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We report a novel, reversible, cell-permeable, pH-sensor, TRapH. TRapH afforded a pH-sensitive ratiometric emission response in the pH range ~3-6, enabling imaging and quantification of pH in living cells. The biological-applicability of TRapH was illustrated via live-tracking of intracellular pH dynamics in living mammalian cells induced by a synthetic H + -transporter., (© 2024 The Authors. ChemBioChem published by Wiley-VCH GmbH.)

The impacts of dimethylation of 4-Amino-1,8-Naphthalimide (ANI) on its photophysical properties are reported. The resulting 4-DiMe-ANI displays completely different fluorescence properties, conferring it ability to selectively label lipid droplets in living cells. A comprehensive photophysical study revealed that this selectivity arises from an Internal Charge Transfer favored in lipophilic media to the detriment of a non-emissive TICT in more polar media. This results in a very high "LDs/Cytosol" signal ratio, enabling LDs to be imaged with an excellent signal-to-noise ratio, and positioning its performance above that of the BODIPY 493/503 commonly used to image LDs., (© 2024 The Authors. ChemBioChem published by Wiley-VCH GmbH.)

A novel series of 1,8-naphthalimide piperazinamide based benzenesulfonamides derivatives were designed and synthesized as carbonic anhydrase IX (CA IX) inhibitors and ferroptosis inducers for the treatment of triple-negative breast cancer (TNBC). The representative compound 9o exhibited more potent inhibitory activity and selective against CA IX over off-target CA II, compared with positive control SLC-0111. Molecular docking study was also performed to gain insights into the binding interactions of 9o in the binding pocket of CAIX. Moreover, compound 9o exhibited superior antitumor activities against breast cancer cells under hypoxia than that of normoxia conditions. Mechanism studies revealed that compound 9o could act as DNA intercalator and effectively suppressed cell migration, arrested the cell cycle at G1/S phase and induced apoptosis in MDA-MB-231 cells, while inducing ferroptosis accompanied by the dissipation of MMP and the elevation intracellular levels of ROS. Notably, in vivo studies demonstrated that 9o effectively inhibited tumor growth and metastasis in a highly metastatic murine breast cancer 4 T1 xenograft model. Taken together, this study suggests that compound 9o represents a potent and selective CA IX inhibitor and ferroptosis inducer for the treatment of TNBC., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Copper(II) complexes are very promising candidates for platinum-based anticancer agents. Herein, three Cu (II) complexes (1-3) containing 1,8-naphthalimide ligands were synthesized and characterized by FT-IR, elemental analysis, ESI-MS and single crystal X-ray diffraction (complex 3). In addition, a control compound (complex 4) without 1,8-naphthalimide ligand was synthesized and characterized. The in vitro anticancer activity of the synthesized complexes against five cancer cell lines and one normal cell line was evaluated by MTS assay. The results displayed the antitumor activity of complexes 1-3 was controlled by the aliphatic chain length of ligands, their cytotoxicity was in the order 3 > 2 > 1, giving the IC 50 values ranging from 2.874 ± 0.155 μM to 31.47 ± 0.29 μM against five cancer cell lines. Complex 4 showed less activity in comparison with complex 1-3. Notably, complexes 1-3 displayed much higher selectivity (SI = 2.65 to 10.16) compared to complex 4 (SI = 1.0), indicated that the introduction of 1,8-naphthalimide group not only increased the activity of this series of compounds but also enhanced their specific selectivity to cancer cells. Compound 3 induced apoptosis in cancer cells and blocked the S-phase and G2/M of cancer cells. The interaction with DNA of complexes 3 and 4 was studied by UV/Vis spectroscopic titrations, competitive DNA-binding experiment, viscometry and CD spectra. The results showed that complex 3 interacted with DNA in an intercalating mode, but the interaction mode of compound 4 with DNA was electrostatic interaction., Competing Interests: Declaration of competing interest The authors declare that they do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted., (Copyright © 2024 Elsevier Inc. All rights reserved.)

A series of naphthalimide dyes (TRNATR, MOTNAMOT, MPNAMP, TYNATY, PNAP and IZNAIZ) were designed and synthesized by altering the side chains of the naphthalimide. Without the need for ER-targeting groups, the first five dyes were found to specifically target the ER, likely due to their well-suited lipophilic properties. Furthermore, TRNATR and TYNATY were proven effective for studying ER stress, showing promise in tracking ER autophagy in living cells triggered by tunicamycin and nutritional starvation.

In the present study, naphthalimide-pyrazole-benzothiazole based fluorescent analogs were synthesized by substituting different primary and secondary amines on the naphthalimide nucleus and were evaluated for their sensitivity and selectivity towards serum albumin. Among various synthesized analogues compound 25 showed the most significant change with serum albumin and was further studied for selective detection and mode of interaction with serum albumin. Here, we compared the binding interaction of fluorescent probe 25 for variation/detection of two 76 % structurally resembling proteins HSA and BSA, by spectroscopic experiments. The compound shows more selectivity for HSA and BSA with a higher binding constant and evident visible change in the emission spectra of two serum albumins among different bioanalytes. The mode of interaction of 25 with human serum albumin and bovine serum albumin was investigated by FT-IR, circular dichroism, and DLS techniques to find out the change in the microenvironment and variation in the structure of serum albumin proteins. Higher binding affinity and specific selectivity of 25 with a limit of detection of 0.69 μM and 1.4 μM towards HSA and BSA compared to other bioanalytes make it a significant fluorescent probe for quantitatively detecting serum albumins at the very early stage of many fatal diseases., (© 2024 Wiley-VCH GmbH.)

