Effect of types of solid lipids on the physicochemical properties and self-aggregation of amphotericin B loaded nanostructured lipid carriers(NLCs)

Amphotericin B (Am B), a polyene antibiotic, is one of the gold standards for the treatment of systemic fungal infections and leishmaniasis. Nowadays, only intravenous administration of Am B has been available;because Am B is poorly absorbed from the gastrointestinal (GI) tract due to its low aqueous solubility. Currently, 2 forms of Am B are available.

SYNTHESIS AND FLUORESCENCE STUDY OF SELF-AGGREGATION PROCESS IN AQUEOUS SOLUTION OF HYDROPHOBILIZED POLYSACCHARIDE

Cholesterol modified dextran (CHD) having self-aggregation or self-assembly property was synthesized from cholesterol and 1,6-hexyldiisocyanate. The degree of substitution of cholesteryl moiety in dextran main line is 3-5 cholesterols the 100 glucose units. We have prepared water solution of CHD using probe type sonifier and N-Phenyl-α-naphthylamine (PNA) as a fluorescent probe to study CHD self-aggregate process .For each solution of two samples, we found that the maximum emission of PNA in CHD solution was shifted to the lower wavelength and the intensity drastically increased above a critical CHD concentration. This change corresponds to the formation of micelle-like clusters self-aggregated by the cholesterol moiety once the CHD concentration exceeds 0.01 mg/ml.

Efficient and stable inverted perovskite solar cells enabled by inhibition of self-aggregation of fullerene electron-transporting compounds

Fullerene-based electron-transporting layers(ETLs)significantly influence the defect passivation and device performance of inverted perovskite solar cells(PSCs).However,theπ-cage structures of fullerenes lead to a strong tendency to self-aggregate,which affects the long-term stability of the corresponding PSCs.Experimental results revealed that[6,6]-phenyl-C61-butyric acid methyl ester(PCBM)-based ETLs exhibit a certain degree of self-aggregation that affects the stability of the device,particularly under continuous irradiation stress.To modulate the aggregation behavior,we replaced a methyl hydrogen of PCBM with a phenyl group to yield[6,6]-phenyl-C61-butyric acid benzyl ester(PCBB).As verified through X-ray crystallography,this minor structural modification results in more non-covalent intermolecular interactions,which effectively enhanced the electron-transporting ability of the PCBB-based ETL and led to an efficiency approaching 20%.Notably,the enhanced intermolecular forces of PCBB suppressed its self-aggregation,and the corresponding device showed significantly improved stability,retaining approximately 90%of its initial efficiency after 600 h under one-sun irradiation with maximum power point tracking.These findings provide a viable approach for the design of new fullerene derivatives to tune their intermolecular interactions to suppress self-aggregation within the ETL for highperformance PSCs.

Nitrogen-doped hierarchical porous carbon from polyaniline/silica self-aggregates for supercapacitor

In this paper, nitrogen-doped hierarchical porous carbon(N-HPC) was prepared from polyaniline(PANI)/silica self-aggregates. H-bonding between N\\H groups in aniline/PANI and \\OH groups in nano silica template led to a self-assembly type, which enabled the formation of uniform N-HPC nanoparticles. Silica self-aggregates provided macroporous channels resulted in a decreased diffusion distance. After removing the hard template,the N-HPC had a high surface area(899 m^2·g^(-1)). Owing to two co-existed synergetic energy-storage mechanisms and the hierarchical porous structure, the obtained N-HPC exhibited a high specific capacitance of 218.75 F·g^(-1) at 0.5 A·g^(-1), compared with the nonporous nitrogen-doped carbon(N-C) derived from pure PANI. Moreover, the N-HPC electrode demonstrated excellent cycle life, retaining 99% of its initial specific capacitance after 1000 cycles.

Self-aggregating behavior of poly(4-vinyl pyridine)and the potential in mitigating sand production based onπ-πstacking interaction

Unconsolidated sandstone reservoirs are most susceptible to sand production that leads to a dramatic oil production decline.In this study,the poly(4-vinyl pyridine)(P_(4)VP)incorporated with self-aggregating behavior was proposed for sand migration control.The P_(4)VP could aggregate sand grains spontaneously throughπ-πstacking interactions to withstand the drag forces sufficiently.The influential factors on the self-aggregating behavior of the P_(4)VP were evaluated by adhesion force test.The adsorption as well as desorption behavior of P_(4)VP on sand grains was characterized by scanning electron microscopy and adhesion force test at different pH conditions.The result indicated that the pH altered the forms of surface silanol groups on sand grains,which in turn affected the adsorption process of P_(4)VP.The spontaneous dimerization of P_(4)VP molecules resulting from theπ-πstacking interaction was demonstrated by reduced density gradient analysis,which contributed to the self-aggregating behavior and the thermally reversible characteristic of the P_(4)VP.Dynamic sand stabilization test revealed that the P_(4)VP showed wide pH and temperature ranges of application.The production of sands can be mitigated effectively at 20-130℃ within the pH range of 4-8.

