Applicability of Reddish-Orange Light Emitting Samarium (III) Complexes for Biomedical and Multifunctional Optoelectronic Devices.

Six crimson samarium (III) complexes based on ß-ketone carboxylic acid and ancillary ligands were synthesized by adopting the grinding technique. All synthesized complexes were investigated via elemental analysis, infrared, UV-Vis, NMR, TG/DTG and photoluminescence studies. Optical properties of these photostimulated samarium (III) complexes exhibit reddish-orange luminescence due to 4G5/2 → 6H7/2 electronic transition at 606 nm of samarium (III) ions. Further, energy bandgap, color purity, CIE color coordinates, CCT and quantum yield of all complexes were determined accurately. Replacement of water molecules by ancillary ligands enriched these complexes (S2-S6) with decay time, quantum yield, luminescence, energy bandgap and biological properties than parent complex (S1). Interestingly, these efficient properties of complexes may find their applications in optoelectronics and lighting systems. In addition to these, the antioxidant and antimicrobial assays were also investigated to explore the applications in biological assays.

Differential thermal analysis reveals the sensitivity of sweet cherry flower organs to low temperatures.

The frequency and severity of spring frosts increase during the budburst in many regions of the world as global warming increases. Variability in the freezing resistance of sweet cherry flower organs during the active growing period has been rarely documented, especially in regard to the sepal, pedicel, receptacle, petal, stamen, and pistil organs of flower at the deacclimation stage. The freezing resistance of flower organs of six sweet cherry cultivars was investigated at regular intervals from the first white stage through the full bloom stage using differential thermal analysis (DTA) for 2019-2020. For most of the cultivars, petal and stamen organs of flower exhibited higher freezing resistance than other flower organs. There were significant differences in frost tolerance among cultivars, and 'Van' and 'Wild Genotype' had a lower level of low temperature exotherms or critical temperatures (LT50 values) in both stages, whereas 'Merton Late' was more sensitive to frost than other cultivars. Additionally, an increase in LT50 values in all cultivars was observed with the progression of the budburst. The results in the present study can increase the certainty of decision-making regarding the timing and methods to increase the air temperature in orchards during spring frost events to prevent frost damage. Larger data sets are required to further validate our results, and future efforts should thus be focused on determining the critical temperatures of flower organs using different measurement techniques.

The use of differential thermal analysis in determining the critical temperatures of sweet cherry (Prunus avium L.) flower buds at different stages of bud burst.

Many studies to date on the response of cherry flower buds to frost have focused on visual evaluations by observing tissue browning after frost event in the orchard and laboratory conditions but only little knowledge is available on the consequences of intracellular ice formation on cellular ultrastructure that underlies exothermic reactions during bud burst stages. In this study, the differential thermal analysis (DTA) method was used to investigate critical frost temperatures for the sweet cherry cultivars '0900-Ziraat', 'Erzincan Macar', 'Lambert', 'Vista', 'Stella', and 'Early Burlat' under laboratory-based freeze assays. In the course of our experimental study, frost tolerance or cell death points (CDPs) of flowers of six cherry cultivars were investigated in consecutive phenological stages from the start to the end of blooming, for 2 years. The frost tolerance of flower buds changed according to different developmental stages and cherry cultivars. Our results of frost tolerance tests performed on the cherry blooming stages are rather controversial. Our findings have shown that at the open cluster stage, the frost tolerance of the flower buds is very sensitive (mCDP = -1.18°C for 'Lambert'), while the first white stage has revealed an important increase (mCDP= -9.96°C for '0900-Ziraat') in the frost tolerance of those. Averaged over 2 years, the temperatures causing 50% frost damage for flower buds were -2.08 to -3.76°C at the side green stage, -1.49 to -3.22°C at the green tip stage, -1.18 to -1.98°C at the open cluster stage, -7.92 to -9.96°C at the first white stage, and -6.29 to -9.36°C at the full bloom stage in the range of six cultivars. Based on our test results, '0900-Ziraat' and 'Vista' were regularly classified as frost-tolerant cultivars. The flower buds of 'Lambert' and 'Early Burlat' have been regularly the most sensitive, while 'Erzincan Macar' and 'Stella' were ranked into the group of medium sensitivity. These results can help farmers to estimate possible frost damages on sweet cherry flower buds due to frost events at the investigated phenological stages.

Determining the release kinetics of risperidone controlled release matrices to treat schizophrenia.