Human cytochrome P450 1B1 enzyme (hCYP1B1), a member of hCYP1 subfamily, plays a crucial role in multiple diseases by participating in many metabolic pathways. Although a suite of potent hCYP1B1 inhibitors have been previously reported, most of them also act as aryl hydrocarbon receptor (AhR) agonists that can up-regulate the expression of hCYP1B1 and then counteract their inhibitory potential in living systems. This study aimed to develop novel efficacious hCYP1B1 inhibitors that worked well in living cells but without AhR agonist effects. For these purposes, a series of 1,8-naphthalimide derivatives were designed and synthesized, and their structure-activity relationships (SAR) as hCYP1B1 inhibitors were analyzed. Following three rounds SAR studies, several potent hCYP1B1 inhibitors were discovered, among which compound 3n was selected for further investigations owing to its extremely potent anti-hCYP1B1 activity (IC 50  = 0.040 nM) and its blocking AhR transcription activity in living cells. Inhibition kinetic analyses showed that 3n potently inhibited hCYP1B1 via a mix inhibition manner, showing a K i value of 21.71 pM. Docking simulations suggested that introducing a pyrimidine moiety to the hit compound (1d) facilitated 3n to form two strong interactions with hCYP1B1/heme, viz., the C-Br⋯π halogen bond and the N-Fe coordination bond. Further investigations demonstrated that 3n (5 μM) could significantly reverse the paclitaxel (PTX) resistance in H460/PTX cells, evidenced by the dramatically reduced IC 50 values, from 632.6 nM (PTX alone) to 100.8 nM (PTX plus 3n). Collectively, this study devised a highly potent hCYP1B1 inhibitor (3n) without AhR agonist effect, which offered a promising drug candidate for overcoming hCYP1B1-associated drug resistance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

A tumor-targeting fluorescent probe has attracted increasing interest in fluorescent imaging for the noninvasive detection of cancers in recent years. Sulfonamide-containing naphthalimide derivatives (SN-2NI, SD-NI) were synthesized by the incorporation of N-butyl-4-ethyldiamino-1,8-naphthalene imide (NI) into sulfonamide (SN) and sulfadiazine (SD) as the tumor-targeting groups, respectively. These derivatives were further characterized by mass spectrometry (MS), nuclear magnetic resonance spectroscopy ( 1 H NMR), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV), and a fluorescence assay. In vitro properties, including cell cytotoxicity and the cell uptake of tumor cells, were also evaluated. Sulfonamide-containing naphthalimide derivatives possessed low cell cytotoxicity to B16F10 melanoma cells. Moreover, SN-2NI and SD-NI can be taken up highly by B16F10 cells and then achieve good green fluorescent images in B16F10 cells. Therefore, sulfonamide-containing naphthalimide derivatives can be considered to be the potential probes used to target fluorescent imaging in tumors.

Strigolactones (SLs) have potential to be used in sustainable agriculture to mitigate various stresses that plants have to deal with. The natural SLs, as well as the synthetic analogs, are difficult to obtain in sufficient amounts for practical applications. At the same time, fluorescent SLs would be useful for the mechanistic understanding of their effects based on bio-imaging or spectroscopic techniques. In this study, new fluorescent SL mimics containing a substituted 1,8-naphthalimide ring system connected through an ether link to a bioactive furan-2-one moiety were prepared. The structural, spectroscopic, and biological activity of the new SL mimics on phytopathogens were investigated and compared with previously synthetized fluorescent SL mimics. The chemical group at the C-6 position of the naphthalimide ring influences the fluorescence parameters. All SL mimics showed effects similar to GR24 on phytopathogens, indicating their suitability for practical applications. The pattern of the biological activity depended on the fungal species, SL mimic and concentration, and hyphal order. This dependence is probably related to the specificity of each fungal receptor-SL mimic interaction, which will have to be analyzed in-depth. Based on the biological properties and spectroscopic particularities, one SL mimic could be a good candidate for microscopic and spectroscopic investigations.

Targeting polo-box domain (PBD) small molecule for polo-like kinase 1 (PLK1) inhibition is a viable alternative to target kinase domain (KD), which could avoid pan-selectivity and dose-limiting toxicity of ATP-competitive inhibitors. However, their efficacy in these settings is still low and inaccessible to clinical requirement. Herein, we utilized a structure-based high-throughput virtual screen to find novel chemical scaffold capable of inhibiting PLK1 via targeting PBD and identified an initial hit molecule compound 1a. Based on the lead compound 1a, a structural optimization approach was carried out and several series of derivatives with naphthalimide structural motif were synthesized. Compound 4Bb was identified as a new potent PLK1 inhibitor with a K D value of 0.29 μM. 4Bb could target PLK1 PBD to inhibit PLK1 activity and subsequently suppress the interaction of PLK1 with protein regulator of cytokinesis 1 (PRC1), finally leading to mitotic catastrophe in drug-resistant lung cancer cells. Furthermore, 4Bb could undergo nucleophilic substitution with the thiol group of glutathione (GSH) to disturb the redox homeostasis through exhausting GSH. By regulating cell cycle machinery and increasing cellular oxidative stress, 4Bb exhibited potent cytotoxicity to multiple cancer cells and drug-resistant cancer cells. Subcutaneous and oral administration of 4Bb could effectively inhibit the growth of drug-resistant tumors in vivo, doubling the survival time of tumor bearing mice without side effects in normal tissues. Thus, our study offers an orally-available, structurally-novel PLK1 inhibitor for drug-resistant lung cancer therapy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Here, we report the installation of 1,8-naphthalimide dyes in live cell imaging of plants. We developed a series of 1,8-naphthalimide-based probes that illuminate different subcellular compartments by altering their spectral characteristics. Simple infiltration of the probes into leaves rapidly visualized the structure of chloroplasts or the vacuole. We further demonstrated that these probes are applicable to monitor the organelle behaviors in an autophagy pathway.

Aim: The high incidence and prevalence of fungal infections call for new antifungal drugs. This work was to develop naphthalimide thiazoles as potential antifungal agents. Results & methodology: These compounds showed significant antifungal potency toward some tested fungi. Especially, naphthalimide thiazole 4h with excellent anti- Candida tropicalis efficacy possessed good hemolysis level, low toxicity and no obvious resistance. Deciphering the mechanism showed that 4h interacted with DNA and disrupted the antioxidant defense system of C. tropicalis . Compound 4h also triggered membrane depolarization, leakage of cytoplasmic contents and LDH inhibition. Simultaneously, 4h rendered metabolic inactivation and eradicated the formed biofilms of C. tropicalis . Conclusion: The multifaceted synergistic effect initiated by naphthalimide thiazoles is a reasonable treatment window for prospective development.

