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[Display omitted] • New fluorescent probe BBP was synthesized for the selective detection of DOXY. • Probe BBP displayed precise fluorometric detection of DOXY with 1:1 binding stoichiometry. • Non-covalent interaction between probe BBP and DOXY was supported by 1H NMR titration and DFT studies. • Probe BBP was successfully employed for rapid detection of DOXY in real samples. Overuse of doxycycline (DOXY) can cause serious problems to human health, environment and food quality. So, it is essential to develop a new sensing methodology that is both sensitive and selective for the quantitative detection of DOXY. In our current research, we synthesized a simple fluorescent probe 4,4′-bis(benzyloxy)-1,1′-biphenyl (BBP) for the highly selective detection of doxycycline by through fluorescence spectroscopy. The probe BBP displayed ultra-sensitivity towards doxycycline due to Forster resonance energy transfer (FRET). Fluorescence spectroscopy, density functional theory (DFT), 1H NMR titration, UV–Vis, and Job's plot were used to confirm the sensing mechanism. The charge transfer between the probe and analyte was further examined qualitatively by electron density differences (EDD) and quantitively by natural bond orbital (NBO) analyses. Whereas the non-covalent nature of probe BBP towards DOXY was verified by theoretical non-covalent interaction (NCI) analysis as along with Bader's quantum theory of atoms in molecules (QTAIM) analysis. Furthermore, probe BBP was also practically employed for the detection of doxycycline in fish samples, pharmaceutical wastewater and blood samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sensor IPA displayed aggregation induced emission properties. • Colorimetric and fluorometric sensing of NB was observed. • Sensor IPA detected NB in solid, solution and vapor phase. • Spectroscopic and DFT studies supported non-covalent interactions. • Detection of nitrobenzene occurs through PET. An electron rich isophthalamide based sensor IPA has been synthesized through a simple two-step reaction, containing noteworthy aggregation induced emission (AIE) properties. Considering the significant emission with λ max at 438 nm, sensor IPA has been employed for the sensing of nitrobenzene (NB) in solid, solution and vapor state with high sensitivity and selectivity. Sensor IPA showed noteworthy colorimetric and fluorometric quenching in fluorescence emission when exposed to NB. Small size of NB and involvement of photoinduced electron transfer (PET) lead to detection of NB down to 60 nM. IPA- NB interaction was studied through UV– Vis. spectroscopic studies along with fluorescence spectroscopy. Moreover, 1H and 13C NMR titration experiments provided additional support for determination of interaction type. Furthermore, by using density functional theory (DFT) calculations, thermodynamic stability was studied. Additionally, non-covalent interactions (NCI), frontier molecular orbitals (FMO), density of states (DOS), were investigated for providing further evidence of nitrobenzene sensing and its interaction with sensor. Natural bond orbital (NBO) analysis was carried out for charge transfer studies. Quantum theory of atom in molecule (QTAIM) and SAPT0 studies provided information about interaction points and binding energy. Additionally, IPA was investigated for NB sensing in real water samples, and its effective participation in solid state on-site detection as well as in solution phase was brought to light along with logic gate construction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fluorescein based probe FHA displayed excellent selectivity against cyanide ion. • Probe FHA gives significant fluorescence enhancement against cyanide ion in real samples. • Cyanide ion detection was based on restriction in isomerization at C = N bond. • NMR, UV Vis. and fluorescence titration experimentations and extensive DFT studies supported non-covalent interactions. A simple and easy to synthesize fluorescein hydrazine derivative (FHA) was designed by direct condensation reaction which exhibited remarkable fluorescence properties. Probe FHA exhibited aggregation induced emission (AIE) property in aqueous media and displayed remarkable sensing ability to selectively detect (CN‾) in real samples. Emission intensity of probe FHA was enormously increased on addition of CN− due to the inhibition of cis–trans isomerization across C = N bond in the probe FHA. The probe FHA selectively detected CN− due to its smaller size that easily penetrated into the spaces of FHA. 1H and 13C NMR titration experimentations were carried out to determine the nature of interaction between CN‾ @ FHA complex. Furthermore, the extensive DFT studies were carried out that includes thermodynamic stability, natural bond orbital (NBO), density of states (DOS), non-covalent interactions (NCIs), frontier molecular orbitals (FMO), and quantum theory of atom in molecule (QTAIM) analysis. All these studies supported the NCIs between CN‾ and FHA. [ABSTRACT FROM AUTHOR]

[Display omitted] • Newly synthesized probe OBP is AIEE active. • Chalcone based probe OBP showed excellent selectivity against drotaverine drug. • Detection of drotaverine drug was carried out in solid and liquid phase. • Probe OBP gives remarkable fluorescent enhancement against drotaverine in real samples. • NMR, UV– Vis. and fluorescence titration experimentations and extensive DFT studies supported non-covalent interactions. A novel chalcone based probe OBP with exquisite aggregation induced emission enhancement (AIEE) has been rationally synthesized through simple two-step process. Owing to remarkable emission characteristics, probe OBP has been employed for selective and sensitive detection of drotaverine (DV) in solution and solid state. Significant fluorometric and colorimetric enhancement in fluorescence emission was displayed by probe OBP at λ max 455 nm after exposure to DV. Photo induced electron transfer (PET) process is responsible for detection of DV through OBP down to nanomolar level. OBP -DV interaction was elucidated through fluorescence and UV– Vis. spectroscopy along with 1H NMR titration experiments. Moreover, density functional theory (DFT) calculations were performed to analyze thermodynamic stability, density of states (DOS), frontier molecular orbitals (FMO), non-covalent interactions (NCI), quantum theory of atom in molecule (QTAIM), electron density difference (EDD) and natural bond orbital (NBO). Additionally, OBP was investigated for DV detection in blood samples as well as in solid state. [ABSTRACT FROM AUTHOR]

[Display omitted] • A deferasirox based fluorescent sensor TAD was developed for selective and sensitive detection of nitrobenzene (NB). • Spectroscopic studies depicted the presence of non-covalent interaction. • Extensive DFT studies supported the non-covalent interaction between sensor TAD and NB. • Practical applicability of sensor ECO was validated by NB detection in real water samples and vapor phase detection. A deferasirox based substituted triazole amine sensor TAD has been synthesized for the highly selective detection of nitrobenzene in real samples. Sensor TAD exhibited selective quenching response against nitrobenzene among the other nitroaromatic compounds (NACs). Photoinduced electron transfer (PET) process was devised as plausible sensing mechanisms which was supported via UV–visible and fluorescence spectroscopy, 1H NMR titration experiment, density functional theory (DFT) analysis and Job's plot. Non-covalent interaction (NCI) analysis and Bader's quantum theory of atoms in molecules (QTAIM) analysis were performed to investigate the presence of non-covalent interactions and symmetry perturbation theory (SAPT0) was performed for energy decomposition and quantitative analysis of interaction energies between sensor TAD and NB. Furthermore, sensor TAD was practically applied for the identification of NB in real samples. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Functionalized analogues of 1,2,4-triazole-2-thiols were synthesized and characterized using spectroscopic techniques. • The synthesized analogues were assessed as thymidine phosphorylase inhibitors and antiangiogenic activity for potential antitumor agents. • Molecular docking study was carried out to understand molecular interaction of 1,2,4-triazoles with thymidine phosphorylase. Abstract Thymidine phosphorylase (TP) is over expressed in several solid tumors and its inhibition can offer unique target suitable for drug discovery in cancer. A series of 1,2,4-triazoles 3a–3l has been synthesized in good yields and subsequently inhibitory potential of synthesized triazoles 3a–3l against thymidine phosphorylase enzyme was evaluated. Out of these twelve analogs five analogues 3b , 3c , 3f , 3l and 3l exhibited a good inhibitory potential against thymidine phosphorylase. Inhibitory potential in term of IC 50 values were found in the range of 61.98 ± 0.43 to 273.43 ± 0.96 μM and 7-Deazaxanthine was taken as a standard inhibitor with IC 50 = 38.68 ± 4.42 μM. Encouraged by these results, more analogues 1,2,4-triazole-3-mercaptocarboxylic acids 4a–4g were synthesized and their inhibitory potential against thymidine phosphorylase was evaluated. In this series, six analogues 4b–4g exhibited a good inhibitory potential in the range of 43.86 ± 1.11–163.43 ± 2.03 μM. Angiogenic response of 1,2,4-triazole acid 4d was estimated using the chick chorionic allantoic membrane (CAM) assay. In the light of these findings, structure activity relationship and molecular docking studies of selected triazoles to determine the key binding interactions was discussed. Docking studies demonstrate that synthesized analogues interacted with active site residues of thymidine phosphorylase enzyme through π-π stacking, thiolate and hydrogen bonding interactions. [ABSTRACT FROM AUTHOR]

