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Highlights: [•] DHA and 9-OH DHA both induce the heme group of BHb. [•] DHA and 9-OH DHA both can change the polarity of BHb. [•] DHA and 9-OH DHA both make BHb unfolding. [•] The interaction between BHb and DHA is stronger than 9-OH DHA. [Copyright &y& Elsevier]

Highlights: [•] A novel water-soluble zinc phthalocyanine was synthesized. [•] The phthalocyanine has strong affinity to CT-DNA. [•] The phthalocyanine can effectively cleavage CT-DNA by irradiation. [•] The phthalocyanine has potential to be used for PDT. [Copyright &y& Elsevier]

Abstract: The interactions between Lysozyme and Hypocrellin A are investigated in details using time-resolved fluorescence, fourier transform infrared spectroscopy (FTIR), circular dichroism spectroscopy (CD), three-dimensional fluorescence spectra, and thermal gravimetric analysis (TGA) techniques. The results of time-resolved fluorescence suggest that the quenching mechanism is static quenching. FTIR and CD spectroscopy provide evidences of the reducing of α-helix after interaction. Hypocrellin A could change the micro-environmental of Lysozyme according to hydrophobic interaction between the aromatic ring and the hydrophobic amino acid residues, and the altered polypeptide backbone structures induce the reduction of α-helical structures. Moreover, TGA study further demonstrates the structure changes of Lysozyme on the effect of Hypocrellin A. This study could provide some important information for the derivatives of HA in pharmacy, pharmacology and biochemistry. [Copyright &y& Elsevier]

Abstract: In this article, the interaction mechanism of prodigiosin (PG) with bovine hemoglobin (BHb) is studied in detail using various spectroscopic technologies. UV–vis absorption and fluorescence spectra demonstrate the interaction process. The Stern–Volmer plot and the time-resolved fluorescence study suggest the quenching mechanism of fluorescence of BHb by PG is a static quenching procedure, and the hydrophobic interactions play a major role in binding of PG to BHb. Furthermore, synchronous fluorescence studies, Fourier transform infrared (FTIR) and circular dichroism (CD) spectra reveal that the conformation of BHb is changed after conjugation with PG. [Copyright &y& Elsevier]

Abstract It is found that hypobromous acid (HOBr) can affect the activity of type IV collagen. Herein, we synthesized a lysosome-targeted fluorescence probe NA-lyso based on Suzuki coupling reaction with naphthalimide as a fluorescent group. HOBr can oxidize the amino group and methylthio group, which increased the degree of conjugation of the probe, thereby affecting its optical properties. Accordingly, it can establish a method for the specific detection of HOBr. NA-lyso has the properties including fast response, high fluorescence quantum yield (Φ = 59.17%), high selectivity, low cytotoxicity and good membrane-permeability. The probe can locate to lysosome of cells. The potential of the probe as biosensor for HOBr was demonstrated by imaging of exogenous and endogenous HOBr in living cells and in mice. In consequence, NA-lyso is expected to be a powerful tool to detect HOBr in complex biosystem and provides a means of exploring physiological functions associated with HOBr in living organisms. Graphical Abstract Unlabelled Image Highlights • A lysosome-targeted fluorescence probe NA-lyso for monitoring HOBr was synthesized. • The probe can respond to HOBr with outstanding sensitivity and selectivity. • The probe can target in lysosome and monitoring the level of HOBr in Hela cells. • The probe can also be used to image HOBr in vivo. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two novel A-A type dithienylethene derivatives have been developed. • They showed an efficient solvent-dependent photochromism. • Excellent photoswitching behavior was observed in the PMMA film state. • The DFT calculations further confirmed the above experimental results. Exploring novel dithienylethenes (DTEs) with efficient photochromism has drawn increasing attention in virtue of the potential applications for photoelectric functional materials. In this contribution, we presented two novel acceptor–acceptor (A-A) type DTE derivatives (4a and 4b) by incorporating the diestervinyl moieties with strong electron-withdrawing capacity into two sides of DTE skeleton. The corresponding structures were well confirmed by the NMR (1H and 13C) and HRMS. When irradiated alternately with ultraviolet and visible light, 4a and 4b showed efficient photochromism in toluene, chloroform and DMSO, clearly implying a solvent-dependence feature. Moreover, excellent photoswitching behaviors were also observed in the poly(methyl methacrylate) (PMMA) film. The density functional theory (DFT) calculations suggested that strong Acceptor-Acceptor effect plays a dominative role in the efficient photochromic performance. Hence, this study will provide a useful guidance for developing high-performance DTE derivatives in multi-media. [ABSTRACT FROM AUTHOR]

