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In this work, a novel organic receptor, CPI [( E )-3-(4-(9 H -carbazol-9-yl)phenyl)-2-(1 H -benzo[ d ]imidazol-2-yl)acrylonitrile], was rationally designed and successfully fabricated for selective and sole recognition of CN - ions over other competitive anions through an obvious chromogenic and ratiometric emission change in DMSO. The distinct and prominent color change upon the addition of CN - can be attributed to the typical ICT process, which is induced by the deprotonation of acidic NH protons in the imidazole moiety. The sensor displayed strong solvatochromic effects in commonly used organic solvents such as n -hexane, toluene, diethyl ether, DCM, THF, DMF and DMSO. The chemical structure of the sensor was characterized by single-crystal X-ray diffraction, 1 HNMR, 13 CNMR, IR and mass spectroscopy. Significantly, the probe can function as a fluorescence-based sensor for the efficient detection of low-level water in organic solvents. The solid-state emission properties of CPI were successfully applied to recognise cyanide in a solid-state platform with naked eye-visualized distinct color change. The probe can be made reusable by adding TFA into the CN - treated probe solution. The detection limit of CPI towards CN - was determined to be 4.48 × 10 -8 M. More importantly, the sensor is capable of detecting CN - in food samples and has been employed for wastewater treatment. Besides, easy-to-prepare CPI-coated test strips provide a simple, reusable and easy-to-handle protocol for the qualitative identification of CN - conveniently. Finally, density functional theory and time-dependent density functional theory were performed to verify the experimental outcomes theoretically.

Transdermal drug delivery is a viable and clinically proven route of administration. This route specifically requires overcoming the mechanical barrier provided by the Stratum Corneum of epidermis and vascular and nervous networks within the dermis. First-generation Transdermal patches and second-generation iontophoretic patches have been translated into commercial clinical products successfully. The current review reports different studies that aim to enhance the transdermal delivery of biopharmaceutical using microneedles and their effect on drug delivery. Microneedles (MN) are the micron-scale hybrid between transdermal patches and hypodermic syringes. Microneedles are tested and proven to show better delivery of the drugs, overcoming the drawbacks of hypodermic syringes. Multiple microneedles designs have been fabricated i.e. solid, coated, hollow, and polymer microneedles. Hollow microneedles are shorter in length but similar to hypodermic needles and have pore for infusion of liquid formulation of the drug. Solid microneedles a patch is applied after creating a hole in the skin; Drugs are coated on the surface of Coated microneedles; Polymer microneedles can be of different types like dissolving, non-dissolving or hydrogel-forming made up of polymers. Various advantages and limitations associated with the use of these techniques are discussed. Delivery of peptide and protein molecules with microneedles represents a significant opportunity for a better clinical outcome and hence value creation compared to standard injectable routes of administration. The advancement in various formulation and microfabrication techniques are currently being focused to aid the delivery of protein drugs via microneedles. The most recent advances and limitations in Microneedles -mediated protein and peptide delivery were discussed., (© 2021. Controlled Release Society.)

A new fluorescent "on-off-on" probe (BIPQ) is designed and developed which selectively binds with Hg 2+ ; its emission intensity is quenched almost 40-fold at 455 nm without interference from other metal cations. On gradual addition of I - to the solution of BIPQ-Hg 2+ , the emission reverts to its original intensity. The limits of detection of BIPQ for Hg 2+ and I - are found to be on the order of 3.12 × 10 -9 and 5.48 × 10 -8 M, respectively, which shows clearly that BIPQ can sense Hg 2+ at a very minute level. DFT and TDDFT studies are conducted with the probe to establish similarity between theoretical and experimental outcomes. Finally, to demonstrate its practical benefit in biological fields, live cell imaging experiments with BIPQ are carried out to detect Hg 2+ in human AGS gastric cancer cell lines.