Risperidone is an atypical antipsychotic agent clinically used to treat schizophrenia, bipolar diseases, and autism. Usually, the frequency of doses is twice daily. In the present study, risperidone controlled release matrices formulated using hydrophilic and hydrophobic polymers. The tablets were prepared by direct compression. The pre-compression and post-compression properties were assessed, along with swelling studies. The morphology of particles observed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The stability study on the drug was performed using thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). The optimized formulation was prepared with the help of hydrophilic polymer K100M (40% ratio). Furthermore, release kinetics had investigated. The release pattern of optimized formulation FT5 fitted best to zero-order kinetics and showed excellent release characteristics. The model-independent approach had been used, formulations FT6 and FT8 showed resemblance with FT5 in all three media, respectively. The once daily formulation of risperidone could be beneficial for schizophrenia patients and their caregivers and will improve patient compliance.

Preparation and tribological behaviour of poly(methyl methacrylate) (PMMA) microcapsules containing friction modifiers.

Aims: Microcapsules comprising of a poly(methyl methacrylate) (PMMA) shell and friction modifier (FM) core were prepared to reduce the friction and extend the service life of engine lubricating oil.Methods: Microcapsules containing both organic FM and molybdenum FM were produced via solvent evaporation technique. The friction coefficient, thermal stability, and chemical composition of microcapsules were investigated.Results: The incorporation of microcapsules in lubricating oil dramatically reduced the friction coefficient to be lower than that of virgin FM. Organic FM and molybdenum FM are compatible during the encapsulation process. The release of the FM inside the microcapsules was controllable by thermal degradation of polymeric shell at 150 °C or mechanical rupture at room temperature.Conclusions: This study provided a novel approach to improve the tribological properties of lubricating oil with long service life, facile fabrication and low cost and will find potential applications in lubrication industry for internal combustion engines.

Role of Copper Oxide on Epoxy Coatings with New Intumescent Polymer-Based Fire Retardant.

Epoxy resins (EP) have been used as a thermos-setting material in the field of coating, casting, bonding agent, and laminating. However, a major drawback associated with its use is the lack of good flaming properties, and it is responsible for heavy smoke along with hazardous gases considerably limiting its uses in various fields. In this study, N-ethanolamine triazine-piperizine, a melamine polymer (ETPMP), was established as a new charring-foaming agent and was successfully synthesized with ethanolamine, piperizine, cyanuric chloride, and melamine as precursor molecules via the nucleophilic substitution reaction method. Elemental analysis and Fourier transform infrared (FTIR) spectroscopy analysis were applied to approve the synthesis of ETPMP and confirmation of its structure and characterization. The epoxy coating of intumescent flame retardant (IFR) was equipped by introducing ETPMP, ammonium polyphosphate (APP), and copper oxide (CuO) in multiple composition ratios. CuO was loaded at various amounts into the IFR-coating system as a synergistic agent. The synergistic action of CuO on IFR coatings was scientifically examined by using different analytical tests such as vertical burning test (UL-94V), limited oxygen index (LOI), thermal gravimetric analysis (TGA), cone calorimeter, and scanning electron microscope (SEM). The results showed that small changes in the amount of CuO expressively amplified the LOI results and enhanced the V-0 ratings in the UL-94V test. The TGA data clearly demonstrate that the inclusion of CuO can transform the thermal deprivation behavior of coatings with a growing char slag proportion with elevated temperatures. Information from cone calorimeter data affirmed that CuO can decrease the burning factors by total heat release (THR) together with peak heat release rate (PHRR). The SEM images indicated that CuO can enrich the power and compression of the intumescent char that restricts the movement of heat and oxygen. Our results demonstrate a positive influence of CuO on the epoxy-headed intumescent flame retardant coatings.

Synthetic Analogues of Aminoadamantane as Influenza Viral Inhibitors-In Vitro, In Silico and QSAR Studies.

A series of nineteen amino acid analogues of amantadine (Amt) and rimantadine (Rim) were synthesized and their antiviral activity was evaluated against influenza virus A (H3N2). Among these analogues, the conjugation of rimantadine with glycine illustrated high antiviral activity combined with low cytotoxicity. Moreover, this compound presented a profoundly high stability after in vitro incubation in human plasma for 24 h. Its thermal stability was established using differential and gravimetric thermal analysis. The crystal structure of glycyl-rimantadine revealed that it crystallizes in the orthorhombic Pbca space group. The structure-activity relationship for this class of compounds was established, with CoMFA (Comparative Molecular Field Analysis) 3D-Quantitative Structure Activity Relationships (3D-QSAR) studies predicting the activities of synthetic molecules. In addition, molecular docking studies were conducted, revealing the structural requirements for the activity of the synthetic molecules.

