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In this work, a pendant droplet-based sensor is developed for the rapid and label-free detection of acetylcholinesterase (AChE) and its inhibitors. The detection limit of AChE reaches 0.17 mU mL−1. The pIC50 values of AChE inhibitors such as neostigmine, rivastigmine and galantamine are determined to be 0.45 μM, 0.64 μM and 4.93 μM, respectively. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate the fabrication of organic/inorganic hybrid materials based on living self-assembly. First, polyoxometalate (Keggin-type phosphotungstic acid, H3PW12O40) (POM) as an inorganic constituent and surface active ionic liquid (1-dodecyl-3-carboxymethyl imidazolium bromide, [N-C12, N′-COOH-Im]Br) (SAIL) as an organic constituent, were utilized to construct organic/inorganic hybrid nanofibers via an ionic self-assembly approach. The time-dependent evolution of the morphology from nanoparticles to nanofibers was investigated using various techniques (e.g. SEM, TEM, and UV/Vis). Hydrogen bonds and hydrophobic interactions were proved to play a dominant role in the evolution process. Next, of particular interest, POM/[N-C12, N′-COOH-Im]Br hybrid nanofibers were also obtained via a living self-assembly process by mixing metastable nanoparticle building blocks and seeds generated via ultrasonication of nanofibers. It is observed that the metastable nanoparticles directly bound to the end of the seeds, resulting in the formation of nanofibers. This strategy reduces the morphological evolution time from 7 days to 24 h, which suggests that the introduction of seeds greatly lowers the energy barrier in the morphological evolution process. Our study indicates that organic/inorganic hybrid materials can be obtained via living self-assembly. This will facilitate the use of functional organic/inorganic hybrid materials in various applications. Furthermore, this study represents an important step toward artificial systems that can mimic biological systems. [ABSTRACT FROM AUTHOR]

Multivalent interactions remain difficult to be characterized and consequently controlled, particularly on a macroscopic scale. Using force-induced remnant magnetization spectroscopy (FIRMS), we have resolved the single-, double-, and triple-biotin–streptavidin interactions, multivalent DNA interactions and CXCL12–CXCR4 interactions on millimetre-scale surfaces. Our results establish FIRMS as a viable method for systematic resolution and controlled formation of multivalent interactions. [ABSTRACT FROM AUTHOR]

Constructing multiple-response smart materials is a very interesting and challenging task in materials science. Here we employed an ionic self-assembly (ISA) strategy to fabricate pH- and temperature-responsive supramolecular materials with controllable fluorescence emission properties by using charged Congo red (CR) and an oppositely charged COOH-functionalized imidazolium-based surface active ionic liquid (SAIL), N-decyl-N′-carboxymethyl imidazolium bromide ([N-C10, N′-COOH-Im]Br). One-dimensional (1D) slender fibers were obtained in aqueous solution at pH 3.2 by the self-assembly of CR/[N-C10, N′-COOH-Im]Br (molar ratio = 1 : 2) at room temperature. Noteworthy is that two-dimensional (2D) planar structures, viz. bamboo leaf-like, spindly, discoid and rectangular structures, were then formed only by further changing the pH of the solution. Of particular interest is that the transition between 1D and 2D structures is pH reversible. We also found that the slender fibers could aggregate into fiber bundle structures with increasing temperature. In addition, fluorescence emission of the obtained 1D and 2D materials can be controlled by adjusting the morphologies of the aggregates. The electrostatic and hydrophobic interactions, in concert with π–π stacking between Congo red and [N-C10, N′-COOH-Im]Br molecules, were regarded as the main driving forces. The dimer-type π–π stacking existing among CR molecules was testified by DFT calculations. [ABSTRACT FROM AUTHOR]