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Psoriasis is a chronic inflammatory skin disease that can significantly impact the quality of human life. Various drug treatments are available; however, due to their long-term severe side effects the usage of these drugs is limited. Photodynamic therapy (PDT) has been clinically approved for skin diseases due to its non-invasive nature. We present novel NNO-tridentate vanadium(IV) complexes used in PDT for anti-inflammatory effects in an imiquimod-induced psoriasis-like skin disease mouse model. The vanadium(IV) complexes (1-4) were synthesized using the NNO-tridentate ligand with a benzo[

Aggregation-induced emission (AIE)-active switchable [2]rotaxane TR2 with two different molecular stations and arm-terminated TPE units at both ends, and their derivatives were synthesized by means of threading, followed by the stoppering tactic via click chemistry. The AIE behavior of thread A1 and [2]rotaxanes (TR1, TR2, and TR3) in CH3CN were activated by tuning water fractions (fw), which induced the development of various well-defined nanostructures including spheres, nanorods, truncated cubes, and nanocubes via the self-assembly of scaffolds. These AIE changes and distinct nanostructures formation verify that the reported analogous rotaxanes were controlled by the shuttling movements of the macrocycle along with wide ranges of multi-non-covalent interactions. The anion-templated construction of [2]rotaxane TR2 with a high level of structurally complex design always encounters more challenging tasks. Evidently, the key to the design involved encoding flexible arms on both triazolium motifs, and exhibited an impressive selectivity and sensitivity (with a detection limit of 0.20 μM) towards the complementary H2PO4− ion species. The specific mechanical molecular motion and host–guest interactions of mechanically interlocked molecules (MIMs) were also further explored by quantum mechanical calculations. Importantly, the AIE changes of [2]rotaxanes TR1, TR2, and TR3 were further supported by their bioimaging applications and specifically, [2]rotaxane TR2 could be applied to in vitro imaging with H2PO4− at subcellular levels. This flexible multi-component synthetic strategy affords access to the systematic tuning of molecular structures and self-assembled architectures, and it will inspire further studies on the self-assembly of TPE-containing MIMs for materials science and biological applications.

Cancer has become one of the major diseases of human health around the world. Conventional antitumor drugs cannot specifically target cancers and result in serious side effects. To achieve better therapy, innovative functional drug delivery platforms that will aid specific targeting for cancer cells need to be developed. In this study, transferrin (Tf), which can target cancer cells, is covalently anchored onto the surface of MSNPs via disulfide linkage, which is used for glutathione-triggered intracellular drug release in tumor cells. The successful functionalization of redox-responsive MSNPs is confirmed by using BET/BJH, TEM, TGA, NMR, and FT-IR (BET, Brunauer-Emmett-Teller; BJH, Barrett-Joyner-Halenda). In addition, polyethylene glycol (PEG) is further grafted onto the surface of MSNPs to improve the biocompatibility and stability under physiological conditions for longer blood circulation. Our

Cancer has become a major cause of human death in many countries. Generally, chemotherapy is the main treatment for cancer, but it may kill both cancerous cells as well as normal cells that cause serious side effects in the patient due to lack of specific targeting for cancerous cells. In order to achieve better efficiency in the cancer treatment, the development of targeted drug delivery platform has been a goal for a long time. Herein, we constructed folic acid decorated azide functionalized biocompatible mesoporous silica nanoparticles (MSNPs) to target tumor cells through folate receptor (FR), a widely expressed receptor in cancer cells. In colon and ovarian cancer cells, high endogenous H2S levels are found. They can be used as a trigger for the azide reduction, which leads to the cleavage of ester linkage and results in DOX release from MSNP nanocarriers. Additionally, confocal cell images of HCT-116, HT-29, A2780, SKOV3, and HeLa cells treated with nanoparticles revealed an effective internalizatio...

