Wormlike micelles have been observed and explained in a wide variety of different types of surfactants except sulfobetaine ones. Here, we first report branched worms formed by a C22-tailed amidosulfobetaine surfactant-3-(N-erucamidopropyl-N,N-dimethyl ammonium) propane sulfonate (EDAS). Increasing EDAS concentration in the semidilute region increases the viscosity by several orders of magnitude and forms viscoelastic micellar solution of entangled and branched worms. The intermicellar branching is proved by rheological methods and Cryo-TEM observation. Besides, the rheological experiments indicate that EDAS worms show some advantages such as low overlapping concentration, insensitive to inorganic salt, stable over the whole pH range.

Gold nanoparticles (AuNPs) have been widely studied and applied in the field of tumor diagnosis and treatment because of their special fundamental properties. In order to make AuNPs more suitable for tumor diagnosis and treatment, their natural properties and the interrelationships between these properties should be systematically and profoundly understood. The natural properties of AuNPs were discussed from two aspects: physical and chemical. Among the physical properties of AuNPs, localized surface plasmon resonance (LSPR), radioactivity and high X-ray absorption coefficient are widely used in the diagnosis and treatment of tumors. As an advantage over many other nanoparticles in chemicals, AuNPs can form stable chemical bonds with S-and N-containing groups. This allows AuNPs to attach to a wide variety of organic ligands or polymers with a specific function. These surface modifications endow AuNPs with outstanding biocompatibility, targeting and drug delivery capabilities. In this review, we systematically summarized the physicochemical properties of AuNPs and their intrinsic relationships. Then the latest research advancements and the developments of basic research and clinical trials using these properties are summarized. Further, the difficulties to be overcome and possible solutions in the process from basic laboratory research to clinical application are discussed. Finally, the possibility of applying the results to clinical trials was estimated. We hope to provide a reference for peer researchers to better utilize the excellent physicochemical properties of gold nanoparticles in oncotherapy.

Surface tension, fluorescence, and circular dichroism (CD) methods have been used to investigate the interaction between cationic gemini surfactant 1,2-ethane bis(dimethyldodecylammonium bromide) (C12C2C12) and proteins including bovine serum albumin (BSA) and gelatin. Surface tension measurements show that the complexes of gelatin--C12C2C12 form more easily than that of BSA--C12C2C12. Addition of C12C2C12 has a different effect not only on the polarity of the microenvironment in BSA and gelatin systems but also on their fluorescence spectra. It can be seen from far-UV CD spectra that the alpha-helical network of BSA is disrupted and its content decreases from 41.7% to 27.6% while the random coil content of gelatin increases from 53.0% to 55.9% with increasing C12C2C12 concentration. The results from near-UV CD spectra show that the binding of C12C2C12 induces changes of the microenvironment around the aromatic amino acid residues and disulfide bonds of BSA at high C12C2C12 concentrations.

A novel pH-switchable wormlike micellar system was prepared by mixing N-erucamidopropyl-N,N-dimethylamine and maleic acid with molar ratio of 2 : 1. The viscosity of the micellar solution is switchable via tuning the pH through the addition of minor acid or base. Such a system possesses the characteristics of a facile, rapid, cost-effective reversible process and recyclable cheaper materials.

No abstract

No abstract

A thermo-switchable surfactant gel with the property of gelation on heating was developed for the first time based on palmitylamidosulfobetaine. Micellar growth from globular aggregates to entangled worms upon heating is responsible for the thermal gelation.

Anionic wormlike micelles, particularly those formed by long-chain carboxylate surfactants, are relatively less documented though their cationic or zwitterionic counterparts are frequently reported. In this study, the wormlike micelles of sodium erucate (NaOEr), a C22-tailed anionic surfactant with a monounsaturated tail, in the presence of a tetraalkylammonium hydrotrope were investigated for the first time. The different effects of two hydrotropes, benzyl trimethyl ammonium bromide (BTAB) and tetramethyl ammonium bromide (TMAB), on the phase behavior and rheological behaviors were compared, and the influences of surfactant concentration and temperature on the rheological properties of NaOEr solutions were also examined. Both organic salts can lower the Krafft temperature of NaOEr solutions and thus improve its water solubility, but BTAB can make T(K) drop more sharply. At a fixed NaOEr concentration, less BTAB is demanded to induce the formation of viscoelastic solution and to obtain the maximum viscosity of NaOEr solution; at a constant salt concentration, with increasing NaOEr content, the NaOEr-BTAB system shows a larger zero-shear viscosity (η(0)), relaxation time, and plateau modulus but lower overlapping concentration than those of the NaOEr-TMAB system. The occurrence of maximum η(0) with increasing salt content for the NaOEr-BTAB system results from the formation of vesicles and L(3) phases, which were verified by cryo-TEM observations. η(0) shows an exponential decrease with increasing temperature; nevertheless it still remains above 10(3) mPa·s even at 90 °C.