Histone deacetylase 8 (HDAC8) has been used as a therapeutic target for many cancers as it is highly expressed in neuroblastoma cells and breast cancer cells. HDAC8-selective fluorescent probes need to be urgently developed. Herein, two novel fluorescent probes, namely NP-C6-PCI and AM-C6-PCI , based on the conjugation of 1,8-naphthalimide with a highly selective inhibitor of HDAC8 ( PCI-34051 ) were reported. Compared with PCI-34051 ( K D = 6.25 × 10 -5 M), NP-C6-PCI ( K D = 8.05 × 10 -6 M) and AM-C6-PCI ( K D = 7.42 × 10 -6 M) showed great selectivity toward HDAC8. Two fluorescent probes exhibited high fluorescence intensity under λ ex = 450 nm and a large Stokes shift (100 nm). NP-C6-PCI was selected for cell and tissue imaging due to the similarity in the bioactivity of NP-C6-PCI with PCI-34051 . The ability of NP-C6-PCI to target imaging HDAC8 in SH-SY5Y and MDA-MB-231 tumor cells was demonstrated. Furthermore, NP-C6-PCI was applied to imaging SH-SY5Y tumor tissue slices to indicate the relative expression level of HDAC8. Therefore, this HDAC8-selective fluorescent probe can be expected for applications in HDAC8-targeted drug screening as well as in pathologic diagnoses.

The synthesis of fifteen luminescent bis-naphthalimide based Tröger's bases (TBNaps) derived from 4-amino-1,8-naphthalimide (4-Amino-Nap) precursors is described; these scaffolds possess α-amino acids, esters or di-peptides conjugated at the imide site and show minor fluorescence in aqueous solution while being highly emissive in organic solvents. The investigation shows that these TBNaps possessing ICT excited state properties are capable of generating either positive or negative solvatochromic effects in response to changes in polarity and/or the hydrogen bonding capabilities of the medium.

In recent years, fluorescent sensors have emerged as attractive imaging probes due to their distinct responses toward bio-relevant metal ions. However, the bioimaging application main barrier is the 'turn-off' response toward paramagnetic metal ions such as Cu 2+ under physiological conditions. Herein, we report a new sensor (2-methyl(4-bromo-N-ethylpiperazinyl-1,8-naphthalimido)-4-(1H-phenanthro[9,10-d]imidazole-2-yl) phenol)NPP with multifunctional (Naphthalimide, Piperazine, Phenanthroimidazole) units for fluorescent and colourimetric detection of Cu 2+ in an aqueous medium. Both absorption and fluorescence spectral titration strategies were used to monitor the Cu 2+ -sensing property of NPP. The NPP displays a weak emission at ca. 455 nm, which remarkably enhances (⁓3.2-fold) upon selective binding of Cu 2+ over a range of metal ions, including other paramagnetic metal ions (Mn 2+ , Fe 3+ , Co 2+ ). The stoichiometry, binding constant (K a ) and the LOD (limit of detection) of NPP toward Cu 2+ ions were found to be 1:1, 5.0 (± 0.2) × 10 4  M -1 and 6.5 (± 0.4) × 10 -7  M, respectively. We have also used NPP as a fluorescent probe to detect Cu 2+ in live (human cervical HeLa) cancer cells. The emission intensity of NPP was almost recovered in HeLa cells by incubating 'in situ' the derived Cu 2+ complex (NPP-Cu 2+ ) in the presence of a benchmark chelating agent such as EDTA (ethylenediaminetetraacetate). The fluorescent emission of NPP was reverted significantly in each cycle upon sequencial addition of Cu 2+ and EDTA to the NPP solution. Overall, NPP is a novel, simple, economic and portable sensor that can detect Cu 2+ in biological and environmental scenarios., (Copyright © 2021 Elsevier Inc. All rights reserved.)

A series of tripodal ferrocenyl bis-naphthalimide derivatives were synthesized and characterized. All of the bis-naphthalimide derivatives exhibited good DNA binding ability which was confirmed by ethidium bromide (EB) displacement experiment and ultraviolet (UV)-visible absorption titration. And the binding mode of these compounds was proved to be a hybrid binding mode by experiments. The cytotoxicity of synthesized compounds against 4 different human cancer cell lines (EC109, BGC823, SGC7901 and HEPG2) was evaluated by thiazolyl blue tetrazolium bromide (MTT) assay. All of the bis-naphthalimide derivatives exhibited good anticancer activity than the positive control drug (amonafide), which was due to the promotion of reactive oxygen species (ROS) level in test cancer cells by the reversible one-electron redox process of ferrocenyl bis-naphthalimide derivatives. Although there was no obvious relationship between the binding constants and the chain length, the structure cytotoxicity relationship revealed that the linker of n = 3, m = 1 was the best choice for the tested tripodol bis-naphthalimide derivatives. SYNOPSIS: A series of tripodal ferrocenyl bis-naphthalimide derivatives were synthesized to study the DNA binding ability and the cytotoxicity induced by reactive oxygen species. All of the compounds exhibited good DNA binding ability. And the structure cytotoxicity relationship revealed that the structure of 5h was the best choice., (Copyright © 2021 Elsevier Inc. All rights reserved.)

We synthesized a series of novel 3-carboranyl-1,8-naphthalimide derivatives, mitonafide and pinafide analogs, using click chemistry, reductive amination and amidation reactions and investigated their in vitro effects on cytotoxicity, cell death, cell cycle, and the production of reactive oxygen species in a HepG2 cancer cell line. The analyses showed that modified naphthalic anhydrides and naphthalimides bearing ortho - or meta -carboranes exhibited diversified activity. Naphthalimides were more cytotoxic than naphthalic anhydrides, with the highest IC 50 value determined for compound 9 (3.10 µM). These compounds were capable of inducing cell cycle arrest at G0/G1 or G2M phase and promoting apoptosis, autophagy or ferroptosis. The most promising conjugate 35 caused strong apoptosis and induced ROS production, which was proven by the increased level of 2'-deoxy-8-oxoguanosine in DNA. The tested conjugates were found to be weak topoisomerase II inhibitors and classical DNA intercalators. Compounds 33 , 34 , and 36 fluorescently stained lysosomes in HepG2 cells. Additionally, we performed a similarity-based assessment of the property profile of the conjugates using the principal component analysis. The creation of an inhibitory profile and descriptor-based plane allowed forming a structure-activity landscape. Finally, a ligand-based comparative molecular field analysis was carried out to specify the (un)favorable structural modifications (pharmacophoric pattern) that are potentially important for the quantitative structure-activity relationship modeling of the carborane-naphthalimide conjugates.

