Weakly Ionically Bound Thermosensitive Hyperbranched Polymers

We synthesized novel amphiphilic hyperbranched polymers (HBPs) with variable contents of weakly ionically tethered thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) macrocations in contrast to traditional covalent linking. Their assembling behavior was studied below and above the lower critical solution temperature (LCST). The HBPs underwent a morphological transition under changing temperature and ionic strength due to the LCST transition of PNIPAM and the reduction in the ionization degree of terminal ionic groups, respectively. We suggest that, in contrast to traditional branched polymers, ionically linked PNIPAM macrocations can reversibly disassociate from the sulfonate groups and form mobile coronas, endowing the dynamic micellar morphologies. In addition, assembly at the air-water interface confined PNIPAM macrocations and resulted in the formation of heterogeneous Langmuir-Blodgett (LB) monolayers with diverse surface morphologies for different peripheral compositions with circular domains formed in the condensed state. The HBPs with 25% PNIPAM showed larger and more stable circular domains that were partially preserved at high compression than those of HBPs with 50% PNIPAM. Moreover, the LB monolayers showed variable surface mechanical and surface charge distribution, which can be attributed to net dipole redistribution caused by the behavior of mobile PNIPAM macrocations and core sulfonate groups.

Direct electrochemistry of covalently immobilized hemoglobin on a naphthylimidazolium butyric acid ionic liquid/MWCNT matrix

Monitoring the concentration levels of hydrogen peroxide (H₂O₂) is significant in both clinical and industrial applications. Herein, we develop a facile biosensor for the detection of H₂O₂ based on direct electron transfer of hemoglobin (Hb), which was covalently immobilized on a hydrophobic naphthylimidazolium butyric acid ionic liquid (NIBA-IL) over a multiwalled carbon nanotube (MWCNT) modified glassy carbon electrode (GCE) to obtain an Hb/NIBA-IL/MWCNT/GCE. Highly water-soluble Hb protein was firmly immobilized on NIBA-IL via stable amide bonding between the free NH₂ groups of Hb and COOH groups of NIBA-IL via EDC/NHS coupling. Thus fabricated biosensor showed a well resolved redox peak with a cathodic peak potential (E_pc) at -0.35 V and anodic peak potential (E_pa) at -0.29 V with a formal potential (E°') of -0.32 V, which corresponds to the deeply buried Fe^III/Fe^II redox centre of Hb, thereby direct electrochemistry of Hb was established. Further, the modified electrode demonstrated very good electrocatalytic activity towards H₂O₂ reduction and showed a wide linear range of detection from 0.01 to 6.3 mM with a limit of detection and sensitivity of 3.2 μM and 111 μA mM^-1 cm^-2, respectively. Moreover, the developed biosensor displayed high operational stability under dynamic conditions as well as during continuous potential cycles and showed reliable reproducibility. The superior performance of the fabricated biosensor is attributed to the effective covalent immobilization of Hb on the newly developed highly conducting and biocompatible NIBA-IL/MWCNT/GCE platform.

Self-assembly and functionalization of alternating copolymer vesicles

This work reports novel alternating copolymer vesicles and their facile functionalization with carboxyl and amino groups through click copolymerization.

Ionic Self-Assembly of a Giant Vesicle as a Smart Microcarrier and Microreactor

Giant vesicles (1-10 μm) were constructed via a facile ionic self-assembly (ISA) strategy using an anionic dye Acid Orange II (AO) and an oppositely charged ionic-liquid-type cationic surfactant 1-tetradecyl-3-methylimidazolium bromide (C14mimBr). This is the first report about preparing giant vesicles through ISA strategy. Interestingly, the giant vesicle could keep the original morphology during the evaporation of solvent and displayed solid-like properties at low concentration. Moreover, giant vesicles with large internal capacity volume and good stability in solution could also be achieved by increasing the concentrations of AO and C14mimBr which contributed to the increase of the other noncovalent cooperative interactions. In order to facilitate comparison, a series of parallel experiments with similar materials were carried out to investigate and verify the driving forces for the formation of these kinds of giant vesicles by changing the hydrophobic moieties or the head groups of the surfactants. It is concluded that the electrostatic interaction, hydrophobic effect and π-π stacking interaction play key roles in this self-assembly process. Importantly, the giant vesicles can act as a smart microcarrier to load and release carbon quantum dot (CQD) under control. Besides, the giant vesicles could also be applied as a microrector to synthesize monodispersed Ag nanoparticles with diameter of about 5-10 nm which exhibited the ability to catalyze reduction of 4-nitroaniline. Therefore, it is indicated that our AO/C14mimBr assemblies hold promising applications in the areas of microencapsulation, catalyst support, and lightweight composites owing to their huge sizes and large microcavities.

Dendritic Polymers for Theranostics

Dendritic polymers are highly branched polymers with controllable structures, which possess a large population of terminal functional groups, low solution or melt viscosity, and good solubility. Their size, degree of branching and functionality can be adjusted and controlled through the synthetic procedures. These tunable structures correspond to application-related properties, such as biodegradability, biocompatibility, stimuli-responsiveness and self-assembly ability, which are the key points for theranostic applications, including chemotherapeutic theranostics, biotherapeutic theranostics, phototherapeutic theranostics, radiotherapeutic theranostics and combined therapeutic theranostics. Up to now, significant progress has been made for the dendritic polymers in solving some of the fundamental and technical questions toward their theranostic applications. In this review, we briefly summarize how to control the structures of dendritic polymers, the theranostics-related properties derived from their structures and their theranostics-related applications.

Supramolecular Architectures of Dendritic Amphiphiles in Water

Dendritic molecules are an exciting research topic because of their highly branched architecture, multiple functional groups on the periphery, and very pertinent features for various applications. Self-assembling dendritic amphiphiles have produced different nanostructures with unique morphologies and properties. Since their self-assembly in water is greatly relevant for biomedical applications, researchers have been looking for a way to rationally design dendritic amphiphiles for the last few decades. We review here some recent developments from investigations on the self-assembly of dendritic amphiphiles into various nanostructures in water on the molecular level. The main content of the review is divided into sections according to the different nanostructure morphologies resulting from the dendritic amphiphiles' self-assembly. Finally, we conclude with some remarks that highlight the self-assembling features of these dendritic amphiphiles.

Acid–base indicators for non-polar solvents via anion-exchange of polymeric ionic liquids with anionic dyes

This work reports the synthesis of acid–base indicators based on linear polymeric ionic liquids and their indicating behaviors in non-polar solvents.