A Highly Sensitive Fluorescent Probe for HClO and Its Application in Live Cell Imaging

A Chitosan-Based Fluorescent Probe Combined with Smartphone Technology for the Detection of Hypochlorite in Pure Water

Using chitosan as a raw material, 1,8-naphthimide as the fluorescent chromophore, and sulfur-containing compounds as the recognition groups, a novel naphthimide-functionalized chitosan probe, CS-BNS, for the detection of ClO- was successfully synthesized. The modification of chitosan was verified by SEM, XRD, FTIR, mapping, 13C-NMR, TG and the structure of the probe molecule was characterized. The identification performance of the probes was studied using UV and fluorescence spectrophotometers. The results show that CS-BNS exhibits a specific response to ClO- based on the oxidative reaction of ClO- to the recognition motifs, as well as a good resistance to interference. And the probe has high sensitivity and fast response time, and can complete the detection of ClO- in a pure water system within 60 s. The probe can also quantify ClO- (y = 30.698x + 532.37, R2 = 0.9833) with a detection limit as low as 0.27 μM. In addition, the combination of the probe with smartphone technology enables the visualization and real-time monitoring of ClO-. Moreover, an identification system for ClO- was established by combining the probe with smartphone technology, which realized the visualization and real-time monitoring of ClO-.

A dual-mode probe based on AIE and TICT effects for the detection of the hypochlorite anion and its bioimaging in living cells

Based on aggregation-induced emission (AIE) and twisted intramolecular charge transfer (TICT) mechanisms, a fluorescent probe SWJT-12 for the detection of ClO^- was designed by using the CN bond as a reactive group. This synthesized probe can react with ClO^- in a high aqueous phase, and it shows a large Stokes shift (144 nm) and low biological toxicity. Its limit of detection was calculated to be 0.28 μM. Furthermore, SWJT-12 was successfully used for ratiometric imaging of the exogenous hypochlorite anion in living cells.

Execution of aggregation-induced emission as nano-sensors for hypochlorite detection and application for bioimaging in living cells and zebrafish

Hypochlorite (ClO^-) could be used as a diagnostic marker for inflammation and related diseases. Although there have been many reports on probes for ClO^- imaging, there was still a lack of specificity and anti-interference ability. Herein, carbazole (NEC) and tetraphenylethylene (TPE) equipped with thiobarbituric acid (TBA), NEC-TBA and TPE-TBA, were synthesized and used as a fluorescence biosensor for monitoring ClO^- with aggregation-induced emission (AIE) effect. we identified that TPE-TBA, with formed nanoparticles in the mean grain size at 76 nm (5 μM), was a superior probe to target ClO^- over other analytes with fluorescence "turn off" strategy. Subsequently, to explore the bioimaging application, TPE-TBA was able to sense exogenous ClO^- in living HeLa cells through fluorescence imaging. In zebrafish model, TPE-TBA effectively captured exogenous ClO^- in the entire organization of zebrafish. Overall, these AIE-based probes merit further development as organism targeting ClO^- sensors.

Cancer immunotherapy with immunoadjuvants, nanoparticles, and checkpoint inhibitors: Recent progress and challenges in treatment and tracking response to immunotherapy

Chemotherapy, surgery, and radiation are accepted as the preferred treatment modalities against cancer, but in recent years the use of immunotherapeutic approaches has gained prominence as the fourth treatment modality in cancer patients. In this approach, a patient's innate and adaptive immune systems are activated to achieve clearance of occult cancerous cells. In this review, we discuss the preclinical and clinical immunotherapeutic (e.g., immunoadjuvants (in-situ vaccines, oncolytic viruses, CXC antagonists, device activated agents), organic and inorganic nanoparticles, and checkpoint blockade) that are under investigation for cancer therapy and diagnostics. Additionally, the innovations in imaging of immune cells for tracking therapeutic responses and limitations (e.g., toxicity, inefficient immunomodulation, etc.) are described. Existing data suggest that if immune therapy is optimized, it can be a real and potentially paradigm-shifting cancer treatment frontier.

A “turn-on” fluorescent probe for highly selective discrimination of hypochlorite (ClO−) from oxidants including dichromates (Cr2O72−) in aqueous media

A carbazole-based probe was synthesized and found to fluoresce (λ_em,max = 440 nm) in the presence of hypochlorite.

A novel rhodamine-based fluorescent probe for selective detection of ClO– and its application in living cell imaging

A novel fluorescent rhodamine-based probe L for selective responding to ClO– has been synthesized and characterized. The spectroscopy showed that probe L can detect ClO– in aqueous solution without interaction with other interfering ions, and the detection is also evident by the colour change from colourless to reddish purple under white light. The remarkable fluorescence enhancement showed the high selectivity and sensitivity of probe L for the detection of ClO–. Furthermore, probe L was applied to intracellular fluorescent imaging of HeLa cells treated with ClO– and MTT assay showed nontoxicity in living cells.

Rhodol Derivatives as Selective Fluorescent Probes for the Detection of HgII Ions and the Bioimaging of Hypochlorous Acid

Two sensors, 1 with a spirolactone group and 2 with a spirolactam group containing a phenyl isothiocyanate moiety, based on rhodol, were designed and synthesized in order to obtain materials with excellent optical properties for the detection of environmentally and biologically important Hg2+ and hypochlorous acid (HClO) ions. The crystal structure of 1 revealed two moieties, a rhodamine-like portion with a spirolactone and a fluorescein-like portion without a spirolactone. In the absence of analyte, 1 produced an optical output with a maximum absorption and emission at 475 and 570 nm, respectively, which was attributed to the fluorescein-like moiety without a spirolactone. In contrast, the rhodamine-like moiety containing a spirolactone was activated by the addition of H+ or Hg2+ ions, and 1 yielded new absorption and emission peaks at 530 and 612 nm, respectively. Further functionalization with a phenyl isothiocyanate group afforded 2, a fluorescent probe for HClO. High selectivity and sensitivity towards the hypochlorite ion were anticipated, owing to the stoichiometric and irreversible formation of a thiosemicarbazide group, which led to dramatic fluorescence responses. With good functionality at physiological pH, probe 2 was successfully used to image HClO in HeLa cells.