Four series of new 3-nitro naphthalimides derivatives, 4(4a‒4f), 5(5a‒5i), 6(6a‒6e) and 7 (7a‒7j), were designed and synthesized as antitumor agents. Methyl thiazolyl tetrazolium (MTT) screening assay results revealed that some compounds displayed effective in vitro antiproliferative activity on SMMC-7721, T24, SKOV-3, A549 and MGC-803 cancer cell lines in comparison with 5-fluorouracil (5-FU), mitonafide and amonafide. Nude mouse xenotransplantation model assay results indicated that compounds 6b and 7b exhibited good in vivo antiproliferative activity in MGC-803 xenografts in comparison with amonafide and cisplatin, suggesting that compounds 6b and 7b could be good candidates for antitumor agents. Gel electrophoresis assay indicated that DNA and Topo I were the potential targets of compounds 6b and 7b, and comet assay confirmed that compounds 6b and 7b could induce DNA damage, while the further study showed that the 6b- and 7b-induced DNA damage was accompanied by the upregulation of p-ATM, P-Chk2, Cdc25A and p-H2AX. Cell cycle arrest studies demonstrated that compounds 6b and 7b arrested the cell cycle at the S phase, accompanied by the upregulation of the expression levels of the antioncogene p21 and the down-regulation of the expression levels of cyclin E. Apoptosis assays indicated that compounds 6b and 7b caused the apoptosis of tumor cells along with the upregulation of the expression of Bax, caspase-3, caspase-9 and PARP and the downregulation of Bcl-2. These mechanistic studies suggested that compounds 6b and 7b exerted their antitumor activity by targeting to DNA, thereby inducing DNA damage and Topo I inhibition, and consequently causing S stage arrest and the induction of apoptosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Directing energy and charge transfer processes in light-harvesting antenna systems is quintessential for optimizing the efficiency of molecular devices for artificial photosynthesis. In this work, we report a novel synthetic method to construct two regioisomeric antenna molecules (1-D2A2 and 7-D2A2), in which the 4-(n-butylamino)naphthalene monoimide energy and electron donor is attached to the perylene monoimide diester (PMIDE) acceptor at the 1- and 7-bay positions, respectively. The non-symmetric structure of PMIDE renders a polarized distribution of the frontier molecular orbitals along the long axis of this acceptor moiety, which differentiates the electron coupling between the donor, attached at either the 1- or the 7-position, and the acceptor. We demonstrate that directional control of the photo-driven charge transfer process has been obtained by engineering the molecular structure of the light-harvesting antenna molecules.

A series of 3-amino-N-substituted-1,8-naphthalimides and their salicylic Schiff base derivatives were synthesized. The structure of the obtained compounds was confirmed using 1 H and 13 C NMR, FT-IR spectroscopy and elemental analysis and COSY and HMQC for the representative molecules. The photophysical (UV-Vis, PL) and biological properties of all of the prepared compounds were studied. It was found that the amine with the n-hexyl group in EtOH had the highest PL quantum yield (Ф = 85%) compared to the others. Moreover, the chelating properties of the azomethines with the n-hexyl group (1a, 1b, 1c) were tested against various cations (Al 3+ , Ba 2+ , Co 2+ , Cu 2+ , Cr 3+ , Fe 2+ , Fe 3+ , Mn 2+ , Ni 2+ , Pb 2+ , Sr 2+ and Zn 2+ ) in an acetonitrile, acetone and PBS/AC mixture. Compounds that contained the electron withdrawing groups (-Br, -I) had the ability to chelate most of the studied cations, while the unsubstituted derivative chelated only the trivalent cations such as Al 3+ , Cr 3+ and Fe 3+ in acetonitrile. The effect of the environment on the keto-enol tautomeric equilibrium was also demonstrated, especially in the case of the derivative with a bromine atom. The biological studies showed that the tested molecules had no cytotoxicity. Additionally, the ability to image intracellular organelles such as the mitochondria and endoplasmic reticulum was revealed. The crucial role of the hydrolysis of imines for cellular imaging was presented., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

A reaction-based sensor (NAS-1) showed a high affinity and sensitivity to HSO3- via a nucleophilic addition reaction in the aqueous media, giving dual signals from absorption and emission spectra. NAS-1 was successfully applied in RK13 epithelial cells to detect HSO3- in a cellular environment.

Fluorescent sensors are a vital research tool, enabling the study of intricate cellular processes in a sensitive manner. The design and synthesis of responsive and targeted probes is necessary to allow such processes to be interrogated in the cellular environment. This remains a challenge, and requires methods for functionalisation of fluorophores with multiple appendages for sensing and targeting groups. Methods to synthesise more structurally complex derivatives of fluorophores will expand their potential scope. Most known 4-amino-1,8-naphthalimides are only functionalised at imide and 4-positions, and structural modifications at additional positions will increase the breadth of their utility as responsive sensors. In this work, methods for the incorporation of a hypoxia sensing group to 4-amino-1,8-naphthalimide were evaluated. An intermediate was developed that allowed us to incorporate a sensing group, targeting group, and ICT donor to the naphthalimide core in a modular fashion. Synthetic strategies for attaching the hypoxia sensing group and how they affected the fluorescence of the naphthalimide were evaluated by photophysical characterisation and time-dependent density functional theory. An extracellular hypoxia probe was then rationally designed that could selectively image the hypoxic and necrotic region of tumour spheroids. Our results demonstrate the versatility of the naphthalimide scaffold and expand its utility. This approach to probe design will enable the flexible, efficient generation of selective, targeted fluorescent sensors for various biological purposes., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The malondialdehyde (MDA)-specific detection probe (MDA-6) was successfully synthesised through the photoinduced electron transfer (PET) mechanism which possesses many biological applications. In vivo biological applicability of this probe was proved in different cell lines, zebrafish and mice. In these models, the MDA was produced by oxygen stress injury and the relationship between MDA and probe were evaluated in vitro as well as in vivo under different stress conditions. After comparing evaluated results with commercial MDA kit, MDA-6 was concluded with high specificity, low limit of detection (0.03 μM), and can achieve micro-detection of MDA with low cytotoxicity, demonstrating MDA-6 enables safe and effective detection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing for financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

As an important gasotransmitter, hydrogen sulfide having multiple biological roles cannot be easily probed in cells. In this study, a light controllable H 2 S donor, Nap-Sul-ONB, derived from naphthalimide was developed. Under the irradiation of 365 nm light, a readily controlled stimulus, the donor could release COS to form H 2 S and exhibit turn on fluorescence to indicate the release of payload and its cellular location. Besides, the ROS scavenging ability and cell protective effect of Nap-Sul-ONB against endogenous and exogenous ROS were studied. The results showed that upon 365 nm light irradiation, Nap-Sul-ONB could reduce the cellular ROS level and increase the survival rate of PMA-treated cells.