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., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Background: Oxidative stress is common in type 2 diabetes. It is characterised by increased levels of reactive oxygen species (ROS), of which hypochlorous acid (HOCl) is an important component. Type 2 diabetes is characterised not only by hyperglycemia, but also by dyslipidemia. It probably underlies both the development of diabetes and also resulting complications, like cardiovascular disease. We applied a novel fluoroprobe RHQ to estimate endogenous HOCl and myeloperoxidase (MPO) activity in diabetes and dyslipidemia., Methods: Our newly designed probe, RHQ (rhodamine-quinoline based chemodosimeter) is capable of estimating endogenous HOCl selectively out of the ROS components. Isolated leukocytes from study subjects were treated with DCFDA and monocytes and neutrophils with RHQ for estimating endogenous ROS and HOCl respectively. Plasma AOPP, an indicator of HOCl was also measured. We attempted to find out the key reasons of higher HOCl content in diabetic dyslipidemic subjects by quantitating endogenous hydrogen peroxide (H2O2) and myeloperoxidase (MPO) activity., Results: Isolated PBMCs from diabetic dyslipidemic subjects indicated enhanced ROS and HOCl generation followed by diabetic subjects without dyslipidemia and healthy controls. We explored increased production of H2O2 and enhanced enzymatic activity of myeloperoxidase (MPO) among diabetic dyslipidemic subjects (p<0.0001) resulting in higher HOCl content., Conclusion: The hyperglycemic and hyperlipidemic challenges together enhance the production of HOCl and the fluoroprobe RHQ may be used as a novel diagnostic marker to evaluate the extent of this toxicity., (Copyright © 2016 Elsevier B.V. All rights reserved.)

On the basis of the Förster resonance energy transfer mechanism between rhodamine and quinoline-benzothiazole conjugated dyad, a new colorimetric as well as fluorescence ratiometric probe was synthesized for the selective detection of Cd(2+). The complex formation of the probe with Cd(2+) was confirmed through Cd(2+)-bound single-crystal structure. Capability of the probe as imaging agent to detect the cellular uptake of Cd(2+) was demonstrated here using living RAW cells.

A new quinoline based sensor was developed and applied for the selective detection of Cd(2+) both in vitro and in vivo. The designed probe displays a straightforward approach for the selective detection of Cd(2+) with a prominent fluorescence enhancement along with a large red shift (∼38 nm), which may be because of the CHEF (chelation-enhanced fluorescence) and ICT (internal charge transfer) processes after interaction with Cd(2+). The interference from other biologically important competing metal ions, particularly Zn(2+), has not been observed. The visible-light excitability of the probe merits in the viewpoint of its biological application. The probe enables the detection of intracellular Cd(2+) with non-cytotoxic effects, which was demonstrated with the live RAW cells. The experimentally observed change in the structure and electronic properties of the sensor after the addition of Cd(2+) were modelled by the density functional theory (DFT) and time-dependent density functional theory (TDDFT) computational calculations, respectively. Moreover, the test strip experiment with this sensor exhibits both absorption and fluorescence color changes when exposed to Cd(2+) in a mixed aqueous solution, which also makes the probe more useful. The minimum limit of detection of Cd(2+) by the probe was in the range of 9.9 × 10(-8) M level.

A new visible-light-excitable fluorescence ratiometric probe for OCl(-) has been developed based on a triphenylamine-diamiomaleonitrile (TAM) moiety. The structure of the dye was confirmed by single-crystal X-ray analysis. It behaves as a highly selective and sensitive probe for OCl(-) over other analytes with a fast response time (∼100 s). OCl(-) reacts with the probe leading to the formation of the corresponding aldehyde in a mixed-aqueous system. The detection limit of the probe is in the 10(-8) M range. The probe (TAM) also exhibits solvatofluorochromism. Changing the solvent from non-polar to polar, the emission band of TAM largely red-shifted. Moreover, the probe shows an excellent performance in real-life application in detecting OCl(-) in human blood cells. The experimentally observed changes in the structure and electronic properties of the probe after reaction with OCl(-) were studied by DFT and TDDFT computational calculations., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A new spirobenzopyran derivative (SPNH) was designed and synthesized which was applied in simultaneous colorimetric and NIR fluorescence detections for Cr(3+). This spirobenzopyran receptor is normally colorless in aqueous organic media but the formation of merocyanine occurs by Cr(3+) showing a yellow color. Here the formation of yellow color in UV-vis spectra and strong NIR fluorescence emission at 675 nm makes SPNH a good sensor for Cr(3+) ion. It is also found to be useful in cell imaging and in construction of logic gate. It shows INHIBIT gate in fluorescence and OR gate in absorption. To the best of our knowledge, this is the first report of NIR fluorescence emission of a spirobenzopyran derivative by Cr(3+) and its application to cell-biology and also in the logic gate.