β-tetra (aminophenoxy) sulfonic substituted zinc phthalocyanines (SNZnPc), a novel amphiphilic zinc phthalocyanine (Pc), was synthesized. The photophysical, photochemical, and photobiology properties were studied. Results indicated that the synthesized SNZnPc has good amphiphilic property and high reactive oxygen species (ROSs) generation ability. Furthermore, SNZnPc has strong affinity to calf thymus DNA (CT-DNA) through intercalation ways and can effectively cleavage CT-DNA after irradiation by light with appropriate wavelength. [ABSTRACT FROM AUTHOR]

The interaction of UCPs with CT DNA are studied in detail by zeta potential, Energy dispersive spectrometer (EDS) spectroscopy, Thermogravimetric (TGA) analysis, DNA melting determination and various spectroscopic techniques including Ultraviolet–Visible (UV–Vis) absorption, fluorescence, circular dichroism (CD), Fourier transform infrared (FTIR) and Raman spectroscopy. The results indicate that CT DNA can assemble on the surface of UCPs mainly by relative stronger hydrophobic force and electrostatic binding, and the predominant interaction site is the deoxyribosyl phosphate backbone of CT DNA. Moreover, after interacting with UCPs, the double helix structure of DNA is undamaged. [ABSTRACT FROM AUTHOR]

Highlights: [•] PG intercalated into the DNA helix. [•] The binding of PG and ct-DNA are partial intercalation mode. [•] Van der Waals forces are mainly between PG and ct-DNA in the present of EB. [•] The interaction follows the static quenching mechanism. [Copyright &y& Elsevier]

Highlights: [•] Ga3+–HA can bind to Mb to form a stable complex. [•] The interaction follows the static quenching mechanism. [•] The microenvironment and conformation for Mb is changed in the presence of Ga3+–HA. [ABSTRACT FROM AUTHOR]

Abstract: The spectrophotometric and spectrofluorimetric studies revealed that hemoglobin (Hb) could interact with hypocrellin A, a photosensitizing drug used in photodynamic therapy. It was found that this kind of interaction can induce the conformational changes in Hb. In addition, based on fluorescence quenching titration and electron paramagnetic resonance spectroscopy results, the binding parameters, thermodynamic parameters are obtained. The quenching mechanism is also proposed. [Copyright &y& Elsevier]

Abstract: A porphyrin meso-tetrakis{[4-(1-pyridyl)propoxy]phenyl}porphyrin (TPyPP) and its Ni complex (TPyPP(Ni)) have been synthesized and characterized by 1H NMR, UV–vis spectra. The interaction of two porphyrins with calf thymus-DNA (CT-DNA) has been explored by UV–vis, fluorescence and circular dichroic spectroscopy and viscosity measurements. The results suggest that these porphyrins can bind to DNA by the same binding mode. TPyPP outside binds by self-stack with DNA both at low drug load r (=[porphyrin]/[DNA]) and high drug load. Though TPyPP(Ni) has center metal nickel, binding mode with DNA has little difference compared with TPyPP, dominating out-binding mode with different direction along DNA. The binding constants of the TPyPP and TPyPP(Ni) to DNA were 4.65 × 105 M−1 and 3.2 × 105 M−1, respectively. A colored precipitate was found after time in two porphyrin''s viscosity measurement. The reasonable interpretation is the porphyrins with alkyl connected N-position of pyridine can strongly interact with the anionic phosphates of DNA and lead to hydrophobic complex. [Copyright &y& Elsevier]

Barbituric acid derivatives with typical aggregation induced emission (AIE) are reported. Their emission wavelengths varied with water fraction of their solution. UV–visible absorption spectroscopy and theoretical calculations revealed the intramolecular charge transfer (ICT) possibility from donor to acceptor and the mechanism was confirmed as a restriction of intramolecular motion (RIM). The AIE properties were affected by the different substituents on barbituric acid. When the molecular volume increased, the AIE effect decreased. Fluorescent quenching mechanism was applied to detect nitroaromatic explosives. For 2,4,6-trinitrophenol (PA), one of the derivatives 5-(4-diphenylamino styrene)-1,3-diphenyl-barbituric acid in THF/H 2 O mixture (1:9, v/v), showed amplified fluorescence quenching with a maximum Stern–Volmer quenching constant of 4.1 × 104 M−1. The solid phase paper test based on 5-(4-diphenylamino styrene)-1,3-diphenyl-barbituric acid also showed a superior sensitivity toward PA both in vapor and solution. Unlabelled Image • We founded that the AIE properties were affected by the different substituents on barbituric acid. • The presence of isomers reduces the fluorescence stability of the compound in the aggregated state. • The compounds can be used for the detection of nitroaromatics in aqueous media. [ABSTRACT FROM AUTHOR]