Chitin and chitosan are well-thought-out multipurpose biopolymers. Chitosan which is deacetylated chitin is useful than chitin and is biomaterial of great interest. Regardless of its biodegradability, chemical modifications suggest due to the amino side reactivity, helps to impart it other great qualities. Herein, we discuss the preparative methods of synthetically modified derivatives, some are commercially available. This review shields the literature from last few decades. [ABSTRACT FROM AUTHOR]

Reserpine is an indole alkaloid, antipsychotic, and antihypertensive drug that has been used for the control of high blood pressure and for the relief of psychotic symptoms. It was first isolated in 1952 from the dried root of Rauwolfia serpentina whose molecular structure was established in 1953 and natural configuration was published in 1955. The first total synthesis of reserpine was reported by Woodward in 1958. This review article updates current multistep synthetic approaches toward the reserpine natural product and its analogues. [ABSTRACT FROM AUTHOR]

A novel and efficient approach has been established for the synthesis of silver nanoclusters capped silica nanoparticles (SiO 2 @AgNCs). These nanoclusters (AgNCs) capped silica nanoparticles were utilized as a novel ratiometric photoluminescence (PL) nanosensor for extremely sensitive and selective detection of I − and S 2− ions. The AgNCs were prepared in situ on the silica nanoparticles through polyethyleneimine (PEI) template approach. While dual PL emissions of AgNCs (at 500 nm) and luminescent silica nanoparticles (at 602 nm) formed the basis for the ratiometric sensing. The PL emission of AgNCs was strongly quenched by I − (or S 2− ), while that of luminescent silica nanoparticles was hardly affected. The PL emission intensity ratio of AgNCs and the luminescent silica nanoparticles was defined as I 500 /I 602 . A good linear relationship between the I 500 /I 602 value and the concentration of I − (or S 2− ) was observed, and the limit of detection (LOD) was estimated to be 57 nM for I − and 62 nM for S 2− . In addition, the fluorescence images of the SiO 2 @AgNCs nanosensor changed from white to orange upon exposure to different concentrations of I − (or S 2− ) (0–250 μM), which could be clearly distinguished by the naked eye. The SiO 2 @AgNCs nanosensor exhibited good selectivity against other analytes, and I − or S 2− ions could be separately detected via the introduction of proper masking agents. Furthermore, the detection of I − and S 2− in real water samples was also demonstrated. [ABSTRACT FROM AUTHOR]

This review updates the explosive development of gold catalysis for organic transformation focusing on the current literature over last 3 years. Recent investigations have shown that gold catalysis provides catalytically active systems, whereas selectivity and reusability are advantages over noncatalyzed organic transformations. The collected literature is focusing for new organic reactions and synthetic methodologies. Gold can also be suggested for green processes dedicated to fine chemicals, pharmaceuticals, and the food industry due to its recognized biocompatibility. The current review is focused on new methods in the organic synthesis that could be of interest in the wide area of organic chemistry for developing new catalytic pathways. [ABSTRACT FROM AUTHOR]

Thymidine phosphorylase (TP) inhibitors have attracted great attention due to their ability to suppress the tumors formation. In our ongoing research, a series of 1,3,4-oxadiazole-2-thione ( 1 – 12 ) has been synthesized under simple reaction conditions in good to excellent yields (86–98%) and their TP inhibition potential has also been evaluated. The majority of synthesized compounds showed moderate thymidine phosphorylase inhibitory activity with IC50 values ranging from 38.24 ± 1.28 to 258.43 ± 0.43 μM, and 7-deazaxanthine (7DX) was used as a reference compound (IC50 38.68 ± 4.42). The TP activity was very much dependent on the C-5 substituents; among this series the compound 6 bearing 4-hydroxyphenyl group was found to be the most active with IC50 38.24 ± 1.28 μM. Molecular docking studies revealed their binding mode. [ABSTRACT FROM AUTHOR]

Based on the fact that the thymidine phosphorylase inhibitors are considered potential anti-tumor agents, a range of novel oxadiazole derivatives 3a–3u was designed and synthesized by a simple and facile synthetic route. The biological assay revealed that majority of compounds displayed modest inhibitory activity against thymidine phosphorylase at low micromolar concentrations (IC50 173.23±3.04 to 14.40±2.45μM). In the current study the most active compounds were 3h and 3q with IC50 values 14.40±2.45 and 17.60±1.07μM, respectively. Molecular docking studies were performed on the most active compounds (3h, 3k, 3o–3q) to show their binding mode. [ABSTRACT FROM AUTHOR]

• Analogues of ciprofloxacin were synthesized under convenient reaction conditions. • The synthesized ciprofloxacin analogues were found inhibitors of thymidine phosphorylase. • Selective analogue was evaluated for antiangiogenic activity for the development of future anticancer drugs. • Molecular docking study revealed detailed molecular interaction of synthesized analogues with thymidine phosphorylase. Over expression of thymidine phosphorylase (TP) in various human tumors compared to normal healthy tissue is associated with progression of cancer and proliferation. The 2-deoxy- d -ribose is the final product of thymidine phosphorylase (TP) catalyzed reaction. Both TP and 2-deoxy- d -ribose are known to promote unwanted angiogenesis in cancerous cells. Discovery of potent inhibitors of thymidine phosphorylase (TP) can offer appropriate approach in cancer treatment. A series of ciprofloxacin 2 , 3a–3c , 4a–4d , 5a–5b , 6 and 7 has been synthesized and characterized using spectroscopic techniques. Afterwards, inhibitory potential of synthesized ciprofloxacin 2 , 3a–3c , 4a–4d , 5a–5b , 6 and 7 against thymidine phosphorylase enzyme was assessed. Out of these twelve analogs of ciprofloxacin nine analogues 3a–3c , 4a–4c , 5a–5b and 6 showed good inhibitory activity against thymidine phosphorylase. Inhibitory activity as presented by their IC 50 values was found in the range of 39.71 ± 1.13 to 161.89 ± 0.95 μM. The 7-deazaxanthine was used as a standard inhibitor with IC 50 = 37.82 ± 0.93 μM. Furthermore, the chick chorionic allantoic membrane (CAM) assay was used to investigate anti-angiogenic activity of the most active ciprofloxacin-based inhibitor 3b. To enlighten the important binding interactions of ciprofloxacin derivatives with target enzyme, the structure activity relationship and molecular docking studies of chosen ciprofloxacin analogues was discussed. Docking studies revealed key π-π stacking, π-cation and hydrogen bonding interactions of ciprofloxacin analogues with active site residues of thymidine phosphorylase enzyme. [ABSTRACT FROM AUTHOR]

