A quick accelerating microwave-assisted sustainable technique: permutated spiro-casing for imaging experiment.

A quick access tool for the one-pot, chromatography-free synthesis of the diversified dihydrospiro[indeno[1,2-b]pyridine-4,3'-indoline or acenaphthylene-1,4'-indeno[1,2-b]pyridine spiro-analogous via sustainable microwave condition in minimal 1:1 (v/v) aqueous ethanol without any metal catalyst is demonstrated here. This permutated spiro-casing was designed as fluorescence probe at physiological pH for selective detection of Zn2+, even in the presence of other competitive ions and showed a fluorescent enhancement with 1:1 metal/ligand complex. Moreover, this spiro sensor was successfully applied as an effective intracellular Zn2+ imaging agent in the biomedical study of human hepatocellular liver carcinoma cells (HepG2) due to its cell permeability property. A quick access technique for the permutated dihydrospiro-pyridine via chromatography-free sustainable microwave condition and its applications as organic fluorescence probe at physiological pH for selective detection of Zn2+ and effective intracellular Zn2+ imaging in HepG2 cells.

Solvent-Dependent Nanostructures Based on Active π-Aggregation Induced Emission Enhancement of New Carbazole Derivatives of Triphenylacrylonitrile.

In the present study, the carbazole and 2,3,3-triphenylacrylonitrile (TPAN) nanostructures (2-CTPAN and 2,2'-CTPAN) have been designed and synthesized by Pd-catalyzed Sonogashira cross-coupling reaction. CTPAN exhibit aggregation-induced emission enhancement (AIEE) behavior in water with high fluorescence quantum yield. Both the compounds show tunable self-assembly in water as well as in N,N-dimethylformamide (DMF) by extended π-π stacking interactions. CTPAN can be self-assembled into spherical particles in water and the structures of these self-assemblies have been investigated using X-ray diffraction. Interestingly, 2-CTPAN and 2,2'-CTPAN form organogels with a critical gelation concentration (CGC) of 11 and 15 mg mL-1 , respectively, in DMF and exhibit acicular and rod shaped morphology, respectively. The single-crystal structure of 2-CTPAN shows that the intermolecular C-H⋅⋅⋅π interactions lock the molecular conformation into a staircase-shaped supramolecular assembly. These AIEE active compounds reveal high water dispersibility, strong yellow fluorescence with high quantum yield, promising photostability and excellent biocompatibility, which make them potential bioimaging agents.

Aggregation-Induced Emission-Based Sensing Platform for Selective Detection of Zn2+ : Experimental and Theoretical Investigations.

Fluorescent chemosensors with aggregation induced emission enhancement (AIEE) emerge as promising tools in the field of sensing materials. Herein, we report the design, synthesis and applicability of a Schiff base chemosensor 1-(benzo[1,3]dioxol-4-ylmethylene-hydrazonomethyl)-naphthalen-2-ol (Hbdhn) of AIE characteristics that exhibits highly effective and selective response towards Zn2+ . The sensing effect of Hbdhn was evaluated by means of absorption/emission spectra and corresponding underlying photophysical mechanisms were proposed based on extensive quantum-chemical (TD)DFT calculations. The aggregated states in different DMSO/H2 O ratios and in a presence of Zn2+ were examined by fluorescence lifetime measurements, dynamic light scattering and scanning electron microscopy studies. The bioimaging abilities of Hbdhn were evaluated for Zn2+ in HepG2 cancer cells. The results demonstrate instant, stable in time and reproducible, colorimetric turn-on response with superb selectivity and sensitivity of Hbdhn towards Zn2+ , based on chelation enhanced fluorescence mechanism. AIEE improves further Hbdhn properties, leading to strong, long-lived fluorescence, with appearance of rod-like particles, in 90 % of water in DMSO and only 10 % of water in DMSO in the presence of Zn2+ . All these features combined with successful biomaging studies make Hbdhn one of the most promising candidate for practical applications among recently proposed related systems.

Oral submucous fibrosis: A global challenge. Rising incidence, risk factors, management, and research priorities.