Luminescent cysteamine-modified nanodiamond particles (ND-Cys) have been reported in surface-mediated energy transfer, cell imaging, and metal-ion recognition studies. In normalized photoluminescence (PL) spectral studies, the emission maxima of ND-Cys (at 50 µg/mL in water) was fixed at 438 nm at 350 nm excitation, producing a blue emission with a quantum yield (Φ) of 0.13. In the dispersion range of 0–800 µg/mL, ND-Cys exhibited agglomeration-induced energy transfer via red shifting of the PL peak from 438 nm to 451 nm. Analogous to PL studies, Raman interrogations also established the agglomeration and fixed the saturation limit to 500 µg/mL in water. The low toxicity and biocompatibility of ND-Cys were demonstrated using methyl thiazolyl tetrazolium assay and time-dependent HeLa cell imaging. Subsequently, the Hg2+ selectivity by ND-Cys was revealed by an intense fluorescence peak shift from 440 nm to 463 nm. Fluorescence studies indicated that the detection limit of Hg2+ ions approximated 153 nM. Fourier-transform infrared and X-ray photoelectron spectroscopy (XPS) analyses supported the binding between free thiol ( SH) and amide ( C O and NH) groups of ND-Cys to Hg2+. The Hg2+-induced agglomeration and surface graphitization were successfully confirmed by X-ray powder diffraction, XPS, Raman, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, and zeta potential analyses. Effective detection of Hg2+ ions by ND-Cys was validated through HeLa cell imaging at shortened time intervals.

Hypochlorous acid has played several functions in the biological system. However, excess HOCl can cause damage to biomolecules and result in some diseases. Accordingly, a new fluorescent probe, BSP, has been developed for fast recognition of HOCl through the HOCl-induced oxidation of methyl phenyl sulfide to sulfoxide. The reaction of BSP with HOCl caused a 22-fold fluorescence enhancement (quantum yield increase from 0.006 to 0.133). The detection limit of HOCl is found to be 30 nM (S/N = 3). The fluorescence enhancement is due to the suppression of the photo-induced electron transfer from the methyl phenyl sulfide moiety to BODIPY. Eventually, the cellular fluorescence imaging experiment showed that BSP could be effectively used for monitoring HOCl in living cells.

Clinical cases of allergic reaction that are due to excipients containing polyethylene glycol (PEG), a hydrophilic molecule commonly used in drug/vaccine formulations, has attracted much attention in recent years. In order to develop PEG-free adjuvants, we investigated the feasibility of natural ingredients in the human body such as hyaluronic acid in the form of hyaluronic acid-glycine cholesterol (HACH) conjugate as an excipient for vaccine formulation. Interestingly, HACH grafted with ~13 wt.% cholesterol has good water dispersity and can serve as an emulsifier to stabilize the squalene/water interfaces, yielding a milky white and isotropic emulsion (SQ@HACH) after being passed through a high-shear microfluidizer. Our results show that SQ@HACH particles possessed a unimodal average hydrodynamic diameter of approximately 190 nm measured by dynamic light scattering and exhibited good stability upon storage at 4 °C and 37 °C for over 20 weeks. The results of immunogenicity using a mouse model with ovalbumin (OVA) as the antigen revealed that SQ@HACH significantly enhanced antigen-specific immune responses, including the polarization of IgG antibodies, the cytokine secretions of T cells, and enhancement of cytotoxic T lymphocyte (CTL) activation. Moreover, SQ@HACH revealed lower local inflammation and rapidly absorbing properties compared with AlPO4 after intramuscular injection in vivo, indicating the potential functions of the HA-derived conjugate as an excipient in vaccine formulations for enhancement of T cell-mediated immunity.

Dry eye syndrome (DES) is a common ocular disease worldwide. Currently, anti-inflammatory agents and immunosuppressive drugs, such as cyclosporine A, have been widely used to treat this chronic condition. However, the multifactorial etiology of DES, poor tolerance, low bioavailability, and prolonged treatment to response time have limited their usage. In this study, nimesulide, a cyclooxygenase (COX)-2 selective inhibitor, was conjugated with hyaluronic acid (HA), and the HA-nimesulide conjugates were expected to increase the solubility and biocompatibility for alleviating the DES in the benzalkonium chloride (BAC)-induced goblet cell-loss dry eye model. The therapeutic efficacy of HA-nimesulide was assessed using fluorescein staining, goblet cell density by conjunctival impression cytology, and histology and immunohistochemistry of corneal tissues. Compared to commercial artificial tears and Restasis®, the HA-nimesulide conjugates could promote goblet cell recovery and enhance the regeneration of the corneal epithelium. Importantly, immunofluorescent staining studies demonstrated that the HA-nimesulide conjugates could decrease the number of infiltrating CD11b-positive cells after two weeks of topical application. In the anti-inflammatory test, the HA-nimesulide conjugates could inhibit the production of pro-inflammatory cytokines and prostaglandin E2 (PGE2) in the lipopolysaccharide (LPS)-stimulated Raw 264.7 cell model. In conclusion, we demonstrated that HA-nimesulide conjugates had anti-inflammatory activity, and promoted goblet cell recovery and corneal epithelium regeneration when used as topical eye drops, accordingly, the HA-nimesulide conjugates could potentially be effective for the treatment of DES.