Understanding Concomitant Physical and Chemical Transformations of Simvastatin During Dry Ball Milling.

The present study investigates concomitant processes of solid-state disordering and oxidation of simvastatin during milling. The separate dry ball milling of crystalline and amorphous powders of simvastatin were conducted at ambient temperature for 10 and 60 min each. The relative crystallinity was determined using X-ray scattering and oxidative degradation was analyzed using liquid chromatography. The physical and chemical transformations in the milled powder were evaluated using modulated differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy. The disordering during milling of the crystalline powder was found to progressively decrease the crystallinity. For the amorphous starting material, milling for 10 min induced a large extent of recrystallization, while milling for 60 min largely re-amorphized the powder. This solid-state disordering and/or ordering were accompanied by progressive air oxidation during milling. The infrared spectroscopic analysis revealed the molecular manifestations associated with the physicochemical transformations in the disordered solid states. The melting point of simvastatin depressed systematically with the increase in the degree of disorder as well as the degradation. The in situ cooling in DSC of milled samples from their molten state led to the formation of the co-amorphous phase between the drug and degradation products, which showed a consistent increase in glass transition temperature with the increase in the content of degradation products. The study overall demonstrates the solid-state re-ordering and disordering of crystalline and amorphous simvastatin accompanied by chemical degradation as the consequence of the mechano-activation.

Thermal analysis of marginal conditions to facilitate cryopreservation by vitrification using a semi-empirical approach.

This study aims at the thermal analysis of marginal conditions leading to cryopreservation by vitrification, which appears to be the only alternative for indefinite preservation of large-size tissues and organs. The term "marginal conditions" here refers to cooling rates in close range with the so-called critical cooling rate, above which crystallization is avoided. The analysis of thermal effects associated with partial crystallization during vitrification is associated with the coupled phenomena of heat transfer and kinetics of crystallization. This study takes a practical, semi-empirical approach, where heat transfer is analyzed based on its underlying theoretical principles, while the thermal effects associated with partial crystallization are taken into account by means of empirical correlations. This study presents a computation framework to solve the coupled problem, while presenting a proof-of-concept for DP6 as a representative cryoprotective agent. The thermal effects associated with crystallization at various relevant cooling rates are measured in this study by means of differential scanning calorimetry. Results of this study demonstrate that, due to the thermal effects associated with partial crystallization, the cooling rate at the center of a large organ may lag behind the cooling rate in its surroundings under some scenarios, but may also exceed the surroundings cooling rate in other scenarios, leading to counter-intuitive effects associated with partial crystallization.

Characterization of bound water in skin hydrators prepared with and without a 3D3P interpenetrating polymer network.

BACKGROUND: Hyaluronic acid (HA) has been considered the gold standard ingredient for improving skin hydration and combating age-related effects, however it is an inefficient polymer with inconsistent results partially due to its poor skin penetration, surface deposition, and rapid degradation. Herein we report the synthesis and in vitro characterization of a newly developed, topical super-humectant with the goal of attracting and binding water molecules more efficiently than traditional, cosmetic-grade forms of HA. METHODS: A modified interpenetrating polymer network (IPN) was developed using three polymers into a three-dimensional formation (3D3P) for entrapping HA and water. This 3D3P-IPN functions as a super-humectant, attracting and binding water molecules more efficiently than the traditional cosmetic-grade forms of HA. We compare 3D3P-IPN serum samples to a traditional commercial benchmark product of similar ingredients using microscopic analysis, rheology, Karl Fischer (KF) titration, differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and dynamic vapor sorption (DVS) techniques. RESULTS: The 3D3P-IPN samples appeared to bind water tighter than the benchmark sample as evidenced by maximum endpoints of endotherms occurring at significantly higher temperatures. The DVS results further confirm this speculation as the 3D3P-IPN samples lost approximately 10% less water up to 35% RH than the benchmark. The 3D3P-IPN samples also absorbed more water as the humidity level increased,demonstrating superior humectant properties. KF titration indicated that all three samples had similar water concentrations; however, TGA results demonstrated that the benchmark (a viscous, humectant-rich hydrating masque) did not have much bound water. CONCLUSION: Through the synthesis of a 3D3P-IPN using simplified methods, we were able to increase the water-binding and HA-delivery capabilities of a thin serum. This 3D3P-IPN serum has potential to deliver more hydration to the skin's surface compared to traditional HA formulations.

