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The topical application of probiotic metabolites has shown positive effects in the treatment of skin diseases; however, the effectiveness is strain dependent. Comparing the pathogen inhibitory effects of probiotic strains with different genetic backgrounds and analyzing their key metabolites can provide insights about the potential of applying probiotics for skincare. In this study, we investigated the fermentation growth inhibition of 18 commercial probiotic strains on the skin pathogens Malassezia furfur (M. furfur) and Cutibacterium acnes (C. acnes) in vitro. We found that most Bifidobacterium animalis subsp. lactis (B. lactis) and Lacticaseibacillus rhamnosus (L. rhamnosus) strains exhibited strong inhibition of M. furfur and C. acnes, which lasted up to 100 h. The main antibacterial metabolites observed were molecules below 10,000 Da in molecular weight, including peptides and organic acids (lactic acid, acetic acid, propionic acid, and butyric acid). The synergistic effect of organic acid combinations lowered the minimum inhibitory concentration (MIC). The composition of these antimicrobial metabolites varied among strains, which demonstrated the strain-dependent pathogenic inhibitory effects. This study provides insights into the application potential of using probiotic metabolites against seborrheic dermatitis and acne-related pathogenic bacteria.

Abstract Graphene oxide (GO), a novel carbon‐based nanomaterial, has been significantly developed and investigated during the past decade in the fields of material science and chemistry. GO is essentially one‐atom thick, but the lateral dimension can reach to dozens of microns, resulting in a unique 2D layered structure. This allows for oxygen‐containing functional groups to be grafted on the sheets, which give GO a unique amphiphilicity and enables it to self‐assemble at two‐phase interfaces. This characteristic provides significant potential for the development of functional interfacial materials with promising performances, including the synthesis of large area interfacial membranes, GO‐based coating with self‐healing abilities, and functional GO‐based emulsions. In this review, the interfacial assembly behaviors of GO and functionalized‐GO at the air–liquid, liquid–liquid, and liquid–solid interfaces are discussed to further understand the properties and applications of GO. The synthesis of different composites using these interfacial properties is also discussed. The application progress of GO composite materials that are prepared based on their interfacial properties is also illustrated, and possible challenges are proposed.

In this work, three different aqueous solutions containing imidazole-based ILs with different alkyl chain lengths ([Cnmim]Br, n = 2, 6, 12) were adopted as the medium for the synthesis of ionic liquid-polypyrrole (IL-PPy) composites. Herein, the ILs undertook the roles of the pyrrole solvent, the media for emulsion polymerization of PPy and PPy dopants, respectively. The electrochemical performances of the three IL-PPy composites on a glassy carbon electrode (GCE) were investigated by electrochemical experiments, which indicated that [C12mim]Br-PPy (C12-PPy) composites displayed better electrochemical performance due to their larger surface area and firmer immobilization on the GCE. Further, C12-PPy/GCE were decorated with Au microparticles by electrodeposition that can not only increase the conductivity, but also immobilize sufficient biomolecules on the electrode. Then, the obtained C12-PPy-Au/GCE with outstanding electrochemical performance was employed as a horseradish peroxidase (HRP) immobilization platform to fabricate a novel C12-PPy-Au-HRP/GCE biosensor for H2O2 detection. The results showed that the prepared C12-PPy-Au-HRP/GCE biosensor exhibited high sensitivity, fast response, and a wide detection range as well as low detection limit towards H2O2. This work not only provides an outstanding biomolecule immobilization matrix for the fabrication of highly sensitive biosensors, but also advances the understanding of the roles of ILs in improving the electrochemical performance of biosensors.

Diblock copolymers (mPEG-b-PDPA), which were designed to possess pH-sensitivity as well as amphipathy, were used as an intelligent lock in the liposomal membrane. The so-called pH-sensitive liposomes were prepared by simple mixing of the synthesized mPEG-b-PDPA with phospholipids and cholesterol. Fluorescence polarization at pH 7.4 showed that the membrane stability of the hybrid liposome was significantly increased compared with the pure liposome. Therefore, in the neutral environment, the leakage of doxorubicin (DOX) was inhibited. However, when pH decreased to 6.0, DOX release rate increased by 60% due to the escape of copolymer. The effects of the membrane composition and the PDPA segment length on bilayer membrane functions were investigated. These results revealed that the synthesized copolymers increased the difference in DOX cumulative release between pH 7.4 and 6.0, that is, improved the pH-controllability of the drug release from hybrid liposomes.