A group of new thermodynamically more stable E -2-styrylbenzohydrazide derivatives (5a-i) were synthesized via palladium catalyzed Mizoroki-Heck reaction conditions. All synthesized compounds were characterized by UV-visible, FT-IR, 1H NMR, 13C NMR, mass spectrometry and elemental analysis. Anticancer potential of all synthesized E -stilbene analogues (5a-i) were investigated via cell proliferation assay and apoptosis by Hoechst 33258 staining assay. The most active compound (5e) showed significant anticancer potential against estrogen dependent human breast cancer cells (MCF-7). The cell viability and apoptosis of compound (5e) was found 56 ± 0.06% and 80.09 ± 0.07% respectively as compared to standard drug (Doxorubicin) with cell viability of 62 ± 0.03% and apoptosis 73.69 ± 0.05%. Docking studies revealed higher efficacy of compound (5e) owing to its better binding affinity and ligand efficiency scores (Ki = 0.000076 nMol). All stilbene hydrazides (5a-i) exhibited significant anticancer activity against human breast cancer cells (MCF-7). Therefore, stilbene analogues with hydrazide moiety may offer immense potential for future therapeutic and pharmaceutical applications. A new series of E -2-styrylbenzohydrazide derivatives (5a-i) have been synthesized, characterized by 1H NMR, and 13C NMR and screened for their in vitro anticancer activity against human breast cancer cells (MCF-7). All of the synthesized compounds showed good to excellent anticancer activity. Kinetic and docking study of the most potent compound 5e was also performed. Image 1 • Various stilbene hydrazides were synthesized by palladium-catalyzed Mizoroki-Heck reaction. • All stilbene hydrazides were evaluated for their anticancer activity through cell proliferation assay. • Stilbene hydrazides presented extraordinary potential as anticancer agents. • Computational studies were performed to understand their interactions. • They demonstrated promising potential binding energies and ligand efficiency scores. [ABSTRACT FROM AUTHOR]

A series of new extensively conjugated E-stilbene azomethines (5a-5h) were synthesized and screened for their antioxidant and antimicrobial activity. The compounds were tested against bacterial (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Bacillus subtilis) and fungal strains (Aspergillus niger, A. flavus, and Trichoderma harzianum) using the agar well diffusion method. Among the tested compounds, N '-(4-nitrobenzylidene)- 2-((E) -styryl)benzohydrazide (5g) was found to possess potent antimicrobial activity higher than some drugs with significant activity reported in the literature, e.g., cefradine and terbinafine hydrochloride. Additionally, compounds 5a-5h were also evaluated for antioxidant potential using DPPH free radical scavenging and ferric thiocyanate (FTC) assays. Among these, N '-(4-hydroxybenzylidene)-2-((E) -styryl)benzohydrazide (5e) exhibited significant antioxidant potential by both assays. Compound 5e demonstrated higher DPPH free radical scavenging activity (IC50 = 22 ± 0.19 μ g/mL) than the standard, butylated hydroxytoluene (BHT; IC50 = 28 ± 0.10 μ g/mL). A similar trend was observed for compound 5e in FTC assay, which exhibited 86 ± 0.19% inhibition, whereas the BHT control showed 81 ± 0.21% inhibition of linoleic acid peroxidase. The structure elucidation of the synthesized compounds was carried out by UV-Vis, FT-IR, 1 H NMR, 13 C NMR, and elemental analysis and mass spectrometry. These results suggest possible use of these compounds for the rational design of new antimicrobial and antioxidant agents. [ABSTRACT FROM AUTHOR]

The major cause of hyperglycemia can generally be attributed to β-glucosidase as per its involvement in non-alcoholic fatty liver disease. This clinical condition leads to liver carcinoma (HepG2 cancer). The phthalimides and phthalamic acid classes possess inhibitory potential against glucosidase, forming the basis for designing new phthalimide and phthalamic acid analogs to test their ability as potent inhibitors of β-glucosidase. The study also covers in silico (molecular docking and MD simulations) and in vitro (β-glucosidase and HepG2 cancer cell line assays) analyses. The phthalimide and phthalamic acid derivatives were synthesized, followed by spectroscopic characterization. The mechanistic complexities associated with β-glucosidase inhibition were identified via the docking of the synthesized compounds inside the active site of the protein, and the results were analyzed in terms of the best binding energy and appropriate docking pose. The top-ranked compounds were subjected to extensive MD simulation studies to understand the mode of interaction of the synthesized compounds and binding energies, as well as the contribution of individual residues towards binding affinities. Lower RMSD/RMSF values were observed for 2c and 3c, respectively, in the active site, confirming more stabilized, ligand-bound complexes when compared to the free state. An anisotropic network model was used to unravel the role of loop fluctuation in the context of ligand binding and the dynamics that are distinct to the bound and free states, supported by a 3D surface plot. An in vitro study revealed that 1c (IC50 = 1.26 µM) is far better than standard acarbose (2.15 µM), confirming the potential of this compound against the target protein. Given the appreciable potential of the candidate compounds against β-glucosidase, the synthesized compounds were further tested for their cytotoxic activity against hepatic carcinoma on HepG2 cancer cell lines. The cytotoxicity profile of the synthesized compounds was performed against HepG2 cancer cell lines. The resultant IC50 value (0.048 µM) for 3c is better than the standard (thalidomide: IC50 0.053 µM). The results promise the hypothesis that the synthesized compounds might become potential drug candidates, given the fact that the β-glucosidase inhibition of 1c is 40% better than the standard, whereas compound 3c holds more anti-tumor activity (greater than 9%) against the HepG2 cell line than the known drug. [ABSTRACT FROM AUTHOR]

The binding behavior of graphene oxide and metal nanoparticles (Au, Pt, and Pd) was observed by UV–Vis spectroscopy, fluorescence spectroscopy, dynamic light scattering, and zeta potential. Hybrids with a fixed concentration of graphene oxide (GO) were prepared with increasing concentration of metal nanoparticles to observe the effect of binding on their spectroscopic properties, size, and zeta potential. An increase in the absorption spectra of GO after binding with nanoparticles and a gradual decrease in fluorescence emission intensity with increasing concentration of nanoparticles was observed, representing their effective binding. Stern–Volmer plots differentiated the quenching constants of these nanoparticles, where Au shows the lowest and Pd shows the highest quenching among these nanoparticles. The initial hybrids showed more size change as compared to hybrids with a higher concentration of nanoparticles, whereas initial hybrids have charge similar to that of GO and gradual increase in the concentration of nanoparticles bring the charge near to the respective charge of nanoparticles. To the best of our understanding, this is the first report of its kind to study the binding interactions of two different moieties by studying changes occurred in the hydrodynamic radius and zeta potential of hybrids by titration experiments, having applications in surface treatment, drug delivery, and as sensors for environmental pollutants or other classes of organic molecules, etc. [ABSTRACT FROM AUTHOR]

This review paper covers recent advances in the synthetic strategies for novel TPase inhibitors and their potential medicinal applications over the last few decades. A brief introduction covering the structural aspects of TPase inhibitors is also included to facilitate understanding of diverse approaches to monitor the design of new inhibitors. TPase is an essential enzyme and its inhibition is a potential target in the development of anticancer drugs. [ABSTRACT FROM AUTHOR]

Wound healing is a complicated process that can be susceptible toward infection caused by bacteria. The surging drug resistance has become one of the biggest challenges to the treatment of these infections in public health. Herein, a new asymmetrical aza-boron-dipyrromethene (ABDP) probe is prepared and encapsulated with cholesterol-modified polyethylene glycol polymer (Chol-PEG 2000-NH 2) to construct a PTT/PDT dual-modality antibacterial agent (the ABDP NPs) and provide a new material for the treatment of MRSA-based infections. The ABDP NPs show remarkable wide UV–Vis absorption at 300–850 nm and superior bactericidal effects against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Methicillin-resistant S. aureus (MRSA), which can be controlled by a phototheranostic antibacterial switch (808 nm laser). Histological analysis indicates that wounds treated by the ABDP NPs plus NIR laser irradiation exhibit more complete re-epithelialization, abundant collagen fibers, and higher hair follicle numbers than the vancomycin-treated group. This study provides a promising perspective using aza-BODIPY dye for the treatment of multidrug-resistant bacteria-based infections and clinical applications in the future. [ABSTRACT FROM AUTHOR]