The Main (Glyco) Phospholipid (MPL) of Thermoplasma acidophilum.

The main phospholipid (MPL) of Thermoplasma acidophilum DSM 1728 was isolated, purified and physico-chemically characterized by differential scanning calorimetry (DSC)/differential thermal analysis (DTA) for its thermotropic behavior, alone and in mixtures with other lipids, cholesterol, hydrophobic peptides and pore-forming ionophores. Model membranes from MPL were investigated; black lipid membrane, Langmuir-Blodgett monolayer, and liposomes. Laboratory results were compared to computer simulation. MPL forms stable and resistant liposomes with highly proton-impermeable membrane and mixes at certain degree with common bilayer-forming lipids. Monomeric bacteriorhodopsin and ATP synthase from Micrococcus luteus were co-reconstituted and light-driven ATP synthesis measured. This review reports about almost four decades of research on Thermoplasma membrane and its MPL as well as transfer of this research to Thermoplasma species recently isolated from Indonesian volcanoes.

Novel Thermal Imaging Method for Rapid Screening of Drug-Polymer Miscibility for Solid Dispersion Based Formulation Development.

This study aimed to develop a rapid, simple, and inexpensive screening method for selecting the best polymeric candidates possessing high active pharmaceutical ingredient (API) miscibility during the early stages of formulation development of solid dispersion based pharmaceutical products. A new thermal imaging based method, thermal analysis by structural characterization (TASC), was used as a thermoptometric tool in conjunction with data analysis software to detect the melting point depression and postmelting dissolution of felodipine particles screened over thin spin-coated films of ten polymers commonly used in the pharmaceutical field. On the polymeric substrates the drug showed different degrees of melting point reduction, reflecting their different levels of polymer-drug miscibility. Using TASC to detect melting point depression is significantly (20-40 times) faster than the conventional DSC method without loss of the sensitivity of detection. The quantity of the material required for the screening is less than 1/1000th of the material used in conventional DSC tests, which significantly reduce the material wastage. Isothermal TASC tests and IR imaging confirmed the occurrence of thermal dissolution of the drug in the polymer for more miscible pairs. The real-time stability tests validate the accuracy of the polymer-drug miscibility screening results. These results demonstrate TASC as a promising screening tool for rapidly selecting the polymeric excipients for pharmaceutical formulations development.

Thermal liquid biopsy for monitoring melanoma patients under surveillance during treatment: A pilot study.

BACKGROUND: Differential Scanning Calorimetry (DSC) is a technique traditionally used to study thermally induced macromolecular transitions, and it has recently been proposed as a novel approach for diagnosis and monitoring of several diseases. We report a pilot study applying Thermal Liquid Biopsy (TLB, DSC thermograms of plasma samples) as a new clinical approach for diagnostic assessment of melanoma patients. METHODS: Multiparametric analysis of DSC thermograms of patient plasma samples collected during treatment and surveillance (63 samples from 10 patients) were compared with clinical and diagnostic imaging assessment to determine the utility of thermograms for diagnostic assessment in melanoma. Nine of the ten patients were stage 2 or 3 melanoma subjects receiving adjuvant therapy after surgical resection of their melanomas. The other patient had unresectable stage 4 melanoma and was treated with immunotherapy. Two reference groups were used: (A) 36 healthy subjects and (B) 13 samples from 8 melanoma patients who had completed successful surgical management of their disease and were determined by continued clinical assessment to have no evidence of disease. RESULTS: Plasma thermogram analysis applied to melanoma patients generally agrees with clinical evaluation determined by physical assessment or diagnostic imaging (~80% agreement). No false negatives were obtained from DSC thermograms. Importantly, this methodology was able to detect changes in disease status before it was identified clinically. CONCLUSIONS: Thermal Liquid Biopsy could be used in combination with current clinical assessment for the earlier detection of melanoma recurrence and metastasis. GENERAL SIGNIFICANCE: TLB offers advantages over current diagnostic techniques (PET/CT imaging), limited in frequency by radiation burden and expense, in providing a minimally-invasive, low-risk, low-cost clinical test for more frequent personalized patient monitoring to assess recurrence and facilitate clinical decision-making.

Properties of a novel carboxymethyl chitosan derived from silkworm pupa.

