Structural Engineering and Optimization of Zwitterionic Salts for Expeditious Discovery of Thermoresponsive Materials.

This work reported the discovery of N-triflimide (NTf)-based zwitter-ionic liquids (ZILs) that exhibit UCST-type phase transitions in water, and their further structural optimization in fine-tuning polarity to ultimately afford newfangled thermosensitive materials carrying attractive and biocompatible Tc values that clearly demonstrated the true value of the tunability of ZIL structure. This research established that with non-aromatic, acyclic ZILs as small-molecule thermoresponsive materials, their mixing and de-mixing with water triggered by temperatures are entirely reversible.

Zwitterionic ionic liquids modulating two-dimensional hierarchically porous zeolitic imidazolate framework composites.

HYPOTHESIS: Two-dimensional hierarchically porous zeolitic imidazolate frameworks (H-ZIFs) show great promising applications in catalysis, gas separation, energy storage and sensing. Herein, a facile ionic-liquid-modulation approach is proposed for constructing H-ZIFs nanosheets with tunable thickness. EXPERIMENTS: Sulfo-functionalized zwitterionic ionic liquids (SFIL) have been designed as monodentate ligands to direct the formation of microporous nanosheets (ZIF-SFIL) in aqueous solution. Anions of SFIL have been tuned to modulate the coordination environment, enabling the control of the structure, thickness and pores of the nanosheets. FINDINGS: SFIL is demonstrated to pre-coordinate with Zn(II) to induce micropores with high specific surface areas (up to 1176 m2·g-1) and accelerate the nucleation of crystals. The BF4- anion serves as a competitive ligand to partially replace SFIL to cause structural defects, thus yielding hierarchically porous ZIF-SFIL nanosheets with high specific surface areas (270-466 m2·g-1) and variable thicknesses (from ca. 58 nm to ca. 455 nm). Benefiting from the versatile designability and multifunctionality of ionic liquids, the strategy in this work offers a facile approach for designing and constructing multifunctional materials with hierarchical pores.

Crosslinked zwitterionic polymeric ionic liquid-functionalized nitinol wires for fiber-in-tube solid-phase microextraction and UHPLC-MS/MS as an amyloid beta peptide binding protein assay in biological fluids.

Alzheimer disease (AD) is a neurodegenerative disorder characterized by extracellular accumulation of amyloid-ß peptide (Aß) in the brain interstitium. Human serum albumin (HSA) highly binds to Aß in blood plasma and is thought to inhibit plaque formation in peripheral tissue. Thus, the evaluation of albumin binding to Aß is an important key to understand the dynamics of these molecules in the biological system of patients with AD. In this work, a fiber-in-tube solid-phase microextraction (fiber-in-tube SPME) and ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to estimate Aß fraction binding to HSA in cerebrospinal fluid (CSF) and plasma samples. Crosslinked zwitterionic polymeric ionic liquid (zwitterionic PIL)-coated nitinol wires were developed and packed into a polyether ether ketone (PEEK) capillary for a fiber-in-tube SPME and UHPLC-MS/MS method. Zwitterionic PIL sorbent was synthetized from 1-vinyl-3-(butanesulfonate)imidazolium ([VIm+C4SO3-]) and 1,12-di(3-vinylimidazolium)dodecane dibromide ([(VIm)2C12]2[Br]) monomers by in-situ thermally-initiated polymerization. Morphological characterization by scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed a decrease in the surface roughness of the nitinol wires from ∼17 nm to 1 nm after the in-situ polymerization. The zwitterionic PIL sorbent selectively preconcentrates Aß through a two-pronged interaction mechanism. The fiber-in-tube SPME and UHPLC-MS/MS method presented lower limits of quantification (LLOQ) of 0.4 ng mL-1 for Aß38 and 0.3 ng mL-1 for Aß40 and Aß42, a linear range from LLOQ values to 15 ng mL-1 with coefficients of determination higher than 0.99, precision with coefficient of variation (CV) values ranging from 2.1 to 7.3% and accuracy with relative standard deviation (RSD) values from -0.3 to 7.4. This method was successfully applied to evaluate the binding of HSA to Aß in cerebrospinal fluid (CSF) and plasma samples.