A fluorescence turn-on assay was established for ALP (alkaline phosphatase) based on Cu2+ catalyzed Fenton-like reaction and Graphene Oxide (GO). GO was utilized to quench the fluorescence of fluorescein (FAM) labeled single strand DNA (F-DNA). ALP can remove the phosphate group in sodium ascorbyl phosphate (SAP), and convert it into reducing ascorbate. Highly reactive hydroxyl radicals (·OH) were generated in the presence of ascorbate and Cu2+ through the Fenton-like reaction. The reactive radicals generated in situ caused the cleavage of F-DNA into small fragments. When GO was added, the fluorescence emission of the sample without ALP was quenched and fluorescence emission recovered in the presence of ALP. The intensity of the recovered fluorescence was directly related to the concentration of ALP in the assay solution, and a sensitive and selective facile ALP assay is therefore established. Graphical abstractHighlights· An alkaline phosphatase assay was developed with high sensitivity and selectivity. · Graphene oxide was used for the efficient quenching of fluorescence dye labeled single stranded DNA. · The Cu2+ catalyzed Fenton-like reaction was utilized for the breakdown of dye labeled single stranded DNA. · The assay could also be used for the facile screening of ALP inhibitors. [ABSTRACT FROM AUTHOR]

[Display omitted] • Probe NAB was successfully developed for sensing of esomeprazole at dual wavelength and chloroform traces. • Probe showed solvatochromism and aggregation induced emission enhancement (AIEE) properties with j-aggregates formation. • LC-MS, NMR, UV– Vis. spectroscopy and DFT confirmed the presence of non-covalent interactions with analyte. • Probe was used for solid state detection of esomeprazole (EMZ) and in real samples (blood and urine). A benzothiazole based probe (NAB) synthesized through single step imidation reaction showed AIEE properties with remarkable red shift from 385 nm to 470 nm indicating formation of J aggregates. Probe NAB efficiently detected esomeprazole (EMZ) at dual wavelengths (385 and 470 nm) through quenching of fluorescence emission with LOD values of 41 nM and 51 nM, respectively. Using fluorescence, UV– Vis. and NMR spectroscopy, along with LC-MS experiments, SEM and DFT studies, involvement of photoinduced electron transfer (PET) and non-covalent interactions in sensing of EMZ was confirmed. The probe NAB was also used for the detection of chloroform in DCM as well as emissive behavior in different solvents was recorded for solvatochromism studies. The unique solid state fluorescence emission of probe NAB provided convenient way for the detection of EMZ. TLC and filter papers based test strips were fabricated for convenient detection of EMZ under 365 nm UV lamp. Newly developed fluorescent probe demonstrated successful detection of esomeprazole in blood and urine samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesized sensor BMP is AIEE active. • Chalcone based dual sensor has been synthesized for Zn2+, 4-NP and chloroform detection. • Zn2+ and 4-NP were sensed by BMP through CHEF and PET phenomenon. • BMP sensor can be employed as invisible ink. • NMR, UV– Vis. and fluorescence titration experimentations and extensive DFT studies supported non-covalent interactions. Excessive utilization of Zn2+ and 4-nitrophenol (4-NP) in multiple fields has been becoming a serious threat to the environment and human health from a long time. Considering this, a multipurpose, extremely sensitive and selective fluorescent sensor BMP has been developed for the sensing of Zn2+, 4-NP and chloroform. Chalcone based sensor BMP was easily synthesized through simple aldol condensation reaction that possessed remarkable aggregation induced emission enhancement (AIEE) features along with the formation of J-aggregates. The particle size of aggregates was measured by DLS analysis. Sensor BMP showed strong emission at wavelength 430 nm. Moreover, sensor BMP showed different emissive behavior in various solvents. Sensor BMP selectively detected the Zn2+ through Chelation Enhanced Fluorescence (CHEF) intensity. BMP sensor has selectively sensed the 4-NP through photo-induced electron transfer (PET) quenching mechanism. Along with Zn2+ and 4-NP the sensor BMP has interestingly detected the percentage of chloroform in DCM. The calculated values of limit of detection for Zn2+, 4-NP and chloroform is 43 nM, 18 nM and 0.1 % v/v, respectively. UV–Visible, 1H NMR, LC-MS titration, and SEM experiments were also executed to verify the interaction of BMP sensor with respective analytes. Furthermore, the experimental findings were further justified through the theoretical studies including energy calculation of orbitals and nature of interactions. BMP sensor was employed in both solution and solid state for successful sensing of Zn2+, 4-NP and chloroform in real samples. [ABSTRACT FROM AUTHOR]

Small molecules with nitrogen-containing scaffolds have gained much attention due to their biological importance in the development of new anticancer agents. The present paper reports the synthesis of a library of new dihydropyridine and pyridine analogs with diverse pharmacophores. All compounds were tested against the human tissue nonspecific alkaline phosphatase (h-TNAP) enzyme. Most of the compounds showed excellent enzyme inhibition against h-TNAP, having IC50 values ranging from 0.49 ± 0.025 to 8.8 ± 0.53 µM, which is multi-fold higher than that of the standard inhibitor (levamisole = 22.65 ± 1.60 µM) of the h-TNAP enzyme. Furthermore, an MTT assay was carried out to evaluate cytotoxicity against the HeLa and MCF-7 cancer cell lines. Among the analogs, the most potent dihydropyridine-based compound 4d was selected to investigate pro-apoptotic behavior. The further analysis demonstrated that compound 4d played a significant role in inducing apoptosis through multiple mechanisms, including overproduction of reactive oxygen species, mitochondrial dysfunction, DNA damaging, and arrest of the cell cycle at the G1 phase by inhibiting CDK4/6. The apoptosis-inducing effect of compound 4d was studied through staining agents, microscopic, and flow cytometry techniques. Detailed structure–activity relationship (SAR) and molecular docking studies were carried out to identify the core structural features responsible for inhibiting the enzymatic activity of the h-TNAP enzyme. Moreover, fluorescence emission studies corroborated the binding interaction of compound 4d with DNA through a fluorescence titration experiment. [ABSTRACT FROM AUTHOR]

Apart from environmental implications, the extreme toxicity of cyanide can lead to sudden human death upon prolonged exposure to it. Hence, rapid and low-level on-site detection of cyanide has earned paramount significance in the present era. Therefore, an AIEE active and piezofluorochromic Schiff base (probe 2) was synthesized which exhibited highly selective fluorescence enhancement based nanoscale (LOD; 6.17 nM) detection of CN−. The interaction mode was attributed to the deprotonation of the probe by the cyanide that was confirmed through 1H NMR titration, pH, theoretical studies, and switchable fluorescence response upon the addition of HCl. Advantageously, probe 2 displayed solid and vapor phase recognition of cyanide which is the first of its kind as far as we know. The excellent sensing potential of the probe was satisfactorily applied for the detection of cyanide in food, natural soil, and industrial wastewater. Additionally, probe 2 showed an immediate colorimetric response towards cyanide which was favorably integrated through a smartphone. Finally, the switchable fluorescence response of the probe was used to design an INHIBIT logic gate. Therefore, the multifunctional probe 2 displayed excellent practical potential for cyanide detection which was the ultimate goal of our work. [ABSTRACT FROM AUTHOR]

(1) Background: Achillea mellifolium belongs to a highly reputed family of medicinal plants, with plant extract being used as medicine in indigenous system. However, limited data is available regarding the exploitation of the medicinal potential of isolated pure compounds from this family; (2) Methods: A whole plant extract was partitioned into fractions and on the basis of biological activity, an ethyl acetate fraction was selected for isolation of pure compounds. Isolated compounds were characterized using different spectroscopic techniques. The compounds isolated from this study were tested for their medicinal potential using in-vitro enzyme assay, coupled with in-silico studies; (3) Results: Three new acrylic acid derivatives (1–3) have been isolated from the ethyl acetate fraction of Achillea mellifolium. The characterization of these compounds (1–3) was carried out using UV/Vis, FT-IR, 1D and 2D-NMR spectroscopy (1H-NMR, 13C-NMR, HMBC, NOESY) and mass spectrometry. These acrylic acid derivatives were further evaluated for their enzyme inhibition potential against urease from jack bean and α glucosidase from Saccharomyces cerevisiae, using both in-silico and in-vitro approaches. In-vitro studies showed that compound 3 has the highest inhibition against urease enzyme (IC50 =10.46 ± 0.03 μΜ), followed by compound 1 and compound 2 with percent inhibition and IC50 value of 16.87 ± 0.02 c and 13.71 ± 0.07 μΜ, respectively, compared to the standard (thiourea-IC50 = 21.5 ± 0.01 μΜ). The investigated IC50 value of compound 3 against the urease enzyme is two times lower compared to thiourea, suggesting that this compound is twice as active compared to the standard drug. On the other hand, all three compounds (1–3) revealed mild inhibition potential against α-glucosidase. In-silico molecular docking studies, in combination with MD simulations and free energy, calculations were also performed to rationalize their time evolved mode of interaction inside the active pocket. Binding energies were computed using a MMPBSA approach, and the role of individual residues to overall binding of the inhibitors inside the active pockets were also computed; (4) Conclusions: Together, these studies confirm the inhibitory potential of isolated acrylic acid derivatives against both urease and α-glucosidase enzymes; however, their inhibition potential is better for urease enzyme even when compared to the standard. [ABSTRACT FROM AUTHOR]