The preparation and characterization of new functional materials for sensing have an important role in clinical diagnosis. Monitoring the surface functionalization of functional material is crucial because the final sensing properties are affected by how the (bio)molecules are immobilized on the surface of solid supports. Here, a new approach for the preparation of functional materials for biomedical diagnosis was developed. This method employs a fluorescent dye comprising 4-amino-1,8-naphthalimide with two orthogonal functional groups suitable for click chemistry. The orthogonal reactivity of these groups allows the sequential functionalization of the fluorophore, firstly with (bio)molecules, and then binding of the (bio)molecule-naphthalimide macrostructure onto the surface of a solid support. The fluorescent properties confirm the immobilization of the (bio)molecule on the surface of the solid support, without requiring other indirect methods to verify the immobilization. These functional materials were tested successfully with sera of patients, thus proving their potential application for allergic drug diagnosis., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Hypochlorite (ClO - ) and hydrogen peroxide (H 2 O 2 ) commonly coexist in organism and are involved in the same physiological and pathological processes. So it is of great importance to develop fluorescent probes to detect both simultaneously. Herein, we reported the first dual-site fluorescent probe (Geisha-1) for the quantitative detection of ClO - and H 2 O 2 . This probe is constructed by chemically grafting N,N-dimethylthiocarbamate and borate to a fluorescence resonance energy transfer (FRET) platform. As a result, Geisha-1 not only presents three different responses to ClO - , H 2 O 2 , and ClO -  + H 2 O 2 (the coexistence of ClO - and H 2 O 2 ) with high sensitivity and selectivity, but also exhibits low toxicity and cell membrane and tissue permeability, and it was further successfully applied to image ClO - and H 2 O 2 in living cells and tissues. Thus, Geisha-1 provides a promising application prospect in biological systems and an alternative strategy for the construction of dual-site fluorescent probes aiming at the multi-response detection of other biologically relevant analytes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Vicinal dithiol-containing proteins (VDPs) play an important role in maintaining the structures and functions of proteins mainly through the conversion between dithiols and disulfide bonds. The content of VDPs also reflects the redox status of an organism. To specifically and expediently detect VDPs, we developed a turn-on monoarsenical fluorescent probe (NEP) based on the intramolecular charge transfer mechanism. Naphthalimide was chosen as a fluorophore and linked with the receptor moiety (cyclic dithiarsolane) via carbamate segment. In the presence of VDPs, NEP displays a strong green fluorescence signal produced by the cyclic dithiarsolane cleavage and subsequent intramolecular cyclization to liberate the fluorophore. Furthermore, NEP exhibits high selectivity toward VDPs over other protein thiols and low molecular weight thiols. The favorable properties of NEP enable it readily to detect VDPs in live cells and in vivo . In addition, a remarkable decrease of VDPs in parkinsonism was disclosed for the first time, highlighting that regulating VDPs level has a therapeutic potential for parkinsonism.

Fluorescent molecularly imprinted polymer (FMIP) optosensor was utilized for the selective identification of 2,4-dichlorophenoxacetic acid (2,4-D) due to worldwide pollution caused by using herbicides in agricultural industry. In this regards, two derivatives of polymerizable 1,8-naphthalimide namely, 1,8-naphthalimide containing thiourea (NI) and diethyl amine tagged 1,8-naphthalimide (NII) were used as the receptors and 2,4-D was applied as a template. Also, precipitation polymerization was applied to prepare the fluorescent molecularly imprinted polymer (FMIP). The morphological, structural and thermal analysis was carried out using SEM, TEM, EDS, BET, FTIR, DSC and TGA for characterizing the fluorescent optosensor. The adsorption efficiency of FMIP and FNIP was studied using Langmuir, Freundlich, BET and Redlich Peterson isotherms. The results represented that the adsorption of 2,4-D on FMIP and FNIP agreed the Freundlich adsorption isotherm with correlation coefficient of 0.9935 and 0.9801, respectively. The prepared sensor was able for the selective determination of 2,4-D salt in the linear range of 5 × 10 -7 -1 × 10 -3  M with a limit of detection of 16.8 nM. The present study revealed that the FMIP prepared by 1,8-naphthalimide derivative (NI) could potentially recognize the trace concentration of 2,4-D. Graphical Abstract Graphical abstract of flourescene switching mechanism in a fluorescent molecularly imprinted polymer sensor.

G-Quadruplex DNAs, formed by G-rich DNA sequences in human genes, are promising targets for design of cancer drugs. In this study, two naphthalimide substituted styryl dyes with different sizes of aromatic groups were synthesized. The spectral analysis showed that the dye X-2 with a large aromatic group formed aggregates in buffer solution displaying very weak fluorescence intensity, and disaggregated in the presence of G-Quadruplex DNAs with large intensity enhancements (up to ~1800 fold). Moreover, X-2 displayed good selectivity to G-Quadruplex DNAs. In contrast, dye X-3 with the smaller aromatic group had much lower fluorescence enhancements and poor selectivity to G-Quadruplex DNAs, suggesting that the suitably sized aromatic ring was essential for the interaction with G-Quadruplex. Further binding studies suggested that X-2 mainly bound on G-quartet surface through end-stacking mode. Cytotoxicity assay showed that both of the two dyes showed good anti-proliferative activities against the cancer cell lines and less cytotoxicity in non-malignant cell lines, which were better than a standard drug 5-fluorouracil. In addition, living cell imaging was also studied and demonstrated the potential applications of the new dye X-2 in bioassays and cell imaging., Competing Interests: Declaration of Competing Interest We declare that we have no conflict of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Two new cytotoxic 1,8-naphthalimide derivatives have been synthesized and characterized. Their biological activities as cytotoxicity and antimicrobial activities and inhibitory activities against DNA-polymerase were evaluated. The interactions of compounds with double-stranded- and quadruple-DNA have been studied by UV-Vis, fluorescent intercalator displacement, competition dialysis, circular dichroism and the findings were compared with the parent naphthalimide and the other compounds. The results show that both compounds (1 and 2) and the parent compound NI have strong cytotoxic activities against Beas-2B, MCF-7, HepG2 and MDA-MB-231 cancer cell lines, antimicrobial activities against Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212 and inhibitory activities towards Taq-polymerase and transcriptase. These novel cationic compounds 1 and 2 can stabilize G-quadruplexes DNA according to thermal denaturation experiments, they change the 3D structure of the DNA (see details in CD experiments) and they exhibit different binding affinities for q-DNA and ds-DNA revealed by spectrophotometric titrations and competitive dialysis studies.