Oral submucous fibrosis is a potentially malignant disorder of the oral cavity, with a high rate of malignant transformation. It is very common among habitual areca nut chewers. The pathogenesis of oral submucous fibrosis is not well established, but it is believed to be a disease of multifactorial origin, including areca nut chewing, ingestion of chilies, genetic factors, immunologic processes and nutritional deficiencies. Genetically susceptible individuals when exposed to areca nut chewing develop this disease over a variable period of time. Oral submucous fibrosis is considered to be a disease of collagen metabolism. Several genetic factors are reported but there is no consensus about the exact mechanism of disease initiation. Variations in histopathological presentation are noted among oral submucous fibrosis patients with habitual areca nut chewing in different forms and other additive agents, eg betel quid, pan masala and gutkha, together with a variety of tobacco habits. The role of epigenetic modifications, such as miRNA regulation, and DNA methylation is also being reported as part of the pathogenesis of oral submucous fibrosis. A combined approach, including analysis of genetic and epigenetic regulations with different habits, might be helpful to better understand the contributory factors and pathogenesis of this serious disorder.

Identification of over expressed proteins in oral submucous fibrosis by proteomic analysis.

Early detection and identification of oral pre-malignancy or malignancy help in management of the disease and improve survival rates. Oral submucous fibrosis (OSMF) is a major threat to public health worldwide and especially in Southeast Asian countries. Identification of biomarkers is a necessary step toward early diagnosis and treatment. In this study, differentially expressed proteins between oral submucous fibrotic tissue and normal control tissues were recorded by proteomic analysis using two dimensional electrophoresis (2DE) and MALDI TOF mass spectrometry. By proteomic analysis, 15 proteins were found to be upregulated and 10 proteins downregulated in the OSMF tissues than the control tissues; among these identified proteins, Hsp-70 1B, Calreticulin, and Lumican variant exhibited higher expression in OSMF tissues compared to the control tissues. Immunohistochemical analysis also showed elevated expression of these in OSMF tissues. Further validation was done by real time quantitative RT-PCR analysis; gene expression of Hsp-70 1B, Calreticulin, and Lumican variant were significantly increased (6.2-, 3.3-, 2.8- fold, respectively), whereas Enolase 1 was decreased by 0.5 fold in the OSMF tissues, consistent with proteomic results. The expression of proteins indicates that various cellular signaling pathways must be involved in the processes of fibrosis and suggests that expressed protein molecules play an important role in the pathogenesis of OSMF. These identified proteins may be potentially used in future studies of OSMF enabling to determine diagnostic marker or therapeutic targets of this precancerous condition of oral cavity.

A hydrazone based probe for selective sensing of Al(iii) and Al(iii)-probe complex mediated secondary sensing of PPi: framing of molecular logic circuit and memory device and computational studies.

A hydrazone-based conjugate Nap-hyz-pyz (H3L3) with potential N2O2 donor atoms was found to act as a dual channel (colori- and fluori-metric) sensor towards Al3+ and PPi in H2O-MeOH (6 : 4, v/v) at pH 7.2 (40 mM HEPES buffer) at 25 °C. The formation constants, Kf = (3.49 ± 1.77) × 104 and (3.78 ± 0.1) × 104 M-1, of the sensor towards Al3+ were determined by absorption and fluorescence titrations, respectively. The 1 : 1 stoichiometry of the reaction was determined by Job's method and confirmed by ESI-MS+ (m/z) studies. The LOD for Al3+, as determined by the 3σ method, was found to be 114.54 nM. Most strikingly, the addition of ∼115 µM PPi to the Nap-hyz-pyz-Al3+ ensemble (20 µM ligand and 74 µM Al3+) leads to complete quenching of fluorescence. The fluorescence response of Nap-hyz-pyz towards Al3+ was not perturbed by the presence of 5 equivalents or more of other ions and inorganic anions. The structure of the [Al(L3)(H2O)] complex was delineated by DFT calculations. TD-DFT studies were performed to investigate various spectral transitions. Based on changes in the fluorescence intensities of Nap-hyz-pyz in the presence of Al3+ and PPi at 487 nm, INHIBIT and molecular logic gates were constructed and interpreted. The probe was found to be bio-compatible and cell permeable with no or negligible cytotoxicity; thus, it provides a good opportunity for in vitro cell imaging studies of these ions. The presence of ATP or Pi did not interfere with the fluorescent detection of PPi. Thus, these evident and excellent sensing capabilities of Nap-hyz-pyz towards Al3+ and PPi were further scrutinized in HepG2 cell lines.

