Fluorescent
thermometers with near-infrared (NIR) emission play
an important role in visualizing the intracellular temperature with
high resolution and investigating the cellular functions and biochemical
activities. Herein, we designed and synthesized a donor−Π–acceptor
luminogen, 2-([1,1′-biphenyl]-4-yl)-3-(4-((E)-4-(diphenylamino)styryl) phenyl) fumaronitrile (TBB) by Suzuki
coupling reaction. TBB exhibited twisted intramolecular charge transfer-based
NIR emission, aggregation-induced emission, and temperature-sensitive
emission features. A ratiometric fluorescent thermometer was constructed
by encapsulating thermosensitive NIR fluorophore TBB and Rhodamine
110 dye into an amphiphilic polymer matrix F127 to form TBB&R110@F127
nanoparticles (TRF NPs). TRF NPs showed a good temperature sensitivity
of 2.37%·°C–1, wide temperature response
ranges from 25 to 65 °C, and excellent temperature-sensitive
emission reversibility. Intracellular thermometry experiments indicated
that TRF NPs could monitor the cellular temperature change from 25
to 53 °C for Hep-G2 cells under the photothermal therapy agent
heating process, indicating the considerable potential applications
of TRF NPs in the biological thermometry field.
We demonstrate, for the first time, an electrochemical sensor that provides antipodal signals upon application of square wave voltammetry (SWV), for enantioselective recognition of 3,4-dihydroxyphenylalanine based on chiral single-walled carbon nanotubes (SWCNTs) in the presence of sulphuric acid. Interestingly, the enantioselectivity was not observed using the common method of cyclic voltammetry (CV) but the SWV peak currents of enantiomers were found to be quite different and hence the enantiomers could be successfully recognized. Moreover, the antipodal signals provided by two SWV scan modes offer the possibility for results to be confirmed mutually, showing a great practical value and analytical application prospects.
High-quality multimodal imaging requires exogenous contrast agents with high sensitivity, spatial–temporal resolution, and high penetration depth for the accurate diagnosis and surveillance of cancer.
Two-dimensional covalent organic frameworks (2D COFs) with both water detection and adsorption properties are highly attractive for both basic research and applied research. Herein, we constructed hydrazone-linked Pythz-COF and urea-linked...
Fluorescence probes with strong near-infrared (NIR) emission and water solubility are considered useful visualization tools for localization marking as well as investigating cell migration and transplantation. Here, we designed and synthesized a new donor-πacceptor (D-π-A) fluorogen, 2-(4-[(E)-4-(diphenylamino)styryl]phenyl)-3-(4′-[1,2,2-triphenylvinyl]-[1,1′biphenyl]-4-yl) fumaronitrile (TB-TPE). TB-TPE exhibits twisted intramolecular charge transfer (TICT) and aggregation-induced emission (AIE) in the NIR region, with an emission peak at 714 nm and a fluorescence quantum yield (Qy) of 6.6% in the solid state. By encapsulating TB-TPE with polystyrene-polyethylene glycol (PS-PEG), watersoluble TB-TPE-PS-PEG nanoparticles (TP NPs) are fabricated, which display polymer encapsulationenhanced emission with a Qy of 46.5% due to the strong restriction effect on the TICT process and the destruction of H aggregation for TB-TPE by the polymer matrix. Au-coated Fe 3 O 4 (Fe 3 O 4 @Au) nanocrystals were then embedded in the TP NPs to form highly fluorescent TB-TPE-Fe 3 O 4 -Au-PS-PEG nanoparticles (TFAP NPs) with a Qy of 39.7%. Our demonstration of successful cellular imaging of TP NPs for Hep-G2 cells and multimodality imaging of TFAP NPs in mouse liver tumors indicates that polymer-encapsulated TB-TPE offers great prospects as a multifunctional fluorescence probe for bioimaging.
Two kinds of online preconcentration techniques including large-volume sample stacking-sweeping and selective-exhaustive injection-sweeping (SEI-S) were employed in CE to develop a rapid, simple and sensitive method for determination of melamine (MM) and its derivatives such as ammeline (AMN), ammelide (AMD) and cyanuric acid (CA) in liquid milk products. Though the sensitivity of large-volume sample stacking-sweeping is not particularly high, it can be used to detect all the four compounds simultaneously. However, it is very difficult to improve the sensitivity of these four compounds by using single SEI-S method directly, owing to their completely different extents of protonation or deprotonation. Grouping can solve this problem perfectly. After the four compounds are divided into two groups (MM/AMN and AMD/CA), cation-SEI-S or anion-SEI-S can be applied for their online stacking. In cation-SEI-S, the detection limits for MM and AMN were both 0.01 ng/mL based on the signal-to-noise ratio of 3. In anion-SEI-S, the detection limits were 0.05 and 0.02 ng/mL for CA and AMD, respectively. Results of this study show a great potential for the SEI-S method to be a useful tool for the rapid and sensitive determination of MM and its derivatives in liquid milk products.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.