The synthesis and characterization of a series of naphthalimide and phenanthro[9,10-d]imidazole conjugate is described. These compounds are evaluated in vitro for their cytotoxicity towards 60 human cancer cell lines. Derivative 16 shows excellent cytotoxic activity against these cancer cell lines with the range of growth inhibition from -55.78 to 94.53. The most potent derivative (ethylpiperazine, 16) is further studied to evaluate the interaction with ct-DNA using absorption and emission spectroscopy as well as DNA viscosity measurement. The DNA binding studies indicate that compound 16 is significantly interacted with DNA through groove binding having binding constant value of 7.81 × 10 4 M -1 alongwith partial intercalation between the base pairs of DNA strands. Further, topoisomerase inhibition study suggests that compound 16 is induced apoptosis and inhibits human topoisomerase (Topo-IIα) as a possible intracellular target. Molecular docking study of compound 16 with ct-DNA shows good docking score., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

A nuclear-localized fluorescent light-up probe, NucFP-NO 2 , was designed and synthesized that can detect CO selectively in an aqueous buffer (pH 7.4, 37 °C) through the CO-mediated transformation of the nitro group into an amino-functionalized moiety. This probe triggered a more than 55-fold "turn-on" fluorescence response to CO without using any metal ions, e.g., Pd, Rh, Fe, etc. The enhanced response is highly selective over a variety of relevant reactive oxygen, nitrogen, and sulfur species and also various biologically important cationic, anionic, and neutral species. The detection limit of this probe for CO is as low as 0.18 μM with a linear range of 0-70 μM. Also, this fluorogenic probe is an efficient candidate for monitoring intracellular CO in living cells (RAW 264.7, A549 cells), and the fluorescence signals predominantly localize in the nuclear region.

A nitroreductase (NTR) responsive fluorescent probe, Na-NO 2 , comprising p-nitrobenzyl as the unique recognition group and 1,8-naphthalimide as fluorophore, was synthesized. Na-NO 2 showed remarkable fluorescence "turn-on" signal in the presence of NTR under DMSO/H 2 O (1:19, v/v) buffered with PBS (pH = 7) solution in the presence of NADH (300 µM). Furthermore, the probe has a low detection limit down to 3.4 ng/mL and it is very sensitive towards the NTR in Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), normal and tumor cells such as HL-7702, HepG-2 and MCF-7., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

A novel enzyme-responsive supramolecular polysaccharide assembly composed of disulfide linked adamantane-naphthalimide fluorescent camptothecin prodrug (AdaCPT) and β-CD modified hyaluronic acid (HACD) was constructed, possessing low cellular cytotoxicity and exhibiting targeted cellular imaging and controlled drug release at specific sites while providing a concurrent means for the real-time tracking of drug delivery.

The occurrence of and development in the early pathological stage of pancreatic cancer has proved to be associated with microRNAs. However, it remains a great challenge to directly monitor low-expression, and downregulation of, microRNA among living cells, tissues, and serum samples. In this work, Staudinger reduction is first applied in intracellular microRNA detection, establishing a set of smart hybridization-mediated Staudinger reduction probes ( HMSR-probe ) which contain designed oligonucleotide sequences. Meanwhile, 40 serum samples (healthy people (6), patients with pancreatitis (22), and pancreatic cancer patients (12)) are tested for exploring the potential clinical application. Of note, the molecules bound to nucleic acid confine the reactive site to close proximity in a compact space, and nonconnected product from Staudinger reaction facilitates turnover amplification to an ameliorative detection limit (1.3 × 10 -15 M). Moreover, compared with qRT-PCR, a low false positive signal and an excellent specificity makes the probe more suitable and convenient for pancreatic cancer diagnosis in blood samples. For practical applications, HMSR-probe enable accurate differentiation in cell and tissue samples under both 488 and 785 nm and have good coherence to known research. As a proof of concept, the reliable results in distinguishing pancreatic cancer patients from different morbid stages might supply a feasible method for endogenous microRNA detection in fundamental research and clinical diagnostics.

Leishmaniasis is a neglected parasitic disease that is widely seen in more than 60 countries worldwide, including Turkey and its subcontinental region. There are several chemotherapy agents for the treatment of leishmaniasis, including pentavalent antimonials-i.e., sodium stibogluconate (Pentostan) and meglumine antimoniate (Glucantim), pentamidine, conventional amphotericin B deoxycholate, miltefosine, paramomycin (aminosidine), and liposomal amphotericin B. However, these therapies are usually unsatisfactory due to dose-limiting toxicity issues and limited efficacy. Furthermore, resistance gained by parasites endangers future success of these therapies. Addressing these issues, the development of novel drugs with high efficacy has a vital importance. Latest studies have shown that bisnaphthalimidopropyl (BNIP) derivatives display high activity against Leishmaniasis parasites by selectively targeting parasitic sirtuin proteins and interacting with DNA. Despite the promising anti-parasitic activity, the low solubility and toxicity on human macrophages are the limitations to overcome. This study describes the new synthesis strategies for existing-i.e., BNIPDaoct and BNIPDanon-and novel BNIP derivatives differing in respect of their alkyl linker chain lengths. The new synthesis approach provides certain advantages compared to its existing alternatives reported in the literature. The proposed methodology does not only decrease the number of synthesis steps and production time of BNIPDaoct and BNIPDanon, but also provides higher yields, thereby making the synthesis highly cost-effective., Competing Interests: The authors declare no conflicts of interest.