Dihydroindeno[1,2-b]pyrroles: new Al3+ selective off-on chemosensors for bio-imaging in living HepG2 cells.

In this study, a new molecular organic probe has been designed and synthesized by using recyclable, inexpensive and non-toxic polyethylene glycol (PEG-400) as a promoting reaction medium in water under environmentally benevolent conditions. The probe has been explored as a potential chemosensor to detect Al3+ ions using a HEPES buffer (pH = 7.4) solution. Investigations of the fluorescence behaviour of this sensor in DMSO/H2O (2 : 8, v/v) solution displayed a dramatic switch-on response only in the presence of Al3+, while other metal ions, like Li+, Na+, K+, Ag+, Ca2+, Mg2+, Mn2+, Ba2+, Cu2+, Ni2+, Co2+, Fe2+, Zn2+, Cd2+, Hg2+, Pb2+, Sr2+, Fe3+ or Cr3+, have almost no influence on the fluorescence behaviour. Various common anions, such as ClO4-, Cl-, or NO3- in the form of Al3+ salts [e.g. Al(ClO4)3, AlCl3 or Al(NO3)3], had no influence on the fluorescence behaviour of the sensors. The detection limit for Al3+ is in the order of 10-6 M in DMSO/H2O (2 : 8, v/v) HEPES buffer (pH = 7.4) solution. Notably, this is the first report of a dihydroindeno[1,2-b]pyrrole moiety acting as a sensor for the selective detection of Al3+ ions through an off-on fluorescence response. The potential of the probe was also confirmed by employing it for fluorescence bio-imaging with Al3+ on HepG2 cells.

I2 catalyzed access of spiro[indoline-3,4'-pyridine] appended amine dyad: new ON-OFF chemosensors for Cu2+ and imaging in living cells.

An easy access to an amine-appended spiro[indoline-3,4'-pyridine] ON-OFF chemosensor by a one-pot four-component reaction using commercially available and an environmentally benign catalytic amount of molecular I2 (10 mol%) in aqueous ethanol at ambient temperature is described. The generated system could be utilized for the selective detection of Cu2+ as it demonstrated a colorimetric naked eye change along with an ON-OFF fluorescence response towards Cu2+ at physiological pH. The sensors exhibited high selectivity for Cu2+ over other common cations with detection limit in the range of 10-7 (M). Notably, this is the first report of a spiro[indoline-3,4'-pyridine] moiety acting as a sensor for Cu2+via a on-off fluorescence response. In addition, the probe system was successfully applied for imaging Cu2+ in human hepatocellular liver carcinoma cells (HepG2), demonstrating a new avenue for molecular imaging and biomedical applications.

A benzimidazole-based chemodosimeter for the fluorometric detection of Zn and Cu via 1,5 proton shifts and C-N bond cleavage.

Here, we report the design and synthesis of the fluorescent probe APBHN, which was derived from 2-(1H-benzo[d]imidazol-2-yl)benzenamine and is capable of detecting intracellular Zn and Cu ions in the micromolar range. Single-crystal X-ray analysis revealed that the structure of the ligand comprises a fused cyclic system with a pendent naphthol moiety. With the addition of Zn and Cu ions the inherent fluorescence behaviour of the ligand APBHN is perturbed via a chemodosimetric change that involves a 1,5 proton shift followed by C-N bond cleavage. Upon detailed analysis, it was found that the ligand forms 1 : 1 and 1 : 2 (metal to ligand) complexes with the corresponding metal ions. The detection limits of Zn2+ and Cu2+ were 5.59 µM and 0.148 µM, respectively, with APBHN, which are lower than the WHO guidelines (76 µM for Zn2+ and 31.5 µM for Cu2+) for drinking water. Moreover, APBHN could be used as a practical, visible colorimetric test kit for both Zn2+ and Cu2+. APBHN can efficiently detect Zn2+ and Cu2+ in liver carcinoma cells with insignificant cytotoxicity.