• A deferasirox based sensor DPA was successfully synthesized by single step imidation reaction. • Sensor DPA exhibited AIEE property along with remarkable bathochromic shift. • Sensor DPA was employed for selective and sensitive fluorescence based sensing of NB. • The spectroscopic and DFT simulations verified the existence of non-covalent interaction between nitrobenzene and sensor. A deferasirox based sensor DPA was rationally designed through single step amidation reaction. Sensor DPA exhibited aggregation induced emission enhancement (AIEE) property that was attributed to restriction in intramolecular rotation (RIR). Moreover, the sensor DPA displayed remarkable bathochromic shift (red-shift) of 110 nm in wavelength, ascribed to formation of J -aggregates. Furthermore, sensor DPA was employed for the selective and sensitive fluorescence based sensing of hazardous and carcinogenic nitrobenzene (NB). The sensor DPA successfully detected NB in solution through the quenching of emission intensity. The quenching of sensor fluorescence intensity was ascribed to photoinduced electron transfer (PET) mechanism. The sensing mechanism was investigated by 1H NMR titration experiment, Job's plot and density functional theory (DFT) calculations. Additionally, the existence of non-covalent interactions between sensor DPA and NB were examined by Bader's Quantum theory of atoms in molecules (QTAIM) and non-covalent interaction (NCI) analysis. Finally, sensor DPA was employed for the detection of volatile nitrobenzene in vapor phase. [Display omitted] [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs)-based therapy opens a new area for antibiotic-drug free infections treatment. In the present study, chitosan membranes (CS) loaded with two concentrations of copper-MOF 10 mg/20 ml (Cu-MOF10/CS) & 20 mg/20 ml (Cu-MOF20/CS) were prepared by a simple lyophilization procedure. FTIR spectra of Cu-MOF10/CS and Cu-MOF20/CS dressings confirmed absence of any undesirable chemical changes after loading Cu-MOF. The SEM images of the synthesized materials (CS, Cu-MOF10/CS & Cu-MOF20/CS) showed interconnected porous structures. Cytocompatibility of the materials was confirmed by fibroblasts cells culturing and the materials were hemocompatible, with blood clotting index <5 %. Cu-MOF20/CS showed comparatively higher effective antibacterial activity against the tested strains; E. coli (149.2 %), P. aeruginosa (165 %) S. aureus (117.8 %) and MRSA (142 %) as compared to Amikacin, CS and Cu-MOF10/CS membranes. Similarly, Cu-MOF20/CS dressing significantly eradicated the biofilms; P. aeruginosa (37 %) and MRSA (52 %) respectively. In full thickness infected wound rat model, on day 23, Cu-MOF10/CS and Cu-MOF20/CS promoted wound healing up to 87.7 % and 82 % respectively. H&E staining of wounded tissues treated with Cu-MOF10/CS & Cu-MOF20/CS demonstrated enhanced neovascularization and re-epithelization along-with reduced inflammation, while trichrome staining exhibited increased collagen deposition. Overall, this study declares Cu-MOFs loaded chitosan dressings a multifunctional platform for the healing of infected wounds. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Probe PPN ratiometrically detected mefenamic acid. • Spectroscopic studies proved noncovalent interactions. • Extensive DFT studies were conducted to analyze interactions. • Probe PPN was employed in real samples to detect traces of mefenamic acid. Over intake of mefenamic acid (MA) cause morbidity, mortality, liver damage, and hepatic necrosis. For this reason, it is of great importance to discover novel methodologies that provide sharp detection timing, improved sensing efficiency, and profound reproducibility in MA detection. In our current research, we synthesized a naphthalic anhydride based probe PPN which revealed excellent sensing potential towards MA. Probe PPN exhibited ratiometric fluorescence against MA based on complex formation and photoinduced electron transfer (PET) process. Detection mechanism was verified through Density functional theory (DFT) calculations and 1H NMR titration experiments. The type of interaction between probe PPN and MA was investigated through quantum theory of atoms in molecules (QTAIM) analysis and noncovalent interaction (NCI) analysis and was further evaluated via spectroscopic analysis. Moreover, the probe PPN was practically employed to the sensing of MA in artificial urine, pharmaceutical wastewater, and blood samples. Probe PPN is the most streamlined probe designed ever for the sensing of MFA in complex environments with extreme selectivity and sensitivity. [ABSTRACT FROM AUTHOR]

• Twenty analogues of thiobarbiturate and bis-thiobarbiturate were synthesized in good yields and found good urease inhibitors. • Out of these twenty analogues, ten analogues 5a–5k exhibited potent inhibitory activity. • Compounds 5j and 5k having o-fluoro (IC50 8.42 ± 0.32 µM) and p-fluoro (IC50 9.81 ± 0.32 µM) were found the most potent urease inhibitors. • Docking studies revealed the best binding scores for 5e (–12.20 kcal/mol), 5f (–17.49 kcal/mol), 5 h (–17.86 kcal/mol), 5i (–16.83 kcal/mol) and 5j (–15.87 kcal/mol). A series of thiobarbiturates 4a–4e and bis -thiobarbiturates analogues 5a–5o has been synthesized by condensing 1,3-diethylthiobarbituric acid 3 with a variety of aromatic aldehydes with varied structural features and substitution at active methylene position of thiobarbituric acid. Afterward, chemical structures of newly synthesized analogues of thiobarbituric acid were characterized through FT-IR, NMR spectroscopy and mass spectrometry. Subsequently, the inhibitory potential of thiobarbiturates 4a–4e and bis -thiobarbiturates analogues 5a–5o against urease enzyme was evaluated. The inhibitory potential of all synthesized analogues in terms of IC 50 value was observed in the range of 8.42 ± 0.32 to 79.34 ± 0.52 μM by comparing with thiourea (IC 50 21.25 ± 0.15 μM) as a standard urease inhibitor. Out of these twenty analogues, most of the analogues exhibited potent inhibitory activity against urease. After interesting findings, structure activity relationship (SAR) has been established for all analogues. Docking studies revealed that synthesized analogues interacted with active site residues of bimetallic nickel center of the urease enzyme through, thiolate, π-π stacking and hydrogen bonding interactions. Image, graphical abstract [ABSTRACT FROM AUTHOR]

This review covers the recent applications of iodocarbocyclization reactions in synthetic organic chemistry over the last few decades. A variety of carbocycles and heterocycles could be synthesized by iodocarbocyclization reactions. The important applications of iodocarbocyclization reaction in synthetic organic chemistry cover up different features that have been consolidated in this review. [ABSTRACT FROM AUTHOR]