A triple action chemosensor (R1) bearing a rhodamine and thiophene moiety was synthesized by a simple condensation reaction. The sensing behaviour and selectivity of the synthesized chemosensor toward metal ions were studied by UV-Vis and fluorescence spectroscopy. The chemosensor recognized Cu2+ and Cr3+ ions with significant changes in UV-Vis absorbance and fluorescence intensity. The results showed that Cr3+ induced greater fluorescence enhancement whereas Cu2+ ions bound strongly with the receptor by showing a strong absorption band at 554 nm but with weak fluorescence. A visible colour change was observed by the addition of Cu2+ and that colour change is due to the opening of the spirolactam ring triggered by the addition of Cu2+ ions. Job's plot analysis indicated a 1 : 2 and 1 : 1 binding stoichiometry between the chemosensor and Cr3+/Cu2+. Subsequently, the R1 - Cu2+ complex chemosensor was employed to detect CN- in the presence of different anions, such as F-, Cl-, Br-, I-, AcO-, H2PO4-, HSO4-, NO3- and -OH. In addition, the live cell imaging of HeLa cells using R1 and Cr3+ was demonstrated successfully.

Citrate based sol–gel method is used to synthesize Gd₂O₃:RE³⁺ and GdAlO₃:RE³⁺ (RE = Eu, Dy) phosphors. In the present work, the phosphors are characterized using the techniques like X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS) and photoluminescence spectroscopy (PL). Fluorescence confocal microscopy reveals the potential usage of phosphors in biological medium for biolabeling application. XRD patterns confirm the phase purity of Gd₂O₃ and GdAlO₃. The crystallite size and lattice parameters are estimated from XRD result. FTIR spectra are used to investigate the functional group present in the phosphor. The optical emission properties imply that the emission peak positions on Eu³⁺ or Dy³⁺ ion are size and host independent. Finally, RAW 264.7 macrophages cell line is used to test the bioimaging performance of the phosphors.

A rhodamine-B based chemosensor with diphenylselenium, RhoSe, has been synthesized, and its detection behavior towards various metal ions is studied via UV/Vis and fluorescence spectroscopy. RhoSe shows a selective response to Hg2+ in CH3OH/H2O (v/v = 9 : 1) solutions over other metal ions. After addition of Hg2+, the solution of RhoSe displays an obvious color change from colorless to pink and a significant, 48-fold fluorescence enhancement. The color change and fluorescence enhancement are attributed to the ring-opening of the spirolactam in the rhodamine fluorophore, which is induced by Hg2+ binding. The binding ratio of RhoSe–Hg2+ was determined by a Job plot as a 1 : 1 ratio, and the effective pH range for Hg2+ detection was 4.0–10. Importantly, the reversibility of the RhoSe–Hg2+ complex was observed through the addition of Na2S. For practical applications, the strip method was utilized to detect Hg2+ in water/methanol solution. In addition, confocal fluorescence microscopy experiments demonstrated that RhoSe is an effective fluorescent probe for Hg2+ detection in vitro and in vivo.