A Smart Molecule for Selective Sensing of Nitric Oxide: Conversion of NO to HSNO; Relevance of Biological HSNO Formation.

A smart molecule, QT490, containing thiosemicarbazide moiety acts as a highly selective turn-on in vitro NO sensor through the unprecedented NO-induced transformation of thiosemicarbazide moiety to 1,3,4-oxadiazole heterocycle with the concomitant release of HSNO, thereby eliminating any interference from various endogenous biomolecules including dehydroascorbic acid, ascorbic acid, etc. The kinetic studies of the reactions between QT490 and NO provide a mechanistic insight into formation of HSNO/RSNO from the reaction between H2S/RSH and NO in the biological system. This novel probe is non-cytotoxic, cell permeable, water-soluble, and appropriate for intracellular cytoplasmic NO sensing with the possibilities of in vivo applications.

Expedient synthesis of a phenanthro-imidazo-pyridine fused heteropolynuclear framework via CDC coupling: a new class of luminophores.

We herein report the design and synthesis of a group of fused phenanthro-imidazo[1,2-a]pyridine derivatives as a new class of luminescent materials through a Pd(ii) catalyzed intramolecular CDC (cross dehydrogenative coupling) reaction. This method thus unlocked a convenient & expedient way for the synthesis of a new molecular framework containing π-extended fused heteropolycycles. The heteropolycycles showed very good fluorescence properties both in solid and solution phases which were further utilized in live cell imaging. These kinds of molecules have potential to be used as therapeutic probes and also their solid state luminescence properties can be further utilized for making optoelectronic devices.

Neo-tanshinlactone D-ring modified novel analogues induce apoptosis in human breast cancer cell via DNA damage.

Neo-tanshinlactone (NTL) a natural product is known for its specificity and selectivity towards the breast cancer cells. By NTL D-ring modification approach, 13 new analogues were synthesized (1A-1M). Among them 1J showed the best anticancer activity in MCF-7 (ER+, PR+/-, HER2-), SKBR3 (ER-, PR-, HER2+) and MDA-MB-231 (ER-, PR-, HER2-) cells lines with IC50 value 11.98nM, 23.71nM, and 62.91nM respectively. 1J showed minor grove binding interaction with DNA at AT-rich region and induced DNA double strand breaks (DDSBs). This had triggered several key molecular events involving, activation of ATM, Chk2 and p53, reduction in mitochondrial potential (Δψm) leading to caspase-3 and PARP cleavage mediated apoptosis. These results along with other biochemical studies strongly suggest that novel NTL analogue 1J caused DNA cleavage mediated apoptosis in the breast cancer cells and this may serve as potential lead for future breast cancer treatment.

Surfactant modulated aggregation induced enhancement of emission (AIEE)--a simple demonstration to maximize sensor activity.

A new type of easily synthesized rhodamine-based chemosensor L(3), with potential NO2 donor atoms, selectively and rapidly recognizes Hg(2+) ions in the presence of all biologically relevant metal ions and toxic heavy metals. A very low detection limit (78 nM) along with cytoplasmic cell imaging applications with no or negligible cytotoxicity indicate good potential for in vitro/in vivo cell imaging studies. SEM and TEM studies reveal strongly agglomerated aggregations in the presence of 5 mM SDS which turn into isolated core shell microstructures in the presence of 9 mM SDS. The presence of SDS causes an enhanced quantum yield (φ) and stability constant (Kf) compared to those in the absence of SDS. Again, the FI of the [L(3)-Hg](2+) complex in an aqueous SDS (9 mM) medium is unprecedentedly enhanced (∼143 fold) compared to that in the absence of SDS. All of these observations clearly manifest in the enhanced rigidity of the [L(3)-Hg](2+) species in the micro-heterogeneous environment significantly restricting its dynamic movements. This phenomenon may be ascribed as an aggregation induced emission enhancement (AIEE). The fluorescence anisotropy assumes a maximum at 5 mM SDS due to strong trapping (sandwiching) of the doubly positively charged [L(3)-Hg](2+) complex between two co-facial laminar microstructures of SDS under pre-miceller conditions where there is a strong electrostatic interaction that causes an improved inhibition to dynamic movement of the probe-mercury complex. On increasing the SDS concentration there is a phase transition in the SDS microstructures and micellization starts to prevail at SDS ≥ 7.0 mM. The doubly positively charged [L(3)-Hg](2+) complex is trapped inside the hydrophobic inner core of the micelle which is apparent from the failure to quench the fluorescence of the complex on adding 10 equivalents of H2EDTA(2-) solution but in the absence of SDS it is quenched effectively.

