A BODIPY-based fluorescent probe for simultaneous detection of H2O2 and viscosity during the pyroptosis process

Development of a dual-responsive ratiometric fluorescent probe for real-time sequential detection of H2O2 and Ag. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2025;333:125855. [PMID: 39946858 DOI: 10.1016/j.saa.2025.125855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Hydrogen peroxide (H2O2) and silver ions (Ag+) are of considerable interest due to their critical roles in chemical and biological processes and their potential environmental and health risks. In this study, a novel dual-response ratiometric fluorescent probe (FBHP), based on an internal charge transfer (ICT) mechanism, was designed and synthesized for the real-time dual detection of H2O2 and Ag+. The probe utilizes triphenylamine as a luminescent platform, while azacrown [N, S, O] groups and phenylboronic pinacol ester groups serve as recognition sites for Ag+ and H2O2, respectively. Experimental results demonstrate that FBHP exhibits high sensitivity and excellent selectivity for H2O2 and Ag+, achieving detection limits of 0.261 μM for H2O2 and 0.021 μM for Ag+. During sequential real-time detection of H2O2 and Ag+, the probe undergoes distinct three-channel fluorescence color changes, with fluorescence colors transitioning sequentially from red to blue and then to yellow. It also features a large Stokes shift of 194 nm and functions efficiently across a broad pH range (4 to 9). In conclusion, the real-time sequential dual-responsive ratiometric fluorescent probe FBHP offers significant advantages for the detection of H2O2 and Ag+, making it highly suitable for applications in environmental monitoring and biomedical research. This probe represents an efficient and reliable tool for analyzing and detecting H2O2 and Ag+ in various fields. Future work may focus on further structural modifications to enhance its detection performance and broaden its application scope.

A cascade strategy for vinyl chloride-substituted BODIPYs with tunable photophysical properties

An efficient and transition-metal-free method for the synthesis of unprecedented vinyl chloride-substituted BODIPYs has been developed through tandem Friedel-Crafts, enolization and chlorination reactions. This transformation offers high regioselectivity and stereoselectivity, enabling the synthesis of a variety of β-vinyl chloride-β'-acyl- and β,β'-divinyl chloride-substituted BODIPYs in a one-pot reaction at room temperature. Further functionalization gave a β,β'-divinyl chloride-substituted BODIPY with triphenyl phosphonium moieties, which showed favorable two-photon mitochondrion-targeting imaging capacity in living cells with intense deep-red fluorescence.

A Triple-Responsive and Dual-NIR Emissive Fluorescence Probe for Precise Cancer Imaging and Therapy by Activating Pyroptosis Pathway

Revealing changes in the tumor microenvironment is crucial for understanding cancer and developing sensitive methods for precise cancer imaging and diagnosis. Intracellular hydrogen peroxide (H2O2) and microenvironmental factors (e.g., viscosity and polarity) are closely linked to various physiological and pathological processes, making them potential biomarkers for cancer. However, a triple-response theranostic probe for precise tumor imaging and therapy has not yet been achieved due to the lack of effective tools. Herein, we present a mitochondria-targeting near-infrared (NIR) fluorescent probe, VPH-5DF, capable of simultaneously monitoring H2O2, viscosity, and polarity through dual NIR channels. The probe specifically detects H2O2 via NIR emission (λem = 650 nm) and shows high sensitivity to microenvironmental viscosity/polarity in the deep NIR channel (λem ≈ 750 nm). Furthermore, the probe not only monitors mitochondrial polarity, viscosity, and fluctuations in endogenous/exogenous H2O2 levels but also distinguishes cancer cells from normal cells through multiple parameters. Additionally, VPH-5DF can be employed to monitor alterations in H2O2 levels, as well as changes in viscosity and polarity, during drug-induced pyroptosis in living cells. After treatment with VPH-5DF, chemotherapy-induced oxidative damage to the mitochondria in tumor cells activated the pyroptosis pathway, leading to a robust antitumor response, as evidenced in xenograft tumor models. Thus, this triple-response theranostic prodrug offers a new platform for precise in vivo cancer diagnosis and anticancer chemotherapy.

Construction of cationic meso-thiazolium-BODIPY AIE fluorescent probes for viscosity imaging in dual organelles

Two new cationic meso-thiazolium-BODIPY-based water-soluble and red-shifted fluorescent probes were constructed for the first time. They can monitor cellular viscosity in dual organelles and show aggregation-induced emission (AIE), which is ascribed to the efficient restricted rotation of meso-thiazolium in viscous or hindered systems. Probe 3 with an N-benzyl group shows better AIE as compared to probe 2 with an N-methyl group.

Visualized Tracking and Multidimensional Assessing of Mitochondria-Associated Pyroptosis in Cancer Cells by a Small-Molecule Fluorescent Probe

Pyroptosis is closely related to the development and treatment of various cancers; thus, comprehensive studies of the correlations between pyroptosis and its inductive or inhibitive factors can provide new ideas for the intervention and diagnosis of tumors. The dysfunction of mitochondria may induce pyroptosis in cancer cells, which can be reflected by the fluctuations of the microenvironmental parameters in mitochondria as well as the changes of mitochondrial DNA level and morphology, etc. To precisely track and assess the mitochondria-associated pyroptosis process, simultaneous visualization of changes in multiphysiological parameters in mitochondria is highly desirable. In this work, we reported a nonreaction-based, multifunctional small-molecule fluorescent probe Mito-DK with the capability of crosstalk-free response to polarity and mtDNA as well as mitochondrial morphology. Accurate assessment of mitochondria-associated pyroptosis induced by palmitic acid/H2O2 was achieved through monitoring changes in mitochondrial multiple parameters with the help of Mito-DK. In particular, the pyroptosis-inducing ability of an antibiotic doxorubicin and the pyroptosis-inhibiting capacity of an anticancer agent puerarin were evaluated by Mito-DK. These results provide new perspectives for visualizing mitochondria-associated pyroptosis and offer new approaches for screening pyroptosis-related anticancer agents.

Mechanistic analysis of viscosity-sensitive fluorescent probes for applications in diabetes detection

Diabetes is one of the most detrimental diseases affecting the human life because it can initiate several other afflictions such as liver damage, kidney malfunctioning, and cardiac inflammation. The primary method for diabetes diagnosis involves the analysis of blood samples to quantify the level of glucose, while secondary diagnostic methods involve the qualitative analysis of obesity, fatigue, etc. However, all these symptoms start showing up only when the patient has been suffering from diabetes for a certain period of time. In order to avoid such delay in diagnosis, the development of specific fluorescent probes has attracted considerable attention. Prominent biomarkers for diabetes include abundance of certain analytes in blood serum, e.g., glucose, methylglyoxal, albumin, and reactive oxygen species; high intracellular viscosity; alteration of enzyme functionality, etc. Among these, high viscosity can greatly affect the fluorescence properties of various chromophores owing to the environment sensitivity of fluorescence spectra. In this review article, we have illustrated the application of some prominent fluorophores such as coumarin, BODIPY, xanthene, and rhodamine in the development of viscosity-dependent fluorescent probes. Detailed mechanistic aspects determining the influence of viscosity on the fluorescent properties of the probes have also been elaborated. Fluorescence mechanisms that are directly affected by the high-viscosity heterogeneous microenvironment are based on intramolecular rotations like twisted intramolecular charge transfer (TICT), aggregation-induced emission (AIE), and through-bond energy transfer (TBET). In this regard, this review article will be highly useful for researchers working in the field of diabetes treatment and fluorescent probes. It also provides a platform for the planning of futuristic clinical translation of fluorescent probes for the early-stage diagnosis and therapy of diabetes.