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We propose a direct method to measure the equilibriumand dynamicsurface properties of surfactant solutions with very low criticalmicellar concentrations (CMC) using a pendant drop tensiometer. Westudied solutions of the nonionic surfactant hexaethylene glycol monododecylether (C12E6) and of the ionic surfactant hexadecyltrimethyl ammonium bromide (CTAB) with concentrated sodium bromide(NaBr). The variation of the surface tension as a function of surfaceconcentration is obtained easily without the need for complex modelsand compares well with the result obtained using the Gibbs adsorptionequation. The time-dependent surface concentration of each surfactantwas also measured, and the adsorption process was found to be diffusion-controlled.The diffusion coefficients of the two surfactants can be extractedfrom the data and were found in very good agreement with literaturevalues, further validating the method. [ABSTRACT FROM AUTHOR]

A reaction density functional theory (R-DFT) is developed for chemical reactions in confined space by integrating reaction thermodynamics and DFT for chain fluids. The theory is applied to investigate DNA melting in slit pores, with nucleotides represented by coarse-grained charged Lennard-Jones particles. Three types of slit pores are considered for DNA melting: repulsive pore, attractive pore, and under electric field. In repulsive pores, the melting temperature increases slightly with reducing pore width, and the increase magnitude is nearly the same for DNA of different chain lengths. The double-strand DNA (dsDNA) and single-strand DNA (ssDNA) are located in the slit center, particularly for long DNA due to the effect of configuration entropy. In attractive pores, the melting temperature increases with increasing wall−fluid interaction. The DNA chains are preferentially adsorbed near the slit walls with a strong wall−fluid interaction. Under electric field, the melting temperature increases slightly and is more distinct for shorter DNA. [ABSTRACT FROM AUTHOR]

The effect of ionic liquids CnmimBr (n= 4, 6, 8) on the properties of cationic Gemini surfactant trimethylene-1,3-bis(dodecyl ammonium bromide) (Gemini 12-3-12) aqueous solution was investigated. The critical micelle concentration (cmc) of Gemini 12-3-12 solutions containing different amounts of ionic liquids were obtained by measurement of surface tension. The composition of mixed micelle and the interaction parameter between ionic liquids and Gemini 12-3-12 were calculated by Rubingh regular solution model; the effective area of Gemini 12-3-12 molecule at air/water interface was calculated by Gibbs adsorption isotherm. The results show that the addition of ionic liquid has important effect on the properties of surfactant aqueous solution. The cmc of surfactant solution and the effective area of surfactant molecules at the air/water interface vary parabolically with the addition of ionic liquids owing to the two extra opposite effects of ionic liquids in surfactant aqueous solutions besides counterion effect, participation of micelles formation, and the effect on the properties of solvent. The effect of ionic liquids on surfactant solution can be regarded as the comprehensive effects of inorganic salt, cosurfactant, and cosolvent on surfactant solution. [ABSTRACT FROM AUTHOR]

Abstract  The effect of added salts (NaCl, KCl and NaBr) on the aqueous two-phase system (ATPS) formed in mixtures of Gemini(12-3-12, 2Br−)/sodium dodecyl sulfate/polyethylene glycol has been investigated. Phase diagrams of the aqueous systems containing Gemini(12-3-12, 2Br−), sodium dodecyl sulfate (SDS), polyethylene glycol(PEG) and a salt have been determined experimentally at 313.15 K. The results indicate that the addition of salts not only induces the appearance of ATPS-A (in which anionic surfactant is in excess), shortens the phase separation time, enlarges the regions of ATPS-C (in which cationic surfactant is in excess), and decreases the minimum concentration required for forming an ATPS, but also alters the matching between anionic and cationic surfactants. Extractive experiments also showed that these salts notably enhance the extraction ability of ATPS; the Gemini-rich phase exhibits prominent cohesive action with xylenol orange, regardless of whether or not it is the upper phase or the lower phase. [ABSTRACT FROM AUTHOR]