Near-infrared (NIR)-based nanomaterials that provide efficient tumor ablation for cancer therapy have been reported. However, the issues of biocompatibility of metals or ions in inorganic nanoparticles systems such as copper and gold nanoparticles are still a matter of concern. In this study, we developed a facile and ligand-assisted co-precipitation method to synthesize biocompatible iron oxide (IO) nanocrystals with NIR absorption that provided T2-weighted magnetic resonance (MR) images and photothermal ablation characteristics suitable for cancer theranostics. Our results showed that 150-nm particles can be synthesized and optimized by using different amounts of ligand. NIR-IO nanocrystals of this size showed high photothermal conversion efficiency (21.2%) and T2-weighted MR contrast (transverse relaxivity value approximately 141 S-1 mM-1). The NIR-IO nanocrystals showed no cytotoxicity in HT-29 colorectal cancer cells without irradiation, whereas the viability of cells that received NIR-IO nanocrystals decreased significantly after 808-nm laser irradiation. The mechanism of cell death may involve alterations in protein secondary structure and membrane permeability. For in vivo studies, 4-fold enhanced tumor accumulation was significantly observed of NIR-IO nanocrystals with a magnetic field (MF) application, resulting in a 3-fold higher T2-weighted MR signal than that produced by a commercial T2-weighted MR contrast agent (Resovist®) and excellent photothermal efficacy (approximately 53 °C) for cancer treatment. The innovative NIR-IO nanocrystals showed excellent biocompatibility and have great potential as a theranostic agent against cancer.

A new coumarin-based fluorescent probe CAA containing an acrylamide group has been designed and synthesized for the detection of biothiols. The probe CAA shows high selectivity and sensitivity for cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) over other amino acids. A fluorescence turn-on response is induced by a Michael-type reaction. It shows a highly sensitive fluorescence emission to Cys, Hcy, and GSH, with detection limits of 192 nM for Cys, 158 nM for Hcy, and 155 nM for GSH (S/N = 3). Furthermore, confocal fluorescence microscopy imaging using RAW264.7 macrophages demonstrates that CAA can be an effective fluorescent probe for thiols in living cells.

Novel fluorogenic receptors S1–S4 (imidazo anthraquinone derivatives) were synthesized from o-substituted benzaldehyde and 1,2-diaminoanthraquinone and characterised with various spectroanalytical techniques. In the case of S1, the selectivity towards cyanide ions with turn-on fluorescence output among other anions, due to the inhibition of the twisted intramolecular charge transfer (TICT) mechanism. The effect of substitution was successfully compared with sensing studies of S2–S4. S1 showed a good binding constant with a 1 : 1 stoichiometric ratio and micromolar detection limit. The sensing behaviour was further supported by 1H NMR titration, TD-DFT calculations and lifetime measurement studies. S1 was applied for the bio-imaging of the cell line RAW264.7 and successfully sensed cyanide ions under physiological conditions.

The synthesis and characterization of an NAD(P)H:quinone oxidoreductase 1 (NQO1) enzyme responsive nanocarrier based on mesoporous silica nanoparticles (MSNPs) for on-command delivery applications has been described in this paper. Gatekeeping of MSNPs is achieved by the integration of mechanically interlocked rotaxane nanovalves on the surface of MSNPs. The rotaxane nanovalve system is composed of a linear stalk anchoring on the surface of MSNPs, an α-cyclodextrin ring that encircles it and locks the payload “cargo” molecules in the mesopores, and a benzoquinone stopper incorporated at the end of the stalk. The gate opening and controlled release of the cargo are triggered by cleavage of the benzoquinone stopper using an endogenous NQO1 enzyme. In addition to having efficient drug loading and controlled release mechanisms, this smart biocompatible carrier system showed obvious uptake and consequent release of the drug in tumor cells, could selectively induce the tumor cell death and enhance the capability of inhibition of tumor growth in vivo. The controlled drug delivery system demonstrated its use as a potential theranostic material.

A sensitive and selective colorimetric Cr3+ detection method was developed by using O-phospho- l -serine dithiocarbamic acid (PSDTC) functionalized gold nanoparticles (PSDTC-AuNPs). The presence of Cr3+ immediately induced aggregation of PSDTC-AuNPs, yielding a color change from red to blue. This Cr3+-induced aggregation of PSDTC-AuNPs was monitored by bare eye and UV–vis spectroscopy. The SPR absorbance (651 nm) of the reaction between PSDTC-AuNPs and Cr3+ shows a good linearity in the Cr3+ concentration with a low detection limit 4.2 nM (S/N = 3). PSDTC-AuNPs showed excellent selectivity toward Cr3+ compared to other metal ions Ag+, Al3+, Ca2+, Cd2+, Co2+, Cu2+, Fe2+, Fe3+, Hg2+, Mg2+, Mn2+, Ni2+, Pb2+, and Zn2+. Optimal detection of Cr3+ was achieved over a pH range from 5 to 10. In addition, PSDTC-AuNPs were applied to detect Cr3+ in lake water, showing low interference.

