Influence Of CB Research Articles

Expanding the Color Range of Photoresponsive Multicolor Luminescent System Through Host-Guest Interaction.

Photoresponsive multicolor luminescent systems offer interesting functions, which have led to applications in anticounterfeiting and biological imaging. However, expanding the color range of these materials remains a challenging task. Herein, a carbazole-modified dithienylethene derivative (DTE-CZ) that exhibits modulated fluorescence color changes through the photocyclization reaction and photolysis reaction is synthesized. DTE-CZ emits orange fluorescence, and it can release a fluorophore which emits blue fluorescence by the photolysis reaction, resulting in the color change. Upon complexation of DTE-CZ with cucurbit[10]uril (CB[10]), the fluorescence wavelength will have a blue shift and the photolysis reaction will be inhibited. Benefiting from the influence of CB[10] and the photolysis reaction of free guests, the color range of the photoresponsive system which is composed of free guests and host-guest complexes is further extended. White light emission along with a color shift from yellow-green to blue was achieved by adjusting the ratio of free guests to host-guest complexes. Finally, the photoresponsive multicolor systems are utilized to construct a photostimulated PVA film and an information encryption system. This work provides an alternative strategy for the preparing of photoresponsive multicolor luminescent system and modulation of its color range.

Structure and thermal stability of phosphochlorinated polybutadiene/carbon black composite synthesized via oxidative chlorophosphorylation reaction

The aim of the presented work was to obtain a new type of homogeneous composite based on an industrial polymer (polybutadiene, PB) and a well-known inexpensive filler (carbon black P-234, CB). For this purpose, the reaction of oxidative chlorophosphorylation (OxCh) was used. This makes it possible to introduce CB into the cross-linked structure of the modified polymer and ensure optimal distribution of the filler in it. The structure and thermal stability of the composite synthesized by the OxCh reaction were studied. Analysis of the composite by Fourier-transform infrared spectroscopy indicates a uniform distribution of carbon black in the network structure of the matrix and the physical interaction of the phases of the composite. Ultraviolet-visible spectrum data confirmed the improvement in light absorption in a wide range of the electromagnetic spectrum and the decrease in the optical band gap energy of the phosphochlorinated PB (PhPB) matrix with the addition of CB (Eg of PhPB = 3.25 eV; Eg of PhPB/CB composite = 2.28 eV). The influence of CB on the thermal stability of the PhPB matrix was studied using thermogravimetric and differential thermogravimetric analysis. After thermal analysis, the char yield for PhPB was 41 wt. %, and for PhPB/CB composite was 35.2 wt. %. Compared to PhPB, the increase in char yield, the decrease in maximum thermal decomposition temperature, and the high-integrated thermal decomposition temperature for the PhPB/CB composite show the improvement in the thermal stability of PhPB due to CB.

Evaluation of cell and hemocompatibility of Cucurbiturils

BackgroundCucurbiturils (CB) are pumpkin-shaped macrocyclic molecules consisting of methylen-bridged glycoluril units. Because of their complexing characteristics, they can be used as drug containers for medical purposes. For future biomedical and dermal application of CB, the investigation of cell compatibility is essential. Little is known about the influence of CB on eukaryotic cells, especially on dermal keratinocytes. The structurally related cyclodextrins are known to induce cell death by apoptosis in HaCaT keratinocytes as well as hemolysis in erythrocytes. ObjectiveTo examine cytotoxic effects of different CB. MethodsDifferent cytotoxicity tests were performed on HaCaT keratinocytes and erythrocytes incubated with CB[5], CB[6], and CB[7]. ResultsCB[5] and CB[6] did not lead to cytotoxic reactions at high concentrations up to 30 mg/mL whereas incubation with CB[7] triggered apoptosis at a concentration of 3.75 mg/mL. None of the investigated CB caused hemolytic effects on erythrocytes. ConclusionThese results confirm the high potential of CB as host-complexes for biomedical and dermal applications.

Cucurbit[7]uril: an emerging candidate for pharmaceutical excipients

Cucurbit[7]uril (CB[7]), belonging to the cucurbit[n]uril family (CB[n], n = 5-8, 10, or 13-15), may form host-guest complexes with a variety of small molecules of biomedical interest. The physical and chemical properties of the complexed drugs are often improved as a result of this complexation, suggesting the potential application of CB[7] as a pharmaceutical excipient. This review has summarized the most recent research progress reported between 2011 and early 2017 regarding the biocompatibility of CB[7] and the influence of CB[7] on the stability, solubility, biouptake, and biological activities (including therapeutic efficacies and toxicities) of guest drug molecules. Through this systemic summary and analysis, we intend to stimulate further research efforts in this area and promote the use of CB[7] as an emerging pharmaceutical excipient to improve various properties of drug molecules (or active pharmaceutical ingredients).

Investigating and modelling of light intensity distribution inside algal photobioreactor

Light distribution inside algal culture at different incident light intensities (I0=70–350μmolm−2s−1) and biomass concentrations (Cb=0.09 −1.34gL−1) for various configurations of vessels (rectangular and cylindrical) and illuminations (single and even light directions) are investigated and discussed. At Cb >0.5gL−1 the results showed that the influence of I0 is insignificant, particularly at far distances from the illuminated surface, and increasing I0 is not an efficient solution for facilitating photosynthesis in dense cultures. The influence of Cb on light attenuation is strong, especially close to the illuminated surface. Over the first 2cm, the light intensities inside the culture decreased by 35% and 92% when Cb was 0.09gL−1 and 1.34gL−1 respectively. For cylindrical vessel the light distributions in dens culture are quite similar for both one-side and evenly illuminated. Furthermore, new quantitative model has been developed by adapting the Beer-Lambert model to describe light distribution inside algal cultures and predict local light intensity more accurately. The model was able to predict the sharp reduction in light intensity near the vessel surface that B-L model failed to predict; also the model was successfully simulating the experimental results under different conditions.