6-Gingerol inhibits Vibrio cholerae-induced proinflammatory cytokines in intestinal epithelial cells via modulation of NF-κB.

Context The effect of 6-gingerol (6G), the bioactive component of Zingiber officinale Roscoe (Zingiberaceae), in the reduction of Vibrio cholerae (Vibrionaceae)-induced inflammation has not yet been reported. Materials and methods Cell viability assay was performed to determine the working concentration of 6G. Elisa and RT-PCR were performed with Int 407 cells treated with 50 µM 6G and 100 multiplicity of infection (MOI) V. cholerae for 0, 2, 3, 3.5, 6 and 8 h to determine the concentration of IL-8, IL-6, IL-1α and IL-1ß in both protein and RNA levels. Furthermore, the effect of 50 µM 6G on upstream MAP-kinases and NF-κB signalling pathways was evaluated at 0, 10, 15, 30, 60 and 90 min. Results The effective dose (ED50) value of 6G was found to be 50 µM as determined by cell viability assay. Pre-treatment with 50 µM 6G reduced V. cholerae infection-triggered levels of IL-8, IL-6, IL-1α and IL-1ß by 3.2-fold in the protein level and two-fold in the RNA level at 3.5 h. The levels of MAP-kinases signalling molecules like p38 and ERK1/2 were also reduced by two- and three-fold, respectively, after 30 min of treatment. Additionally, there was an increase in phosphorylated IκBα and down-regulation of p65 resulting in down-regulation of NF-κB pathway. Conclusion Our results showed that 6G could modulate the anti-inflammatory responses triggered by V. cholerae-induced infection in intestinal epithelial cells by modulating NF-κB pathway.

De novo design based pharmacophore query generation and virtual screening for the discovery of Hsp-47 inhibitors.

Heat shock protein-47 (Hsp-47) is exclusive collagen specific molecular chaperone involved in the maturation, processing and secretion of procollagen. Hsp-47 is consistently upregulated in several fibrotic diseases. Till date there is no potential antifibrotic small molecule drug available and Hsp-47 is known to be potential therapeutic target for fibrotic disorder and drug designing. We used the de novo drug design approach followed by pharmacophore generation and virtual screening to propose Hsp-47 based antifibrotic molecules. We used e-LEAD server for de novo drug design and ZINCPharmer for 3D pharmacophore generation and virtual screening. The virtually screened molecule may inhibit direct recruitment of collagen triple helix to interact with Hsp-47 and act as antifibrotic drug.

Di-oxime based selective fluorescent probe for arsenate and arsenite ions in a purely aqueous medium with living cell imaging applications and H-bonding induced microstructure formation.

A 2-hydroxy-5-methyl-benzene-1,3-dicarboxaldehyde di-oxime based turn-on blue emission fluorescent probe was found to recognize both AsO2(-) and H2AsO4(-) in a purely aqueous medium in intra and extra-cellular conditions. Self-organization of the ligand in the absence and presence of AsO2(-) and H2AsO4(-) was investigated by DLS, optical microscopy, optical fluorescence microscopy and FE-SEM methods.

Vibrio cholerae O395 outer membrane vesicles modulate intestinal epithelial cells in a NOD1 protein-dependent manner and induce dendritic cell-mediated Th2/Th17 cell responses.

