. Importantly, the Rh-815 as luminescent probe was shown to be capable of monitoring HOC1 by NIR luminescence bioimaging in vivo.3. A Cyanine-modified Nanosystem for in vivo Upconversion Luminescence Bioimaging of MethylmercuryA hydrophobic heptamethine cyanine dye (hCy7) modified by two long alkyl moieties and amphiphilic polymer (P-PEG)-modified nanophosphors (hCy7-UCNPs) was fabricated as a highly sensitive probe for UCL bioimaging of MeHg+. Further application of hCy7-UCNPs for sensing MeHg+ was confirmed by an optical titration experiment and upconversion luminescence live cell imaging. Using the ratiometric upconversion luminescence as a detection signal, the detection limit of MeHg+ for this nanosystem in water was as low as 0.18 ppb. Importantly, the hCy7-UCNPs nanosystem was shown to be capable of monitoring MeHg+ ex vivo and in vivo by upconversion luminescence bioimaging.4. A Dual-NIR Emissive nanoparticles for in vivo BiomagingA new rhodamine derivative Rh-730 has been synthesized and shows a NIR luminescence emission centered at 730 nm. The Rh-730 was further modified on the surface of Yb3+,Er3+,Nd3+-codoped nanocrystal (OA-cs UCNPs:Nd) and a nanocomposite (Rh-730-UCNP:Nd) was fabricated. Interestingly, the Rh-730-UCNP:Nd displayed dual NIR-to-NIR emissions under 670 nm and 808 nm excitation, and were successfully used for multi-channel bioimaging in vivo of lymph node in living mice.