In this study, a carboxymethyl chitosan derived from silkworm pupa (SP-carboxymethyl chitosan) was prepared. The physical characteristics of the SP chitin, chitosan, and carboxymethyl chitosan were analyzed. The scanning electron microscopy results showed that the surfaces of the samples from SP were more uneven, with more surface fractures compared with those of the reference substance (RS). Thermal analysis, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy analysis showed that the main molecular chain structures of SP samples and RSs had no substantial differences. However, the crystallinity and thermal decomposition temperature of the SP samples were lower compared with those of the RSs. All of these results provide a theoretical basis for the development of applications for the SP-carboxymethyl chitosan.

Multicomponent crystals of gliclazide and tromethamine: preparation, physico-chemical, and pharmaceutical characterization.

OBJECTIVE: To improve the pharmaceutical behavior of the oral antidiabetic agent gliclazide through the synthesis of multicomponent crystals with tromethamine. METHODS: Multicomponent crystals were prepared by solvent evaporation method, kneading, and combining mechanical and thermal activation. DSC, FT-IR spectroscopy, X-ray diffraction, SEM-EDS, and SSNMR were used to investigate their formation. Measurements of solubility and dissolution rate were carried out for the pharmaceutical characterization. RESULTS: The formation of multicomponent crystals of gliclazide and tromethamine was confirmed by all the techniques. In particular, FT-IR and NMR measurements revealed that the interaction between drug and coformer leads to significant changes of the hydrogen bond scheme, and that almost all the functional groups of the two molecules are involved. The dissolution profile of the new phase is significantly better than that of both pure gliclazide and of the reference commercial product Diabrezide®. CONCLUSIONS: The new system shows an improved pharmaceutical behavior and could be formulated in a dosage form to obtain a rapid and complete release of the drug available for absorption.

Hydro-alcoholic media effects on theophylline release from sesamum polysaccharide gum matrices.

Concomitant ingestion of alcohol and medications can greatly affect drug plasma concentrations as dose dumping or failure may occur as a result of the fact that formulation excipients may not always be resistant to alcohol. In this study, a natural polysaccharide (Sesamum radiatum gum) (SG) was extracted, characterized and used to formulate sustained release theophylline compacts to study the effect of varying alcohol concentrations (v/v) in dissolution media on drug release from these compacts. X-ray powder diffraction showed that the extracted gum was amorphous in nature with the powder having excellent compaction properties as observed with its compact being significantly harder than those prepared with pure hydroxypropyl methyl cellulose (HPMC) K4M. X-ray microtomography showed that the compacts produced were homogenous in nature, however, swelling studies showed failure of the compacts at the highest concentration of absolute ethanol used (40% v/v). Dissolution studies showed similarity at all levels of alcohol tested (f2 = 57-91) in simulated gastric (0.1 N HCl, pH 1.2) and intestinal fluids (phosphate buffer, pH 6.8) for the HPMC compacts whereas dissimilarity only occurred for the SG compacts at the highest alcohol concentration in both media (f2 = 35). The suitability of SG as a matrix former that can resist alcoholic effects therefore makes it suitable as an alternative polymer with wider applications for drug delivery.

Synthesis, characterization and antimicrobial study of polymeric transition metal complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II).

Salen ligands comprising of o-phenylenediamine (salop) and p-phenylenediamine (salpp) have been synthesized. The salen ligand, salop undergo Schiff base reaction with Formaldehyde and Barbituric acid to generate novel polymeric Schiff base, SBOPA in one instance while the second salen ligand, salpp on Schiff base reaction with formaldehyde and piperazine gives another novel polymeric Schiff base, SBPBA. These polymeric Schiff base ligands, SBOPA and SBPBA generates polymeric metal complexes in high yields on reaction with transition metal acetates, M(CH3COO)2.xH2O where M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The polymeric Schiff bases, SBOPA and SBPBA and their transition metal complexes were systematically characterized, using various spectroscopic techniques. The structure, composition and geometry of SBOPA and SBPBA and their metal complexes were confirmed by spectral techniques (FT-IR, and 1H NMR), elemental analysis, and electronic spectra magnetic moment. On the basis of FT-IR, 1HNMR, electronic spectra and magnetic moment values Mn(II), Co(II) and Ni(II) ion were found to have octahedral geometry while Cu(II) and Zn(II) were found to be square-planar in nature. Thermogravimetric analysis (TGA) was used to evaluate their thermal behaviour and Cu(II)-SBOPA and Cu(II)-SBPBA were found to be thermally most stable. The polymeric Schiff base ligands, SBOPA and SBPBA and their metal complexes have also been screened for their plausible antimicrobial activity. Tetracyclin and Miconazole were used as standard drug to study the antibacterial and antifungal activity respectively. The Cu(II)-SBOPA and Cu(II)-SBPBA were found to be most potent antimicrobial agents.

