BINOL-Based Fluorescent Sensor for Recognition of Cu(II) and Sulfide Anion in Water

A multifunctional fluorescent sensor based on a cyclen-appended BINOL derivative (<b>R-1</b>) was synthesized and characterized. It can display on–off-type fluorescence change with high selectivity toward Cu­(II) among 19 metal ions in 100% aqueous solution. Furthermore, the in situ generated <b>R-1–Cu­(II)</b> ensemble could recover the quenched fluorescence upon the addition of sulfide anion resulting in a off–on-type sensing with a detection limit of micromolar range in the same medium. No interference was observed from other biothiols and anions, including GSH, l-Cys, DTT, and sulfates, making it a highly sensitive and selective sulfide probe

Fluorescence Imaging of Diabetic Cataract-Associated Lipid Droplets in Living Cells and Patient-Derived Tissues

Diabetic cataract (DC) surgery carries risks such as slow wound healing, macular edema, and progression of retinopathy and is faced with a deficiency of effective drugs. In this context, we proposed a protocol to evaluate the drug’s efficacy using lipid droplets (LDs) as the marker. For this purpose, a fluorescent probe PTZ-LD for LDs detection is developed based on the phenothiazine unit. The probe displays polarity-dependent emission variations, i.e., lower polarity leading to stronger intensity. Especially, the probe exhibits photostability superior to that of Nile Red, a commercial LDs staining dye. Using the probe, the formation of LDs in DC-modeled human lens epithelial (HLE) cells is validated, and the interplay of LDs–LDs and LDs-others are investigated. Unexpectedly, lipid transfer between LDs is visualized. Moreover, the therapeutic efficacy of various drugs in DC-modeled HLE cells is assessed. Ultimately, more LDs were found in lens epithelial tissues from DC patients than in cataract tissues for the first time. We anticipate that this work can attract more attention to the important roles of LDs during DC progression

Novel Tumor-Specific and Mitochondria-Targeted near-Infrared-Emission Fluorescent Probe for SO₂ Derivatives in Living Cells

Endogenous sulfur dioxide (SO₂) is an important gaseous signal molecule, which was also regarded as one of the reactive sulfur spaces (RSS) and closely related to cardiovascular diseases and many neurological disorders. However, the design and synthesis of fluorescent probes with near-infrared-emission which can detect mitochondrial SO₂ and its derivatives in living cells still remain unresolved. Herein, a biotin and coumarin-benzoindole conjugate <b>BCS-1</b> was presented as a ratiometric and colorimetric fluorescent probe for tracing SO₂ derivatives with excellent selectivity and rapid responsibility. Notably, it is the first mitochondria-targeted near-infrared-emission probe that could selectively detect SO₂ in tumor cells. <b>BCS-1</b> could selectively enter into mitochondria of tumor cells, and the detection limit for SO₂ derivatives was determined as 72 nM

PLK1-Targeted Fluorescent Tumor Imaging with High Signal-to-Background Ratio

As significantly expressed during cell division, polo-like kinase 1 (PLK1) plays crucial roles in numerous mitotic events and has attracted interest as a potential therapeutic marker in oncological drug discovery. We prepared two small molecular fluorescent probes, <b>1</b> and <b>2</b>, conjugated to <b>SBE13</b> (a type II PLK1 inhibitor) to investigate the PLK1-targeted imaging of cancer cells and tumors. Enzymatic docking studies, molecular dynamics simulations, and <i>in vitro</i> and <i>in vivo</i> imaging experiments all supported the selective targeting and visualization of PLK1 expressing cells by probes <b>1</b> and <b>2</b>, and probe <b>2</b> was successfully demonstrated to image PLK1-upregulated tumors with remarkable signal-to-background ratios. These findings represent the first example of small-molecule based fluorescent imaging of tumors using PLK1 as a target, which could provide new avenues for tumor diagnosis and precision therapeutics