A group of new nitro substituted benzoxazinones (3a-k) were synthesized from easily available 4-nitroanthranilic acid. All the synthesized compounds were characterized by FT-IR, 1H NMR, 13C NMR, mass spectrometry and elemental analysis. Anti-proliferative and pro-apoptotic potential of all the synthesized compounds (3a-k) was evaluated by MTT and Hoechst 33258 staining assay respectively whereas their antioxidant properties were determined via DPPH free radical scavenging assay. The most active compounds (3a , 3c and 3k) showed significant cytotoxic potential against HeLa cells with an inhibition of cell viability that ranged between 28.54 and 44.67% (P < 0.001). Albeit statistically different, the anti-proliferative effect of 3c was in close match with that of the reference drug doxorubicin. Likewise, the test compounds showed profound pro-apoptotic potential with an apoptotic index that ranged between 52.86 and 75.61%. Besides, the docking studies revealed a higher efficiency for compounds (3a and 3h) owing to their better affinity and inhibition constant (K i = 4.397 and 3.713 nmol) respectively. The antioxidant potential of synthesized benzoxazinones (3a-k) was in close agreement with the experimental anticancer results with a percent inhibition from 34.45 to 85.93% as compared to standard (90.56%). A new series of benzoxazinones (3a-k) have been synthesized, characterized by FT-IR, 1H NMR, and 13C NMR and screened for their in vitro anticancer activity against HeLa cancer cell line. All synthesized compounds demonstrated good anticancer activity. Kinetic and docking study of potent compound 3a were also performed. Image 1 • Various benzoxazine-4-ones were synthesized by simple methodology. • Synthesized benzoxazinones were evaluated for their anticancer potential against HeLa cancer cells through cell proliferation assay. • Benzoxazinones presented good anticancer potential. • Computational studies were performed to understand their interactions. [ABSTRACT FROM AUTHOR]

The current review covers explosive development of various synthetic approaches for piperidine scaffold and its analogues in the last few decades. The piperidine ring system is a key motif in many natural alkaloids and synthetic organic compounds. Further, piperidine moiety has gained significant consideration in drug discovery due to its wide range of therapeutic applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A stilbene based fluorescent sensor ECO was developed for selective and sensitive detection of MFA. • The stilbene sensor ECO can detect MFA with 1:1 binding stoichiometry. • Spectroscopic and DFT studies supported the presence of non-covalent interaction between sensor ECO and MFA. • Practical applicability of sensor ECO was validated for MFA detection in blood and urine samples. Abnormal levels of mefenamic acid (MFA) in living organisms can result in hepatic necrosis, liver, and gastrointestinal diseases. Therefore, development of accurate and effective method for detection of MFA is of great significance for the protection of public health. Herein, we designed a stilbene based sensor ECO for the sensitive and selective detection of mefenamic acid by employing fluorescence spectroscopy for the first time. The developed sensor ECO displayed fluorescence turn-off response towards MFA based on PET (photoinduced electron transfer) and hydrogen bonding. The sensing mechanism of MFA was investigated through 1H NMR titration experiment and density functional theory (DFT) calculations. The presence of non-covalent interaction was confirmed through spectroscopic analysis and was further supported by non-covalent interaction (NCI) analysis and Bader's quantum theory of atoms in molecules (QTAIM) analysis. Additionally, the sensor ECO coated test strips were fabricated for on-site detection of mefenamic acid. Furthermore, the practical applicability of sensor ECO to detect MFA was also explored in human blood and artificial urine samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Triazine based sensor displayed excellent selectivity for sequential detection of Hg2+ and L-Cysteine. • Sensor was deployed for the detection of Hg2+ and Cys in real samples (industrial water, whitening creams and milk). • Detection of Hg2+ was based on chelation enhanced fluorescence (CHEF) and inhibition of ICT. • Extensive DFT calculations supported the plausible sensing mechanisms and nature of interactions. Triazine based fluorescent sensor TBT was rationally designed and synthesized to achieve sequential detection of Hg2+ and L-cysteine based on the presence of sulfur moiety and suitable cavity in the molecule. Sensor TBT exhibited excellent sensing potential for the selective detection of Hg2+ ions and L-cysteine (Cys) in real samples. Upon addition of Hg2+ to sensor TBT , enhancement in emission intensity of sensor TBT was observed which was accredited to the presence of sulfur moiety and size of cavity in the sensor. Upon interaction with Hg2+ blockage of intramolecular charge transfer (ICT) along with chelation-enhanced fluorescence (CHEF) resulted in the increase in fluorescence emission intensity of sensor TBT. Further, TBT -Hg2+ complex was employed for the selective detection of Cys through fluorescence quenching mechanism. This was attributed to the significantly stronger interaction of Cys with Hg2+, which resulted in the formation of Cys-Hg2+ complex and subsequently sensor TBT was released from TBT -Hg2+ complex. The nature of interaction between TBT -Hg2+ and Cys-Hg2+ complex was evaluated through 1H NMR titration experimentations. Extensive DFT studies were also carried out which include thermodynamic stability, frontier molecular orbitals (FMO), density of states (DOS), non-covalent interaction (NCI), quantum theory of atom in molecule (QTAIM), electron density differences (EDD) and natural bond orbital (NBO) analyses. All the studies supported the non-covalent type of interaction between analytes and sensor TBT. The limit of detection for Hg2+ ions was found to be as low as 61.9 nM. Sensor TBT was also employed for the quantitative detection of Hg2+ and Cys in real samples. Additionally, logic gate was fabricated by using sequential detection strategy. [ABSTRACT FROM AUTHOR]

Abstract Proteases, as one of the most significant kind of digestive enzymes, are closely related to a variety of physiological processes and diseases. Herein, a black phosphorus nanosheets (BPs) based sensitive fluorometric method for protease detection and inhibitor screening is proposed. The aqueous solution of perylene probe (probe 1) displays a strong fluorescence. BPs, as novel discovered two-dimensional (2D) materials, can adsorb probe 1 through electrostatic interactions, which causes fluorescence quenching of probe 1. Histone can control the interactions between the perylene probe and BPs, which can be further regulated by the introduction of a protease. Thus, the protease activity can be monitored by detecting the fluorescence intensity changes of probe 1. The method is label free, sensitive and selective. As low as 1 ng/mL trypsin can be easily detected. Graphical abstract fx1 Highlights • Black phosphorus nanosheets were used as the quencher for a fluorometric assay. • A label-free method for protease detection and inhibitor screening. • Histone controlled interactions between a perylene probe and black phosphorus nanosheets were used for signal transduction. • No covalent modifications were needed, and the assay is simple, sensitive and selective. [ABSTRACT FROM AUTHOR]

Highlights • A ratiometric nanosensor based on excimer and phosphorescence dual emission is constructed for the first time. • The nanosensor displays excellent sensitivity and selectivity against highly reactive oxygen species (hROS). • The ratiometric approach can significantly reduce the possible background interference in a complex biological environment. • Successful hROS imaging in live cells is demonstrated. Abstract A ratiometric nanosensor for the selective detection and intracellular imaging of highly reactive oxygen species (hROS) is developed. Benzoperylene probe and Mn-ZnS quantum dots based nanoparticles were fabricated through cost effective and simple procedures. The nanoparticles exhibit distinct excimer emission and long-lived room-temperature phosphorescence (RTP) emission at the same time under single wavelength excitation. The nanosensor shows highly sensitive and selective ratiometric response towards hROS over other ROS. The dual emission property also endows the nanoparticles the capability for sensitive live cell imaging of hROS, and the potential for real time monitoring of intracellular hROS. [ABSTRACT FROM AUTHOR]