Differences between the Interactions of Linear and Tetrahedron-like Ditopic Guests with Cucurbit[8]uril: Steric Hindrance and Molecular Structure Play Dominant Roles.

A tetrahedron-like guest molecule (THV) with four ditopic arms, consisting of viologen (V) and hexylene moieties, was synthesized, and its interaction with cucurbit[8]uril (CB[8]) was investigated. As a reference, the interaction between CB[8] and an analogue of the arm of the linear ditopic guest (LHV) was first explored by 1 H NMR and UV/Vis spectroscopy. In this case, CB[8] was located on the hexylene moiety and resulted in the formation of a binary complex. However, when THV interacted with CB[8], despite having four arms with four hexylene moieties, only two CB[8] molecules were identified as located on the hexylene moieties; the other two CB[8] molecules resided on the V moieties. Great steric hindrance among the arms played a dominant role in the interaction between THV and CB[8]. Regardless of whether the guest molecule was THV or LHV, CB[8] moved to its V moiety (electron-deficient part) to form the charge-transfer complex upon the addition of a stopper containing a naphthol residue (electron-rich part). Guests LHV and THV were reduced to LHV+(+.) and THV+4(+.) upon the addition of sodium dithionite. Dimerization of LHV+(+.) was enhanced when CB[8] was present in less than 0.5 equivalents. In contrast, dimerization was suppressed when CB[8] was present in more than 0.5 equivalents. However, the V+. units of THV+4(+.) stacked intramolecularly because of the tetrahedron-like molecular structure of THV. The influence of CB[8] on the dimerization of THV+4(+.) was weaker than that on LHV+(+.) .

Influence of CB[n] complexation on the quenching of 2,4,6-triphenylpyrylium excited states by Fe2+ ions

This manuscript focuses on the influence that the addition of Fe2+ as electron donor quencher exerts on the photophysics of 2,4,6-triphenylpyrylium (TP+) depending on the formation or not of supramolecular inclusion complexes with cucurbit[n]uril (n: 7 or 8). 1H-NMR spectroscopy does not provide evidence supporting the formation of a ternary TP+@CB[n]–Fe2+ complex. Emission quenching studies indicate that the prevalent deactivation mechanism for the quenching of TP+ emission by Fe2+ is by increasing the ionic strength of the solution, with no evidence for the occurrence of dynamic quenching. Laser flash photolysis indicates that while the triplet excited state of TP+ is instantaneously quenched by Fe2+ in the absence of CB[n], formation of the TP+@CB[n] inclusion complex protects TP+ triplet excited state from quenching, an effect that is more pronounced in the case of CB[8] due to the deeper penetration and more complete encapsulation of the heterocyclic pyrylium core inside the larger CB[8] capsule.

Conductivity and Surface Tension Study for Cucurbit[7]uril Inclusion Complex of Cetyltrimethylammonium Chloride in Aqueous Solution

Conductivity and surface tension measurements have been carried out at temperatures between 298.15 K for cetyltrimethylammonium Chloride (CTAC) + H2O and CTAC + Cucurbit[7]uril (CB[7]) + H2O systems. The apparent critical micelle concentrations, the dissociation degree of the micelle, the hydrophobic contribution of the transfer free energy for the hydrocarbon chain of CTAC, the stoichoimetry and inclusion constants for the inclusion complex of CTAC with CB[7] have been determined. The influence of CB[7] and its complex on the micellization processes of CTAC is analyzed. It is shown that CB[7] partly screened the hydrophobic hydrocarbon chain of CTAC molecules from contact with the surrounding medium, and retarded the formation of CTAC micelles in a certain extent. CB[7] and the inclusion complex do not have any surface activity. The CB[7] and its complexes do not participate the formation of micelles of CTAC, and the complex has no effect on the micelle properties once the micelles are formed. The result suggests that β-CB[7] forms strong complex with CTAC, and the stoichoimetry is found to be 1:1, and the inclusion constants of CB[7]-CTAC complex are almost the same in different CB[7] solutions.

Protoplasmic streaming in the giant unicellular green algaAcetabularia mediterranea

The sensitivity of the dual intracellular transport system inAcetabularia mediterranea (Koop andKiermayer 1979 a) to cytochalasin B (CB, 10−5 mol), chlorisopropyl-N-phenylcarbamate (CIPC, 2.10−4 mol), and amiprophosmethyl (APM, 3.10−5 mol) has been studied by microcinematography. Vegetative cells before cap formation, 2–3 cm in length, and cells with a maximum sized cap, containing secondary nuclei, were used for the experiments. All intracellular movements ceased under the influence of CB, while in contrast to “headed streaming bands” and to the migration of the secondary nuclei, the movement of chloroplasts at “thin filaments” was found to be insensitive to Col, CIPC, and APM. All inhibitory effects of the drugs on protoplasmic streaming were completely reversible within a time of less than 10–20 minutes recovery from the drugs. The results suggest an involvement of microfilaments in all intracellular movements while, in addition, microtubules seem to be connected with the movement on “headed streaming bands”, including the migration of secondary nuclei.