Nanodiamonds were modified such that they carry thiol groups (ND-thiol). Gold nanoparticles were reacted with ND-thiol to obtain a highly stable conjugate of the type ND@AuNPs. Both ND-thiol and the ND@AuNPs were characterized by SEM, TEM, AFM, DLS, zeta potential, XPS, XRD, UV-Vis, Raman, FTIR and cytotoxicity studies. Their biocompatibility was confirmed via an MTT assay with HeLa cells. At a pH value of 6, the ND@AuNPs represent a colorimetric probe that can be used to selectively detect the illegally used β-adrenergic drug clenbuterol (CLB) and the pollutant chromium(III). Detection can be performed visually by monitoring the color change from wine red to purple blue, or by colorimetric measurement of the so-called SPR peaks at 651 and 710 nm. The color changes are due to aggregation, and this is confirmed by TEM and DLS data. The involvement of surface functional groups that assist in analyte recognition was verified by FTIR. The detection limits are 0.49 nM for CLB, and 0.37 nM for Cr(III). The ND@AuNPs were successfully applied to the determination of Cr(III) and CLB in spiked human urine samples. Notably, the low interference by other ions in the detection of Cr(III) in tap and lake water is confirmed by ICP-MS analyses. Graphical abstract Nanodiamonds carrying thiol groups (ND-Thiol) were conjugated to gold nanoparticles, and the resulting ND@AuNPs are shown to be viable probes for the colorimetric detection of sub-nanomolar levels of clenbuterol (CLB) and Cr(III) ions, with demonstrated applicability to real water and urine samples.

Photodynamic therapy (PDT) is a promising and minimally invasive method for the treatment of superficial diseases, and photosensitizers with high phototoxicity indices (defined as (IC50dark )/(IC50irradiation )) are essential for the development of ideal photosensitizing properties for this technology. Herein, we report a series of photocytotoxic copper(II) complexes [Cu(R QYMP)(dppn)] (R QYMP=N,N,O-tridentate Schiff-base derivatives, dppn=benzo[i]dipyrido[3,2-a;2',3'-c]phenazine), the structures of which have been confirmed by mass spectrometry and FTIR spectroscopy. X-ray crystallography revealed that the CuN4 O core of the [Cu(cumyl QYMP)(dppn)](ClO4 ) complex (3) has a distorted square-pyramidal geometry. Phototoxicity indices of 329 against human squamous cell carcinoma (SCC15) and 296 against basal cell carcinoma (BCC) cell lines have been determined with [Cu(3-OMe QYMP)(dppn)](ClO4 ) (4). This can be attributed to the formation of reactive oxygen species, cell apoptosis, and caspase-3 activation, indicating high potential of complex 4 as a photosensitizer candidate in PDT. Thus, copper complexes bearing suitable Schiff-base ligands with a dppn co-ligand may be considered for the design of efficient metal-based anticancer agents for PDT.

A BODIPY-based fluorescent probe, HBP, was developed for the detection of hypochlorous acid based on the specific hypochlorous acid-promoted oxidative intramolecular cyclization of heterocyclic hydrazone in response to the amount of HOCl. The reaction is accompanied by a 41-fold increase in the fluorescent quantum yield (from 0.004 to 0.164). The fluorescence intensity of the reaction between HOCl and HBP is linear in the HOCl concentration range of 1–8 μM with a detection limit of 2.4 nM (S/N = 3). Confocal fluorescence microscopy imaging using RAW264.7 cells showed that the new probe HBP could be used as an effective fluorescent probe for detecting HOCl in living cells.

A new dual chemosensor (Z)-2-(anthracen-9-ylmethylene)-N-phenylhydrazinecarbothioamide R1 was synthesized by incorporating a thiourea derivative as a binding unit and an anthracene group as a fluorescence signalling unit. R1 selectively binds with Cu2+ and Hg2+ ions in aqueous medium. R1 exhibits highly selective recognition towards F− ion and picric acid in organic medium. Fluorescence quenching was observed in case of R1 with Cu2+ and Hg2+ ions over commonly coexistent metal ions. Furthermore, fluorescence imaging experiments of Cu2+ and Hg2+ ions in living RAW 264.7 cells demonstrate its value of practical applications in biological systems.