Real-time monitoring of the cytochrome P450 1A1 (CYP1A1) activity in complex biological systems via a practical tool is highly sought after because of its significant role in the metabolism and bioactivation of various xenobiotics. Herein, according to slight differences in the 3D structure and substrate preference between CYP1A1 and its homologous CYP1A2, a series of novel ratiometric fluorescent probes were designed and synthesized using 1,8-naphthalimide because of its trait of naked-eye visualization and ratiometric fluorescence to achieve the detection of CYP1A1 in biological samples. Among these probes, NEiPN showed good water solubility, highly isoform selectivity and great sensitivity (LOD = 0.04874 nM) for CYP1A1 under simulated physiological conditions, which makes it favorable for monitoring CYP1A1 in vivo. Remarkably, NEiPN exhibited excellent reproducibility when it was used to detect the CYP1A1 content in human liver microsomes, which indicated that it has a great potential for quantifying the CYP1A1 content in real biological samples. Furthermore, NEiPN showed relatively low cytotoxicity and has been successfully applied in biological imaging in living cells and zebrafish. These findings indicate that NEiPN is capable of real-time monitoring of the activity of endogenous CYP1A1, which could provide support for CYP1A1-associated pathological processes.

Among the diverse sensing techniques, fluorimetric detection dominates over the other methods because of its rapid signaling, high selectivity and sensitivity, and operational simplicity. This present article delineates fabrication of a fluorescent organic nanoparticle-protamine (FONP-Pro) conjugate for selective and sensitive detection of heparin simply by exploitation of the aggregation-induced emission (AIE) property of the FONPs. Naphthalene diimide-based bola-type amphiphilic molecules (NDI- 1 ) comprise a naphthyl residue and a 3-aminopyridyl unit at both terminals, forming organic nanoparticles in a dimethyl sulfoxide-water binary solvent mixture, and exhibited AIE through excimer formation. The presence of naphthyl residue in the molecular backbone facilitates the intramolecular charge transfer to generate orange-emitting (λ em = 594 nm) AIE-luminogen (AIE-gen). The aminopyridine residues within NDI- 1 induced negative surface charge on NDI- 1 FONPs, which facilitated interaction with positively charged protamine (Pro) to construct FONP-Pro conjugates. Formation of this NDI- 1 FONP-Pro conjugate through the interaction between Pro and FONP drastically reduced the orange emission intensity (fluorescence off) of the AIE-gens. Interestingly, addition of heparin to this FONP-Pro conjugate turned on the fluorescence signal of FONPs through unwinding of the Pro from the FONP surface because of a strong binding affinity between heparin and Pro. Formation of the FONP-Pro conjugate and fluorimetric sensing of heparin was investigated by monitoring the change in emission behavior of NDI- 1 FONPs. Also, the heparin-sensing was found to be highly selective against many other biomolecules including proteins, enzymes, and DNA. Hence, a selective and efficient heparin sensor (FONP-Pro) was developed having a limit of detection of 12 nM simply by utilizing the fluorescence "turn-off" and "turn-on" mechanism of NDI- 1 FONP.

In recent years, targeting drugs made by physical loading or chemical bonding of drugs on small molecular carriers have shown a very wide application prospect in the field of tumor and cancer treatment. How to achieve the release of drugs in cancer cells has become the core of this research. One of the most important bases for drug localization is to use the difference of small molecular biothiol concentration between cancer cells and normal cells. Details of the changes of biothiol levels in the growth and reproduction of cancer cells are still poorly understood, and the main reason is the lack of sensitive real-time imaging tools for biothiols in cancer cells. In this work, we reasonably designed and synthesized the combination of 4-hydroxy-1,8-naphthalimide and NBD-Cl as a concise fluorescent probe HN-NBD for imaging biothiols in live cells and zebrafish. In addition, due to the advantages of HN-NBD design, it is sufficiently sensitive to biothiols, and further imaging can distinguish cancer cells from normal cells. Probe HN-NBD would be of great significance to biomedical researchers for the study of biothiol-related diseases, the screening of new anticancer drugs, and the early diagnosis and treatment of cancers.

A red-emitting and ratiometric fluorescence probe 1 for detecting H 2 O 2 , based on a styrylnaphthalimide-boronate ester was developed. Upon a H 2 O 2 -mediated hydrolysis of boronate ester, probe 1 was transformed to 2 with a ratiometric fluorescence change, decrease at 535 and increase at 640 nm. It was also found that the fluorescent reaction of 1 with H 2 O 2 in solution could be completed within 10 min and the detection limit was estimated to be 0.30 μM. Moreover, this ratiometric change was highly selective for H 2 O 2 over other redox species, metal ions, and anions. Also, this system was found to be capable of detecting H 2 O 2 in the pH range of 6-9. Furthermore, probe 1 was preferentially accumulated into the endoplasmic reticulum (ER) in the live HeLa cells, and an increased H 2 O 2 level in the presence of an ER stress inducer, thapsigargin was revealed., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Fluorogenic substrates are used to visualize the activity of cancer-associated enzymes and to interpret biological events. Certain types of glutathione S-transferase (GST), such as Pi class GST (referred to as GSTP1), are more highly expressed in a wide variety of human cancer tissues compared to their corresponding normal tissues. Pi class GST is thus a cancer cell molecular marker and potential target for overcoming resistance to chemotherapy. Here, we report that 4-bromo-1,8-naphthalimide (BrNaph) is a practical fluorogenic GST substrate. We have found that HE-BrNaph, an N-hydroxyethyl derivative, shows remarkable fluorescence enhancement upon GST-catalyzed S N Ar replacement of the bromo group with a glutathionyl group. This substitution was highly selective and occurred only in the presence of GSH/GSTs; no non-enzymatic reaction was observed. We demonstrated that HE-BrNaph allows visualization of GST activity in living cells and enables to distinguish cancer cells from normal cells. Further, various N-substitutions in BrNaph retain susceptibility to enzymatic activity and isozyme selectivity, suggesting the applicability of BrNaph derivatives. Thus, BrNaph and its derivatives are GST substrates useful for fluorescence imaging and the intracellular detection of GSTP1 activity in living cells., (Copyright © 2019 Elsevier B.V. All rights reserved.)