Abstract In this work, we report a novel sensor for colorimetric and fluorometric H 2 O 2 sensing which is based on silver nanoparticles decorated and tetraphenylethene probe doped silica nanoparticles (Ag@TPE-SiO 2 NPs). A positively charged tetraphenylethene (TPE) probe is doped into silica nanoparticles, and the nanoparticles exhibit strong fluorescence emission due to aggregation-induced emission (AIE) of the TPE probe. Ag nanoparticles (AgNPs) are prepared in situ on the surface of the silica nanoparticles. AgNPs serve as a nanoquencher which can quench the AIE emission of the TPE-SiO 2 NPs efficiently. However, AgNPs can be oxidized to Ag+ by H 2 O 2 , which leads to fluorescence recovery and color fading of the Ag@TPE-SiO 2 NPs. The dual-readout strategy allows sensitive analysis of H 2 O 2. The detection limit of the fluorometric and colorimetric assay is 0.28 and 2.1 μM, respectively. And the nanosensor also shows good selectivity. In addition, analysis of H 2 O 2 in human serum and intracellular imaging of H 2 O 2 are both demonstrated. With the good analytical properties of merit, the proposed nanoprobe has a promising potential for H 2 O 2 related bioanalysis and biomedical applications. Graphical abstract fx1 Highlights • A sensor based on AgNPs decorated and TPE probe doped silica NPs was fabricated. • This dual-mode colorimetric and fluorometric sensor was employed for H 2 O 2 sensing. • The determination of H 2 O 2 in human serum was demonstrated. • The nanosensor was successfully employed for intracellular imaging of H 2 O 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fluorescent probe showed superior fluorescence enhancement based sensing performance for H 2 O 2 with a LOD of 10 nM. • A unique sensing approach based on geometry dependent restrictions in probe's intramolecular vibrations is proposed. • Sensing mechanism was elaborated through DFT calculations and 1H NMR titration. • Probe displayed great potential for H 2 O 2 vapors and determination of H 2 O 2 in real samples. Hydrogen peroxide (H 2 O 2) is a harmful chemical used as a signature compound in forming easily synthesizable peroxide-based explosives. Therefore, detecting H 2 O 2 vapors and solutions is imperative to avoid terroristic activities. Aggregation induced emission enhancement (AIEE) active probe PAT detected H 2 O 2 based on geometry-dependent hydrogen bonding. Unlike frequently reported fluorescent probes, probe PAT exhibited a strong fluorescence emission enhancement response for H 2 O 2 due to restrictions in intramolecular vibrations of probe. This unique sensing phenomenon enhances our probe's versatility and potential applications in the selective and sensitive detection of H 2 O 2. 1H NMR titration experiments and extensive density functional theory (DFT) calculations explained the distinct sensing mechanism. As a result of efficient interaction, probe could detect H 2 O 2 with critical features of excellent selectivity, nanoscale level detection (LOD; 10 nM), fast response (20 sec.), and distinguished photostability. Conveniently, probe PAT -embedded fluorescent strips were successfully employed as a portable sensing tool for rapidly recognizing H 2 O 2 vapors. Moreover, probe PAT was also capable of H 2 O 2 determination in industrial water, orange juice, milk samples and commercially available products. Therefore, our probe holds promising features for trace detection of H 2 O 2 in vapor and solution phase that make it highly useful. [ABSTRACT FROM AUTHOR]

[Display omitted] • New triphenylamine based sensor TTU was synthesized that exhibited reversible mechanochromic character. • Sensor was successfully employed for the sequential detection of iron (Fe3+) and deferasirox (DFX) • Sensor TTU displayed colorimetric and fluorometric detection of Fe3+. • Sensor was utilized for rapid recognition of Fe3+ and DFX in real samples. • Non-covalent interaction was investigated by 1H NMR titration and DFT studies. A novel triphenylamine (TPA) based sensor TTU was rationally designed and synthesized that exhibited reversible mechanochromic and aggregation induced emission enhancement (AIEE) properties. The AIEE active sensor was employed for fluorometric detection of Fe3+ in aqueous medium, with distinguished selectivity. The sensor showed a highly selective quenching response towards Fe3+ that is ascribed to complex formation with paramagnetic Fe3+. Subsequently, TTU -Fe3+ complex acted as a fluorescence sensor for the detection of deferasirox (DFX). The subsequent addition of DFX to TTU -Fe3+ complex led to the recovery of fluorescence emission intensity of sensor TTU that was attributed to the displacement of Fe3+ by DFX and release of sensor TTU. The proposed sensing mechanisms for Fe3+ and DFX was confirmed through 1H NMR titration experiment and DFT calculations. Frontier molecular orbitals (FMO), density of states (DOS), natural bond orbital (NBO), non-covalent interaction (NCI) and electron density difference (EDD) analysis were performed using DFT calculations to support the experimental results. Moreover, sensor TTU displayed colorimetric detection of Fe3+. Further, the sensor was employed for the detection of Fe3+ and DFX in real water samples. Finally, logic gate was fabricated by using sequential detection strategy. [ABSTRACT FROM AUTHOR]

[Display omitted] • A TPA based sensor was successfully synthesized which exhibited aggregation induced emission enhancement (AIEE) property. • The AIEE active sensor displayed selective and sensitive quenching response towards 4-NP. • The excellent selectivity of sensor against 4-NP was ascribed to PET process. • The sensor was successfully employed for detection of 4-NP in real water samples. • Extensive DFT studies were performed that supported non-covalent interaction. A triphenylamine (TPA) based fluorescent sensor T-TPA was elaborately designed which exhibited high quantum yield (QY). The sensor T-TPA displayed aggregation induced emission enhancement (AIEE) character that was confirmed by dynamic light scattering (DLS) analysis. The AIEE active π-electron rich sensor bearing thiourea moiety was employed for the detection of 4-nitrophenol (4-NP) in solution as well as vapor phase. In solution, sensor displayed fluorescence "turn-off" response towards 4-NP that was attributed to photoinduced electron transfer (PET). The quenching response of sensor T-TPA against 4-NP was highly selective even in the presence of higher concentration of interferences. The mechanistic approach for 4-NP sensing was confirmed through 1H NMR titration experiment, UV– Vis absorption spectroscopy, dynamic light scattering (DLS), and density functional theory (DFT) methodologies. Moreover, non-covalent interaction (NCI) and Bader's quantum theory of atoms in molecules (QTAIM) analysis was performed to support the presence of non-covalent interactions. Furthermore, the sensor was employed for the detection of 4-NP in industrial waste and lake water samples. Additionally, sensor coated paper strips were prepared to do the contact mode detection of 4-NP. Finally, the fluorescence quenching response of sensor was used for the fabrication of logic gate. [ABSTRACT FROM AUTHOR]

We report benzo[ghi]perylene (BzP) and coronene (Cron) as multimode fluorescent probes for accurate monitoring and direct visualization of monomer–micelle transitions in surfactants for the first time. The probe molecules formed self-assembled nanoparticles in an aqueous solution and displayed strong aggregation-enhanced excimer emission (AEEE). During the process of surfactant monomer–micelle transition, the probe nanoparticles dissolved, and the observation of excimer–monomer emission transition clearly indicated the formation of micelles. The ratiometric changes in excimer–monomer emission (IE/IM) were used for the precise determination of critical micelle concentration (CMC) of various surfactants. The monomer–micelle transition process was directly observed under a UV lamp, and the visual determination of CMC became possible. The CMC value determination using the excimer/monomer ratio (IE/IM), UV-vis, lifetime and visual assessment clearly suggests that BzP and Cron are excellent multimode probes for monitoring the micelle structural transitions of amphiphiles. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (Ag NPs) enhanced perylene probe excimer emission is reported for the first time. It was observed that strong interactions between the perylene probe and the Ag NPs induced co-aggregation. As a result, a new in situ generated plasmonic absportion band of the Ag NPs at longer wavelength emerged. The monomer emission of the perylene probe was efficiently quenched, and dramatically enhanced probe excimer emission was observed. A remarkable emission enhancement of over 1000 fold was obtained compared to anionic polymers and other nanoparticles. The excimer emission intensity could be finely modulated by the size of the Ag NPs and the functionalities of the perylene probe. The observed Ag NPs enhanced perylene probe excimer emission shows good potential for the development of novel sensing techniques for various bioanalytical applications. [ABSTRACT FROM AUTHOR]

Benzo[ghi]perylene and coronene were used as ratiometric fluorescent probes to monitor microenvironment changes and monomer-micelle transition for the first time. The perturbations in vibronic bands in the emission spectra of probes displayed microenvironment sensing behavior in various solvents and surfactants. The monomer–micelle transitions of anionic, cationic and neutral surfactants were monitored by changes in the ratios of vibronic band intensities. Clear CMC values were obtained, which is an advantage over the conventional probes such as pyrene with clear CMC values sometimes difficult to obtain due to less steep changes of S-shaped plots. They revealed a redshift in emission which offers a good substitute in situations where the fluorescence of pyrene and the background fluorescence of the assay mixture interfere with each other. BzP exhibited reverse behavior in the perturbations of vibronic band intensities in anionic SDS and SLS relative to cationic and non-ionic surfactants, which was not observed when pyrene was used. In addition, the vibronic band ratios of BzP are thermally more stable than those of pyrene, which is advantageous since strict assay temperature control may not be necessary. These probes are thus helpful for various applications in the areas of sensing and interface science. [ABSTRACT FROM AUTHOR]

