Search

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.

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.

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.

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 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 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 (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.