A Novel Fluorescent Probe for the Detection of Hydrogen Peroxide

Discovery of a highly selective fluorescent probe for hydrogen peroxide and its biocompatibility evaluation and bioimaging applications in cells and zebrafish

As one of the most widely distributed reactive oxygen species in vivo, hydrogen peroxide plays divergent and important roles in cell growth, differentiation and aging. When the level of hydrogen peroxide in the body is abnormal, it will lead to genome mutation and induce irreversible oxidative modification of proteins, lipids and polysaccharides, resulting in cell death or even disease. Therefore, it is significant to develop a sensitive and specific probe for real-time detection of hydrogen peroxide in vivo. In this study, the response mechanism between hydrogen peroxide and probe QH was investigated by means of HRMS and the probe showed good optical properties and high selectivity to hydrogen peroxide. Note that the evaluating of probe biocompatibility resulted from cytotoxicity test, behavioral test, hepatotoxicity test, cardiotoxicity test, blood vessel toxicity test, immunotoxicity test and neurotoxicity test using cell and transgenic zebrafish models with more than 20 toxic indices. Furthermore, the detection performance of the probe for hydrogen peroxide was evaluated by multiple biological models and the probe was proved to be much essential for the monitoring of hydrogen peroxide in vivo.

Ex Tenebris Lux: Illuminating Reactive Oxygen and Nitrogen Species with Small Molecule Probes

Reactive oxygen and nitrogen species are small reactive molecules derived from elements in the air─oxygen and nitrogen. They are produced in biological systems to mediate fundamental aspects of cellular signaling but must be very tightly balanced to prevent indiscriminate damage to biological molecules. Small molecule probes can transmute the specific nature of each reactive oxygen and nitrogen species into an observable luminescent signal (or even an acoustic wave) to offer sensitive and selective imaging in living cells and whole animals. This review focuses specifically on small molecule probes for superoxide, hydrogen peroxide, hypochlorite, nitric oxide, and peroxynitrite that provide a luminescent or photoacoustic signal. Important background information on general photophysical phenomena, common probe designs, mechanisms, and imaging modalities will be provided, and then, probes for each analyte will be thoroughly evaluated. A discussion of the successes of the field will be presented, followed by recommendations for improvement and a future outlook of emerging trends. Our objectives are to provide an informative, useful, and thorough field guide to small molecule probes for reactive oxygen and nitrogen species as well as important context to compare the ecosystem of chemistries and molecular scaffolds that has manifested within the field.

A highly selective coumarin-based chemosensor for dual sensing of Cu2+ and Zn2+ ions with logic gate integration and live cell imaging

In this paper, a coumarin-based Schiff base chemosensor has been synthesized and developed to detect Cu2+ and Zn2+ ions in nanomolar concentrations. The probe selectively distinguishes Cu2+ and Zn2+ from among several metal ions in DMF : H2O (7 : 3, v/v, pH 7.4) HEPES buffer. The structure of the probe and its sensing behavior were investigated by FT-IR, UV-vis, fluorescence, HRMS, and NMR analyses, along with X-ray crystallography and computational studies. CIH detects Zn2+ and Cu2+ using different strategies: CHEF-induced fluorescence enhancement and paramagnetic fluorescence quenching, respectively. Job's plots show a 1 : 1 binding interaction between CIH and Cu2+ or Zn2+ ions. The binding constant values for Cu2+ (1.237 × 105 M-1) and Zn2+ (1.24 × 104 M-1) suggest a better ability for Cu2+ to interact with CIH than Zn2+. An extremely high sensitivity of the probe was highlighted by its very low detection limits (LOD) of 5.36 nM for Cu2+ and 3.49 nM for Zn2+. The regeneration of the probe with the addition of EDTA in its complexes allows the formation of molecular logic gates. CIH has been successfully employed in mitotracking and intracellular detection of Zn2+ and Cu2+ in SiHa cells.

Design, Synthesis of Hydrogen Peroxide Response AIE Fluorescence Probes Based on Imidazo [1,2-a] Pyridine

Hydrogen peroxide (H2O2), a significant member of reactive oxygen species, plays a crucial role in oxidative stress and cell signaling. Abnormal levels of H2O2 in the body can induce damage or even impair body function, leading to the development of certain diseases. Therefore, real-time monitoring of H2O2 in living cells is very important. In this work, the aggregation-induced emission fluorescence probe 2-(2-((4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) benzyl) oxy) phenyl) imidazo [1,2-a] pyridine (B2) was designed and synthesized, which enables the long-term tracing of H2O2 in living cells. The addition of H2O2 to probe B2 results in a dramatic fluorescence enhancement around 500 nm. Notably, B2 can visualize both exogenous and endogenous H2O2 in living cells. The synthesis method for B2 is simple, has a high yield, and utilizes readily available materials. It exhibits advantages such as low toxicity, photostability, and good biocompatibility. Consequently, the developed fluorescent probe in this study has great potential as a reliable tool for determining H2O2 in living cells.

Umbelliferone and Its Synthetic Derivatives as Suitable Molecules for the Development of Agents with Biological Activities: A Review of Their Pharmacological and Therapeutic Potential

Umbelliferone (UMB), known as 7-hydroxycoumarin, hydrangine, or skimmetine, is a naturally occurring coumarin in the plant kingdom, mainly from the Umbelliferae family that possesses a wide variety of pharmacological properties. In addition, the use of nanoparticles containing umbelliferone may improve anti-inflammatory or anticancer therapy. Also, its derivatives are endowed with great potential for therapeutic applications due to their broad spectrum of biological activities such as anti-inflammatory, antioxidant, neuroprotective, antipsychotic, antiepileptic, antidiabetic, antimicrobial, antiviral, and antiproliferative effects. Moreover, 7-hydroxycoumarin ligands have been implemented to develop 7-hydroxycoumarin-based metal complexes with improved pharmacological activity. Besides therapeutic applications, umbelliferone analogues have been designed as fluorescent probes for the detection of biologically important species, such as enzymes, lysosomes, and endosomes, or for monitoring cell processes and protein functions as well various diseases caused by an excess of hydrogen peroxide. Furthermore, 7-hydroxy-based chemosensors may serve as a highly selective tool for Al3+ and Hg2+ detection in biological systems. This review is devoted to a summary of the research on umbelliferone and its synthetic derivatives in terms of biological and pharmaceutical properties, especially those reported in the literature during the period of 2017-2023. Future potential applications of umbelliferone and its synthetic derivatives are presented.

Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging

Fluorescent materials have great potential for use in biomedical applications due to their ease of functionalization and tunable fluorescence color [...].