Self-healing elastomer modified proppants for proppant flowback control in hydraulic fracturing

To address proppant flowback issues during post-fracturing treatments and production,self-healing elastomer modified proppants(SMPs)are proposed.Owing to their inherent self-aggregation behavior,the SMPs can aggregate together spontaneously to prevent proppant flowback and increase the pack porosity.It is noteworthy that the SMPs have a firm and dry self-healing elastomer(SE)coating,making their storage,transport and use as conventional proppants possible.The SE synthesized through polymerization is rich in amidogens and carbonyl groups as characterized by Fourier transform infrared spectroscopy and the proton nuclear magnetic resonance.Thermal and thermomechanical properties of the SE coating are revealed by the thermogravimetric analysis,the differential scanning calorimetry and the rheological tests.The self-aggregation behavior of the SMPs is demonstrated by the adhesion force tests.The reversible hydrogen bonding interactions in SE coating contribute to the self-aggregation behavior of the SMPs,which is revealed by the thixotropy test and the FTIR analysis at different temperatures.With the self-aggregation behavior,the crushed proppants can aggregate in situ to form a stable structure again and therefore reduce the threat of narrowing down the fracture and proppant flowback,which has an important practical significance during oil and gas production.

Thermodynamical Approach for Choosing the Carrier System for Tetraantraquinoporphyrazines

On the example of tetraantraquinoporphyrazines—potential photosensitizers for photodynamic therapy, thermodynamic approach to the choice of exogenous transport system was demonstrated. By means of isothermal titration calorimetry and electron absorption spectroscopy, the state of TAP in aqueous solutions was studied. The possibility of aggregation equilibrium displacement due to the pyridine adding was evaluated.

Preparation and Charaterization of Self-assembled Nanoparticles Based on Linolenic-acid Modified Chitosan

Chitosan was modified by conjugating coupling with linolenic acid through the 1-ethyl-3-（3-dimethylami- nopropyyl） carbodiimide （EDC）-mediated reaction. The degree of substitution 1.8% （ i.e. 1.8 linolenic acid group per 100 anhydroglucose units） was measured by ^1H NMR. The critical aggregation concentration （CAC） of the self-aggregate of hydrophobically modified chitosan was determined by measuring the fluorescence intensity of the pyrene as a fluorescent probe. The CAC value in phosphate-buffered saline （PBS） solution （pH 7.4） was 5 × 10^-2 mg mL^-1. The average particle size of selfaggregates of hydrophobically modified chitosan in PBS solution （pH7.4） was 210.8 nm with a unimodal size distribution ranging from 100 to 500 nm. Transmission electron microscopy （TEM） study showed that the formation of near spherical shape nanoparticles has enough structural integrity. The loading ability of hydrophibically modified chitosan （LA-chitosan） was investigated by using bovine serum albumin （BSA） as the model. The loading capacity of self-aggregated nanoparticles increases （ 19.85 % ± 0.04 % to 37.57 % ± 0.25 % ） with the concentration of BSA （0.1-0.5 mg mL^-1 ）.

Assembly-enhanced triplet-triplet annihilation upconversion in the aggregation formed by Schiff-base Pt(Ⅱ) complex grafting-permethyl-β-CD and 9,10-diphenylanthracence dimer

Water-soluble triplet sensitizer with permethyl-β-cyclodextrin(PMCD)grafting on a Schiff-base Pt(II)complex(Pt-2),in which PMCD unit serves as a host for binding the acceptors and the Schiff-base Pt(II)complex serves as a triplet sensitizer,was synthesized to investigate the effect of supramolecular complexation and assembly on the triplet-triplet annihilation upconversion emission in water.9,10-Diphenylanthracence(DPA)carboxylate(A-1)and its dimer(A-2)in which two DPA carboxylate were covalently linked with an alkyl chain were synthesized as triplet acceptors which also play a role of guest molecules for PMCD.A-1 and A-2 showed high affinity with PMCD,and A-2 can readily aggregate in water and form micron sized assemblies due to the hydrophobic effect andπ-πstacking of anthracene core in A-2.The efficiency of TTA-UC was demonstrated to be enhanced by a synergistic effect of host-guest complexation of Pt-2 with A-2 and the self-aggregation of the acceptor A-2,which facilitated the energy transfer and energy fusion among donor and acceptor.