Heterocyclic ring based R 1 –R 3 have been synthesized from the simple condensation method. R 1 –R 3 exhibit highly selective and sensitive recognition towards transition metal ions in an aqueous medium via visual color change and were further confirmed by UV–vis and fluorescent spectroscopic methods. Fluorescent turn on and turn off behavior was observed for receptors tested with transition metal ions. The interaction of transition metal ions and receptors R 1 –R 3 was confirmed to adopt 1:1 binding stoichiometry. Micromolar detection limit was found for R 1 –R 3 with metal ions. DFT theoretical calculations were employed to understand the sensing mechanism of the sensors towards the metal ions. R 1 and R 2 were also successfully demonstrated as a fluorescent probe for detecting Cu 2+ ions in living cells.

A BODIPY-based fluorescent chemosensor 1 selectively detects Zn2+ by significant fluorescence enhancement. The binding ratio of the 1-Zn2+ complex was determined from a Job plot to be 1:1. The binding constant (Ka) of Zn2+ binding to chemosensor 1 was found to be 5.9 × 104 M−1, with a detection limit of 0.59 μM. Furthermore, the 1-Zn2+ complex can specifically detect pyrophosphate (PPi) through fluorescence quenching. The detection limit for detecting PPi was found to be approximately 17.5 μM. Fluorescence microscopy imaging using RAW264.7 cells showed that chemosensor 1 can be used as an effective fluorescent probe for detecting Zn2+ and PPi in living cells.

A dipodal N-acyl hydrazone receptor (R1) was synthesized in a single step, and utilized as a test probe for the selective sensing of metal ions as well as anions. Upon the exposure to various metal ions, R1 displays rapid colorimetric and absorption changes in the presence of Co2+, Ni2+, Cu2+ and Zn2+ ions. However, R1 shows a selective fluorescence response only in the presence of Zn2+ ions and no other metal ions showed obvious changes. In particular, zinc acetate showed higher sensitivity over other zinc sources. Upon the binding of Zn2+ ions with R1, the colorless solution changed into fluorescent yellow color accompanied by the conversion of the non-fluorescence nature into the highly fluorescence nature. The in situ formed R1–Zn2+ complex was further explored for the reversible recognition of H2PO4− ions selectively over other anions such as F−, Cl−, Br−, AcO−, CN−, HSO4− and NO3− ions. A strong and enhanced emission at 502 nm and 534 nm corresponding to the R1–Zn2+ complex was quenched completely in the presence of H2PO4− ions. Relay recognition of different phosphates such as mono, di and tri basic phosphate ions was also tested. Furthermore, R1 has good cell permeability and could serve as a bioprobe in living cells for the intracellular uptake of Zn2+ and H2PO4− ions. Time dependent density functional (TDDFT) calculation has been performed to demonstrate the binding of Zn2+ ions with R1.

A boron dipyrromethene-based fluorescent probe, BODH, has been successfully developed for hypochlorous acid detection based on the HOCl-promoted oxidative removal of the CN bond in response to the amount of HOCl. The reaction is accompanied by a 6-fold increase in fluorescent quantum yield (from 0.05 to 0.29). The fluorescence intensity of the reaction between HOCl and BODH shows a good linearity in the HOCl concentration range of 1–25 μM with a low detection limit of 205 nM (S/N = 3). Confocal fluorescence microscopy imaging using RAW264.7 cells shows that the new probe, BODH, can be used as an effective fluorescent probe for the detection of HOCl in living cells.

