Synthesis of non-modified near-infrared carbon dots for hypochlorite detection and cell membrane imaging.

Devising carbon dots with long wavelength emission (red light or near infrared), high selectivity and good bio-compatibility is critical in fluorescence detection and imaging, but achieving this goal remains a great challenge. Herein, near-infrared emissive carbon dots (NIR-CDs) with obvious emission characteristic of 653 nm were synthesized through hydrothermally treatment of toluidine bule and gallic acid. Noticeably, the NIR-CDs exhibited excellent selectivity and sensitivity to hypochlorite (ClO), and the limit of detection is as low as 42.

A D-π-A-based near-infrared fluorescent probe with large Stokes shift for the detection of cysteine in vivo.

D-π-A dyes are an ideal strategy for building near-infrared fluorescent probes that have a large Stokes shift due to their excellent properties of adjustable emission wavelength and Stokes shift. Developing a near-infrared (NIR) fluorescent probe (JTPQ-Cys) capable of detecting cysteine (Cys) was the aim of this study. In JTPQ-Cys, julolidine served as the electron donor (D) and quinoline as the electron acceptor (A), with 3,4-ethylenedioxythiophene as the π-bridge.

Facile synthesis of non-modified yellow emission silicon quantum dots and their visualization of hydrogen sulfide in living cells and onion tissues.

Yellow fluorescent silicon quantum dots (y-SiQDs) with 22.2% fluorescence quantum yield were synthesized by a simple hydrothermal method using 3-glycidoxypropyl triethoxysilane (GOTS) and m-aminophenol. The excitation wavelength is 550 nm with an emission wavelength of 574 nm, which effectively avoids the interference of biological autofluorescence.

A turn-on homodimer fluorescent probe based on homo-FRET for the sensing of biothiols in lysosome: a trial of a new turn-on strategy.

Fluorescence resonance energy transfer (FRET) is often applied to construct fluorescent probes for acquiring high selectivity and sensitivity. According to the FRET theory, a homodimer composed of two identical fluorophores with a small Stokes shift has only weak fluorescence due to homo-FRET between fluorophores, and the fluorescence could be recovered after the destruction of the homodimer. In this study, we designed and synthesized a homodimer fluorescent probe, namely 1,3,5,7-tetramethyl-8-(4'-phenylthiophenol)-boron difluoride-dipyrrole methane dimer (D-TMSPB), based on this turn-on strategy.

A fluorescent probe for carbon monoxide based on allyl ether rather than allyl ester: A practical strategy to avoid the interference of esterase in cell imaging.

Pd-mediated Tsuji-Trost reaction is a practical strategy to design fluorescent probes for carbon monoxide (CO) sensing, and in such reaction CO can reduce Pd to Pd in-situ and remove allyl groups on fluorophores. In most of these probes, esters are commonly used to link allyl on fluorophores. We found that the ester groups could be hydrolyzed by esterase activity of fetal bovine serum (FBS), while FBS is a requisite in cell culture, and the hydrolysis could interfere the Pd-mediated Tsuji-Trost reaction.

Screening of a highly effective fluorescent derivatization reagent for carbonyl compounds and its application in HPLC with fluorescence detection.

Carbonyl compounds are widely distributed in organisms, and the commonly used methods for determination of them like UV/fluorescence/mass spectrometry always require derivatization reagents. However, the reported derivatization reagents have significant difference in reactivity, which is very unfavorable for developing highly reactive reagent. In this study, we theoretically investigated the factors affecting the reactivity of hydrazine-based derivatization reagents, and proposed a strategy for filtering highly reactive reagents by quantum chemical calculation.