Structural and thermal analyses of zinc and lactose in homeopathic triturated systems.

BACKGROUND: A series of different experimental approaches was applied in Zincum metallicum (Zinc met.) samples and lactose controls. Experiments were designed to elucidate the effect of zinc trituration and dynamization on physicochemical properties of homeopathic formulations, using lactose as excipient. METHODS: Zinc met. potencies (Zinc met 1-3c) were triturated and dynamized using lactose as excipient, according to Brazilian Homeopathic Pharmacopoeia. Lactose samples (LAC 1-3c) were also prepared following the same protocol and used as controls. The samples were analyzed structurally by Atomic Absorption Spectroscopy (AAS), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) with Energy Dispersive X-ray Spectroscopy (EDX) and Scanning Electron Microscopy (SEM), and thermodynamically by Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC). RESULTS: AAS analysis detected 97.0 % of zinc in the raw material, 0.75 % (Zinc met 1c) and 0.02% (Zinc met 2c). XRD analysis showed that inter-atomic crystalline spacing of lactose was not modified by dynamization. Amorphous and crystalline lactose spheres and particles, respectively, were observed by TEM in all samples, with mean size from 200 to 800 nm. EDX obtained with TEM identified zinc presence throughout the amorphous matter but individualized zinc particles were not observed. SEM images obtained from dynamized samples (LAC 1c and Zinc met 1c) with electron backscattering could not identify zinc metal grains. The dynamization process induced Derivatives of Thermal Gravimetric (DTg) peak modification, which was previously centered near 158°C to lactose, to a range from 140 to 170°C, suggesting the dynamization process modifies the temperature range of water aggregation. Thermal phenomena were analyzed and visualized by Analysis of Variance (ANOVA) and Principal Component Analysis (PCA) statistics. Both indicated that fusion enthalpy of dynamized samples (DynLAC 1-3c; DynZn 1-3c) increased 30.68 J/g in comparison to non-dynamized lactose (LAC; p < 0.05). CONCLUSIONS: Our results suggested no structural changes due to the trituration and dynamization process. However, TG and DSC analyses permit the differentiation of dynamized and non-dynamized groups, suggesting the dynamization process induced a significant increase in the degradation heat. These results call for further calorimetric studies with other homeopathic dilutions and other methodologies, to better understand the dynamics of these systems.

Aza-Bambusurils En Route to Anion Transporters.

Previous calculations of anion binding with various bambusuril analogs predicted that the replacement of oxygen by nitrogen atoms to produce semiaza-bambus[6]urils would award these new cavitands with multiple anion binding properties. This study validates the hypothesis by efficient synthesis, crystallography, thermogravimetric analysis and calorimetry. These unique host molecules are easily accessible from the corresponding semithio-bambusurils in a one-pot reaction, which converts a single anion receptor into a potential anion channel. Solid-state structures exhibit simultaneous accommodation of three anions, linearly positioned within the cavity along the main symmetry axis. The ability to hold anions at a short distance of about 4 Šis reminiscent of natural chloride channels in E. coli, which exhibit similar distances between their adjacent anion binding sites. The calculated transition-state energy for double-anion movement through the channel suggests that although these host-guest complexes are thermodynamically stable they enjoy high kinetic flexibility to render them efficient anion channels.

A bimodal fluorescent and photocytotoxic naphthalene diimide for theranostic applications.

We report on the potential of a water-soluble tetracationic quaternary ammonium naphthalene diimide (NDI) as multifunctional agent of interest for theranostic applications. The DNA binding ability of this NDI has been investigated. NDI exhibits high binding constants for G-quadruplex DNA but it is not selective for this type of DNA. Taking advantage of its intrinsic fluorescence and singlet oxygen sensitizing ability, cellular uptake, cytotoxicity and photocytotoxicity have been investigated. The intense emission in the red/NIR allows monitoring of the cell permeability of this charged tetracationic NDI, accumulating into the cell nuclei. No dark cytotoxicity has been observed on selected tumor cell lines. Irradiation of the NDI loaded cells with red light reduces cell viability up to 40% and causes a significant increase of the percentage of cells expressing γH2AX foci indicating DNA damage. The presence of distinct DNA damage foci inside the nucleus suggests that the NDI molecule might induce DNA damage in specific sites. To the best of our knowledge this is the first NDI exhibiting PDT activity at µM concentration combined with low dark cytotoxicity.