A fluorescent probe (NBDTe) based on an NTe2 chelating motif has been developed for the highly selective and sensitive detection of Hg2+. Significant fluorescence enhancement was observed with the chemosensor NBDTe in the presence of Hg2+. Moreover, the metal ions Ag+, Al3+, Ca2+, Cd2+, Co2+, Cu2+, Cr3+, Fe2+, Fe3+, Hg2+, Mg2+, Mn2+, Ni2+, Pb2+, and Zn2+ produced only minor changes in the fluorescence values of the system. The association constant (Ka) of Hg2+ binding to the chemosensor NBDTe was found to be 3.81 × 103 M−1, with a detection limit of 4.2 μM. The maximum fluorescence enhancement caused by Hg2+ binding to the chemosensor NBDTe was observed over the pH range of 4.0–10.0. In addition, fluorescence microscopy experiments showed that the chemosensor NBDTe can be used as a fluorescent probe for detecting Hg2+ in living cells.

A fluorescent probe HCTe was developed for rapid detection of hypochlorous acid based on the specific HOCl-promoted oxidation of diphenyl telluride. The reaction is accompanied by an 82-fold increase in the fluorescence quantum yield (from 0.009 to 0.75). The fluorescence turn-on mechanism is achieved by the suppression of photoinduced electron transfer (PET) from the diphenyl telluride group to BODIPY. The fluorescence intensity of the reaction between HOCl and HCTe is linear in the HOCl concentration range of 1 to 10 μM with a detection limit of 41.3 nM (S/N = 3). In addition, confocal fluorescence microscopy imaging using RAW264.7 macrophages demonstrated that HCTe could be an efficient fluorescent probe for HOCl detection in living cells.

A simple pyrene-linked thiourea 1 has been synthesized and shown to act as a fluorescent and visual sensor for the detection of Cu2+ and Hg2+ ions. The sensor showed effective detection of Cu2+ and Hg2+ at a low detection limit. Receptor 1 has been successfully applied in the fluorescence imaging of Cu2+ and Hg2+ ions in living cells. Receptor 1 also selectively detects picric acid via both color change and fluorescence change.

Chemosensor 1 detects only the presence of Cu2+ ions among other metal ions through a color change from pale yellow to green. 1 functions as a tridentate ligand that binds Cu2+ ions through three amine nitrogen functional groups. In the presence of Cu2+, 1 provided significant color change, while Ag+, Ca2+, Cd2+, Co2+, Fe2+, Fe3+, Hg2+, Mn2+, Ni2+, Pb2+, and Zn2+ metal ions produced only minor changes in UV–vis absorption. The association constant (Ka) for Cu2+ binding to 1 had a value of 1.307 × 103 M−1. The maximum absorption change induced by Cu2+ binding to the chemosensor was observed over the pH range 6.0–10.0. A new band observed at 600 nm indicated the formation of deprotonated 1–Cu2+ complexes.

A new dipyrromethene derivative ( DP1 ) exhibits an enhanced fluorescence in the presence of Zn 2+ ions and a high selectivity for Zn 2+ ions over competing metal ions in methanol; Ag + , Ca 2+ , Co 2+ , Cr 3+ , Fe 2+ , Fe 3+ , Hg 2+ , K + , Mg 2+ , Mn 2+ , Ni 2+ , and Pb 2+ produced only minor changes in the fluorescence of DP1 . The binding ratio of the DP1 –Zn 2+ complexes was determined from a Job plot to be 1:1. The binding constant ( K a ) of Zn 2+ binding to DP1 was found to be 6.12 × 10 4 M −1 , with a detection limit of 0.236 μM. Fluorescence microscopy imaging using RAW264.7 cells showed that DP1 could be used as an effective fluorescent probe for detecting Zn 2+ in living cells.

A triple action chemosensor (R1) bearing a rhodamine and thiophene moiety was synthesized by a simple condensation reaction. The sensing behaviour and selectivity of the synthesized chemosensor toward metal ions were studied by UV-Vis and fluorescence spectroscopy. The chemosensor recognized Cu

A fluorescent probe (FS) based on a fluoride-specific desilylation reaction has been developed for a highly selective and sensitive detection of F−. In the presence of F−, the probe FS provided significant green fluorescence enhancement, while other anions produced only minor changes in fluorescence intensity. The probe FS has a limit of detection of 1.45 μM, which is reasonable for the detection of micromolar concentrations of F− ions. The maximum fluorescence enhancement induced by F− in the probe was observed over the pH range 7–10. Moreover, fluorescence microscopy imaging using mouse leukaemic monocyte macrophage showed that the probe FS could be an efficient fluorescent probe for F− ions in living cells.