As a multifunctional signaling molecule, hydrogen sulfide (H 2 S) plays an essential role in diverse physiological and pathological processes. The two-photon fluorescence probes detecting H 2 S selectively in vivo could be useful tools to better study the mechanism of diseases. Then, an efficient two-photon lysosome-specific probe 1 has been developed to detect endogenous H 2 S in living cells and mice. Probe 1 displays excellent properties with 28-fold fluorescence enhancement, marked color changes in naked-eye and fluorescence, high selectivity and sensitivity, and low detection limit (0.22 μM) to H 2 S. These remarkable properties of probe 1 enable its practical applications in detecting H 2 S in environment (wastewater) and food (beer). Moreover, as a two-photon probe under near infrared excitation at 790 nm, probe 1 can monitor the level changes of endogenous H 2 S of lysosome and tumor in living system with good membrane permeability and high imaging resolution. Specially, the probe detecting H 2 S distribution in lysosome could provide more evidences to explain the association of target-organelle and H 2 S., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Elucidating lysosome polarity effect in complicated biosystems was impeded with the deficiency of lacking multi-disease models for researching the relation between lysosomal polarity and diseases. So far, dissecting the abnormal lysosome polarity in the inflamed and obese living mice has not been realized. To overcome this challenge, a robust probe MND-Lys was proposed for monitoring lysosomal polarity with two-photon emission. Using the probe, monitoring the intrinsic polarity variance in embryos and adult zebrafish has been achieved for the first time. Moreover, besides obviously discriminating tumors from normal ones, the probe also enabled tracing polarity changes in inflammatory and obese mice for the first time. The unique tracking and distinguishing polarity in lysosome make the probe a promising agent for fluorescence visualization studies of LD-lysosome related bioprocess and metabolism diseases.

Sulfur dioxide (SO 2 ) plays significant roles in regulating cell apotosis and inflammation. However, there are complex interactions between small biomolecules in cells, and the identification of these coexisting biomarkers remains a challenge. Herein, we report an AND logic gate based fluorescent probe ( NY-Lyso ), operating by responding to pH differences between organelles in cell and selectively reacting with bisulfite (HSO 3 - ). This approach allows the fluorescence of the probe to remain silent under neutral or alkaline conditions, notably, is activated by costimulation of lower pH and bisulfite. Furthermore, it was confirmed to be biocompatible and could be employed to monitor HSO 3 - in lysosomes of living cells. The proposed method demonstrated more practical and outstanding capabilities in targeted and real-time monitoring, providing an effective optical tool for biomarker sensing.

A new 4-amino-1,8-naphthalimide-based fluorescent sensor, with iminoacetic acid and iminoethoxyacetic acid as receptor, was developed. It was applied successfully to detect Zn 2+ in aqueous solution and living cells. Under physiological pH conditions, it demonstrates high selectivity and sensitivity for sensing Zn 2+ with about 7-fold enhancement in aqueous solution, with a characteristic emission band of 4-amino-1,8-naphthalimide with a green color centered at 550 nm., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

An anthracene carboxyimide derivative was synthesized as a colorimetric and fluorogenic sensor to determine NO 2 - with a rapid response (<4 min), excellent selectivity and a low detection limit (84 nM). Paper strips containing the sensor were applied to visually determine the NO 2 - content in food.

Insect chitinolytic β- N-acetylhexosaminidase OfHex1, from the agricultural pest Ostrinia furnacalis (Guenée), is considered as a potential target for green pesticide design. In this study, rational molecular design and optimization led to the synthesis of compounds 15r ( K i = 5.3 μM) and 15y ( K i = 2.7 μM) that had superior activity against OfHex1 than previously reported lead compounds. Both compounds 15r and 15y had high selectivity toward OfHex1 over human β- N-acetylhexosaminidase B (HsHexB) and human O-GlcNAcase (hOGA). In addition, to investigate the basis for the potency of glycosylated naphthalimides against OfHex1, molecular docking and molecular dynamics simulations were performed to study possible binding modes. Furthermore, the in vivo biological activity of target compounds with efficient OfHex1 inhibitory potency was assayed against Myzus persicae, Plutella xylostella, and O. furnacalis. This present work indicates that glycosylated naphthalimides can be further developed as potential pest control and management agents targeting OfHex1.

A series of novel 5-methoxy-2,3-naphthalimide derivatives were designed, synthesized and evaluated for their biological activities. In particular, the ability of the compounds to synergize with antimicrobials, to inhibit Nile Red efflux, and to target AcrB was assayed. The results showed that the most of the tested compounds more sensitized the Escherichia coli BW25113 to the antibiotics than the parent compounds 7c and 15, which were able to inhibit Nile Red efflux. Significantly, compound A5 possessed the most potent antibacterial synergizing activity in combination with levofloxacin by 4 times and 16 times at the concentration of 8 and 16 µg/mL, respectively, whilst A5 could effectively abolish Nile Red efflux at 100 μM. Additionally, target effect of A5 was confirmed in the outer- or inner membrane permeabilization assays. Therefore, A5 is an excellent lead compound for further structural optimization., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Four novel fluorescent cores bearing a transformable functional group based on a π-expanded naphthalimide including a fused pyranone or furan ring have been prepared. Fluorescent probes LysoSers 13-16 for lysosomal targeting have been tested. Co-localization with a commercial lysosome specific marker confirmed that the LysoSers labeled the lysosomal compartment with high selectivity. The LysoSers show excellent brightness and low toxicity.

In this work, taking full advantage of the intramolecular charge transfer (ICT) mechanism, a hydroxynaphthalimide-based ratiometric two-photon fluorescent probe RTP-PN was synthesized to detect ONOO - . Probe RTP-PN could accurately detect ONOO - in the range of 1.4 nM-1.4 μM with the detection limit of 1.4 nM by a ratiometric fluorescence spectroscopy method. Additionally, probe RTP-PN exhibited an ultrafast response for ONOO - than other various species including H 2 O 2 and ClO - . Finally, probe RTP-PN was successfully adopted to detect intracellular ONOO - by the two-photon excitation microscopy., (Copyright © 2018 Elsevier B.V. All rights reserved.)