New regioisomerically pure green and blue dyes i.e . 1,7 and 1,6 piperidine substituted perylenebisimides ( 1A , 1B , 2A , 2B ) were synthesized. Photophysical properties were compared with unsubstituted and brominated perylenebisimide analogues ( 1 , 1PBr 2 , 2, 2PBr 2 ). Piperidine was substituted on the bay region after imidization of dibromoperylene-3,4,9,10-tetracaboxylic dianhydride which induces strong bathochromic shifts. Large bathochromic shifts lower the optical band gaps which is the key feature of NIR absorbing fluorescent dyes with improved photovoltaic efficiencies. All synthesized fluorophores were characterized by NMR and Mass spectrometry. Photophysical properties were evaluated by UV–Vis, fluorimetry, and cyclic voltammetry. Fluorescence quantum yields were estimated by adopting a gradient method. The well-defined sharp peaks in X-ray diffraction pattern confirmed the crystalline nature of 1A and 1B . In contrast 2A and 2B were found non-crystalline. Thermal analysis by TG-DSC further explored the stability and phase transitions in dyes. HOMO and LUMO molecular orbitals were depicted by using density functional theory (DFT) at B3LYP/6–31(d,p). Electrochemical behaviors probed by cyclic voltammogram revealed dominant reversible oxidation reactions for 1,7 regioisomers ( 1A , and 2A ) while both reversible oxidations and reductions were observed in 1,6 isomers ( 1B and 2B ). Other structural analogues 1 , 1PBr 2 , 2 , 2PBr 2 displayed reversible reductions. Thus a regular trend of changes in optical and electrical properties was observed on bromine and piperidine substitution. The observed outstanding properties clearly justify that our compounds might be promising candidates for various future applications such as biosensors, biomarkers, semiconductors, charge transporters, and stable fluorescent dyes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Easily synthesizable thiourea functionalized probes SH1 and SH2 were used for the detection of ClO−. • Nanoscale detection of ClO− was achieved through desulfurization reaction of probes. • Blue shift (≥100 nm) in the fluorescence emission of probes after addition of ClO− evidently supports the chemical change. • Probe SH1 displayed excellent response towards ClO− in biological system and blood serum. • Probes coated fluorescent films were fabricated. Being one of the vital reactive oxygen species (ROS), abnormal level of hypochlorite ion (ClO−) may pose detrimental threats to living organisms. Therefore, highly selective, and rapid monitoring of ClO− in living system is of prime importance to protect living organisms from its harmful effects. In this regard, design of synthetic fluorescent probes for ClO− has garnered considerable attention. However less fluorescence emission in aggregated state and less photostability of several existing probes for ClO− inspired us to design aggregation induced emission (AIE) active fluorescent probes SH1 and SH2. Probes were rationally designed by introducing thiourea moiety that selectively reacted through desulfurization reaction and resulted in highly selective detection of ClO−. Hypochlorite induced desulfurization reaction was validated through 1H NMR titration and DFT studies. Fine tuning of probes SH1 and SH2 prompted highly sensitive nanoscale (55 nM and 77 nM) and rapid (15 and 35 sec) detection of ClO−. Probe SH1 displayed less cytotoxic effect to live cells before it was successfully applied for bioimaging of ClO− in live MCF-7 cells. Moreover, probes displayed excellent sensing potential for ClO− in blood serum and real water samples. Advantageously, probe coated portable fluorescent films were fabricated for the easy and fast monitoring of ClO−. Of note, this work offers excellent design strategy for highly selective detection of ClO− that may lead to clinical trials. [ABSTRACT FROM AUTHOR]

Based on the controlled aggregation of quantum dots (QDs), a valid, reliable, and label-free fluorescence turn-on strategy is established for the detection of alkaline phosphatase activity. The aqueous solution of anionic QDs exhibits intense fluorescence. However, the addition of cationic polymer (poly-1) significantly quenched the fluorescence of the QDs via their induced aggregation. While short 3′-phosphorylated DNA (DNA-P) could not be extended by terminal deoxynucleotidyl transferase (TdT) and therefore, fluorescence of the QDs was recovered negligibly. The effective elimination of phosphate group of DNA-P in the presence of alkaline phosphatase (ALP) produced 3′-OH termini and the resulting DNA could be sufficiently extended by TdT. The presence of greater binding strength between the elongated DNA and poly-1 is very crucial to compete with the poly-1/QDs aggregates and release the QDs. Turned-on fluorescence emission is observed due to the efficient release of the QDs. A novel strategy for alkaline phosphatase detection is therefore established. Our method is quite sensitive and selective, as low as 0.1 mU/mL ALP can be easily detected. [ABSTRACT FROM AUTHOR]

Our aim was to develop a biocompatible hydrogel that could be soaked in heparin and placed on wound beds to improve the vasculature of poorly vascularized wound beds. In the current study, a methodology was developed for the synthesis of a new chitosan derivative (CSD-1). Hydrogels were synthesized by blending CSD-1 for either 4 or 24 h with polyvinyl alcohol (PVA). The physical/chemical interactions and the presence of specific functional groups were confirmed by Fourier transform infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance ( 1 H NMR). The porous nature of the hydrogels was confirmed by scanning electron microscopy (SEM). Thermal gravimetric analysis (TGA) showed that these hydrogels have good thermal stability which was slightly increased as the blending time was increased. Hydrogels produced with 24 h of blending supported cell attachment more and could be loaded with heparin to induce new blood vessel formation in a chick chorionic allantoic membrane assay. [ABSTRACT FROM AUTHOR]

A cancer cell specific aptamer was labeled with an aggregation-induced emission (AIE) probe for the first time. Using it as a light-up bioprobe, a specific cancer cell detection method is developed. [ABSTRACT FROM AUTHOR]

In this study, a novel approach is adapted for the synthesis of new nanostructures of cobalt oxide (Co3O4) by low temperature aqueous chemical growth method in the presence of water soluble amino acids such as L-arginine, L-aspartic acid, L-isoleucine, L-leucine, L-serine and L-threonine. The synthesized nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The nanostructures exhibit well defined morphology and are of high purity. To explore the potential application of the prepared nanostructures of cobalt oxide, the non-enzymatic glucose sensor is developed by modifying the glassy carbon electrode. Serine assisted cobalt oxide nanostructures showed excellent sensitivity of 4169.00 μA/mM cm2, wide linear range of 0.01 mM to 20 mM and detection limit was estimated as 0.001 mM (S/N=3). The analytical parameters for the serine assisted cobalt oxide nanostructures based glucose sensor were evaluated and it was found that the sensor is highly selective, reproducible, repeatable, reversible, and stable. Finally, the practical application of the serine assisted cobalt oxide nanostructures based glucose sensor was examined by measuring the glucose concentrations from real human blood samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two fluorescent probes were developed for the detection of hypochlorite (ClO−) with detection limit down to nanomolar (nM). • Different sensing mechanisms were involved based on the structural attributes of probes. • Probe 1 was successfully employed for the monitoring of exogenous ClO− in food and environmental samples. • Probe 1 coated paper strips provided portable method for solid supported detection of ClO−. Being one of the important reactive oxygen species (ROS), hypochlorite ions (ClO−) are involved in the control of several pathological and physiological processes. However, overexpression of ClO− may prompt several disorders including cancer. Therefore, two fluorescein functionalized compounds with catechol (probe 1) and 2-naphthyl (probe 2) as substituents were synthesized through Schiff base reaction to recognize ClO− in food items and industrial samples. While probe 2 exhibited turn-off fluorescent response towards ClO− with limit of detection (LOD) of 86.7 nM, structurally alike probe 1 showed excellent ratiometric response with low detection limit (36.3 nM), large Stokes shift (353 nm), and 'fast' response time (15 s). 1H NMR titration experiments favored spiroring opening of probe 1 upon the reaction with ClO−. Probe 1 was successfully utilized for the monitoring of exogenous ClO− in industrial samples. Further, fabrication of probe coated fluorescent paper strips and recognition of ClO− in sprouting potato show diverse practical applicability of our probes. [ABSTRACT FROM AUTHOR]