Like other Gram-negative pathogens, Vibrio cholerae, the causative agent of the diarrheal disease cholera, secretes outer membrane vesicles (OMVs). OMVs are complex entities composed of a subset of envelope lipid and protein components and play a role in the delivery of effector molecules to host cells. We previously showed that V. cholerae O395 cells secrete OMVs that are internalized by host cells, but their role in pathogenesis has not been well elucidated. In the present study, we evaluated the interaction of OMVs with intestinal epithelial cells. These vesicles induced expression of proinflammatory cytokines such as IL-8 and GM-CSF and chemokines such as CCL2, CCL20, and thymic stromal lymphopoietin in epithelial cells through activation of MAPK and NF-κB pathways in NOD1-dependent manner. Epithelial cells stimulated with OMVs activated dendritic cells (DCs) in a direct co-culture system. Activated DCs expressed high levels of co-stimulatory molecules; released inflammatory cytokines IL-1ß, IL-6, TNF-α, and IL-23 and chemokines CCL22 and CCL17; and subsequently primed CD4(+) T cells leading to IL-4, IL-13, and IL-17 expression. These results suggest that V. cholerae O395 OMVs modulate the epithelial proinflammatory response and activate DCs, which promote T cell polarization toward an inflammatory Th2/Th17 response.

Comparative evaluation of genotoxicity by micronucleus assay in the buccal mucosa over comet assay in peripheral blood in oral precancer and cancer patients.

Early detection and quantification of DNA damage in oral premalignancy or malignancy may help in management of the disease and improve survival rates. The comet assay has been successfully utilised to detect DNA damage in oral premalignant or malignancy. However, due to the invasive nature of collecting blood, it may be painful for many unwilling patients. This study compares the micronucleus (MN) assay in oral buccal mucosa cells with the comet assay in peripheral blood cells in a subset of oral habit-induced precancer and cancer patients. For this, MN assay of exfoliated epithelial cells was compared with comet assay of peripheral blood leucocytes among 260 participants, including those with oral lichen planus (OLP; n = 52), leukoplakia (LPK; n = 51), oral submucous fibrosis (OSF; n = 51), oral squamous cell carcinoma (OSCC; n = 54) and normal volunteers (n = 52). Among the precancer groups, LPK patients showed significantly higher levels of DNA damage as reflected by both comet tail length (P < 0.0001) and micronuclei (MNi) frequency (P = 0.0009). The DNA damage pattern in precancer and cancer patients was OLP < OSF < LPK < OSCC, and with respective oral habits, it was multiple habits > cigarette + khaini > cigarette smokers > areca + khaini > areca. There was no significant difference in the comet length and MNi frequency between males and females who had oral chewing habits. An overall significant correlation was observed between MNi frequency and comet tail length with r = 0.844 and P < 0.0001. Thus, the extent of DNA damage evaluation by the comet assay in peripheral blood cells is perfectly reflected by the MN assay on oral exfoliated epithelial cells, and MNi frequency can be used with the same effectiveness and greater efficiency in early detection of oral premalignant conditions.

A novel chromo- and fluorogenic dual sensor for Mg(2+) and Zn(2+) with cell imaging possibilities and DFT studies.

A diformyl-p-cresol (DFC)-8-aminoquinoline based dual signaling probe was found to exhibit colorimetric and fluorogenic properties on selective binding towards Mg(2+) and Zn(2+). Turn-on fluorescent enhancements (FE) as high as 40 fold and 53 fold in 9 : 1 MeCN/water (v/v) at pH 7.2 in HEPES buffer for Mg(2+) and Zn(2+), respectively, were observed. The binding constants determined from the fluorescence titration data are: K = (1.52 ± 0.21) × 10(5) M(-1) and (9.34 ± 4.0) × 10(3) M(-2) at n = 1 and 0.5, for Mg(2+) and Zn(2+), respectively. The L : M binding ratios were also determined by Job's method, which support the above findings. This is further substantiated by HRMS analysis. Due to solubility in mixed organo-aqueous solvents as well as cell permeability it could be used for the in vitro/in vivo cell imaging of Mg(2+) and Zn(2+) ions with no or negligible cytotoxicity. This probe could be made selective towards Mg(2+) over Zn(2+) in the presence of TPEN, both under intra- and extracellular conditions and is superior to other Mg(2+) probes which suffer from selectivity of Mg(2+) over Ca(2+) or Zn(2+). Furthermore the dissociation constant (Kd = 6.60 µM) of the Mg(2+)-() complex is far lower than the so far reported Mg(2+) probes which fall in the mM range.

Erratum to: Detection of a novel mutation in exon 20 of the BRCA1 gene.

[This corrects the article DOI: 10.2478/s11658-013-0110-3.].