A spirobenzopyran-quinoline (SBPQ) based sensor was synthesized which selectively detects trivalent ions viz. Al(3+), Fe(3+) and Cr(3+) through a fluorescence turn on signal in the red region (~675 nm) with the detection limit in the order of 10(-8) M. The potentiality of the probe was confirmed by employing it for fluorescence bio-imaging with Al(3+) in three different types of live-cells.

A new fluorescent probe was synthesized from rhodamine-6G and 6-(hydroxymethyl) picolinohydrazide for the sensing of Fe(3+) in an aqueous environment. The structure of the sensor was confirmed through its single crystal X-ray study. It exhibits a high specificity and sensitivity towards Fe(3+) over other interfering heavy and transition metal ions (HTM). The turn-on greenish-yellow fluorescence and a colorimetric change from colourless to pink were observed upon addition of Fe(3+) which evokes almost 116- and 23-fold enhancement in absorbance and emission intensity respectively in an acetonitrile-water (1:1, v/v, 25 °C) solution at a neutral pH (pH = 7.2). The Fe(3+) promoted ring opening of the spirolactam framework to the open chain amide platform of the sensor is responsible for its visible colour change and turn-on fluorescence activity. It also exhibits an excellent performance in the "dip stick" method. Moreover the limit of detection of the probe is in the 10(-8) M range.

A probe based on 2-(2'-hydroxyphenyl) benzothiazole (HBT) has been synthesized and used for the ratiometric detection of hydrazine. The probe is designed in such a way that the excited state intramolecular proton transfer (ESIPT) of the HBT moiety gets blocked. The chemodosimetric approach of hydrazine to the probe results in the recovery of the ESIPT by removal of a free HBT moiety through subsequent substitution, cyclization, and elimination processes. The probe is successfully demonstrated to enable the detection of hydrazine in live cells.

A new "naked-eye" and ratiometric fluorescent zinc sensor (TAQ) of carboxamidoquinoline with 2-chloro-N-(quinol-8-yl)-acetamide as a receptor was designed and synthesized. The sensor shows good water solubility and high selectivity for sensing; about a 15-fold increase in fluorescence quantum yield and a 100 nm red-shift of fluorescence emission upon binding Zn²⁺ in aqueous HEPES buffer solution are observed. The human lung cancer cell line (A549) activity is also demonstrated.

In this study, we have synthesized a simple Schiff base type isophthaloyl salicylaldehyde hydrazone (ISH) moiety which selectively detects Al(III) and PPi with a fluorescence enhancement at two different wavelengths in aqueous solution. The sensing phenomenon is also reversible and thus the sensor beautifully mimics logic gates (INHIBIT and EXOR gates).

For ratiometric "naked eye" detection of CN(-), an ESIPT exhibiting benzothiazole receptor (BHI) is designed having one aldehyde group ortho and the other aldehyde para to the OH group respectively. Due to RAHBs, the ortho aldehyde group is highly reactive undergoing nucleophilic cyanide addition selectively, which hampered ESIPT. This is also supported by DFT and TD-DFT calculations.

A new rhodamine-quinoline based dyad has been synthesized. It shows a highly selective response to Cd(2+) in the presence of other competing metal ions in aqueous media (pH = 7.1). The detection limit of the sensor is in the 10(-7) M level.

In the title compound, C13H12O5, the mean plane of the 2H-chromene ring system (r.m.s deviation = 0.026 Å) forms a dihedral angle of 81.71 (6)° with the mean plane of ethyl 2-hy-droxy-acetate moiety (r.m.s deviation = 0.034 Å). In the crystal, C-H⋯O hydrogen bonds result in the formation of zigzag layers parallel to the bc plane.

In the title compound, C14H17N3O2, the mean plane of the 1,8-naphthyridine ring system (r.m.s deviation = 0.020 Å) forms a dihedral angle of 23.4 (1)° with the acetamide moiety (r.m.s deviation = 0.001 Å). The mol-ecular structure is stabilized by an intra-molecular O-H⋯N hydrogen bond, which generates an S(5) ring motif. In the crystal, mol-ecules are linked into inversion dimers by pairs of N-H⋯O hydrogen bonds, generating 18-membered R 2 (2)(18) ring motifs.