Characteristics of the pH-regulated aggregation-induced enhanced emission (AIEE) and nanostructure orchestrate via self-assembly of naphthalenediimide–tartaric acid bola-amphiphile: role in cellular uptake

A naphthalene diimide–tartaric acid conjugate was successfully synthesized, and the influence of tartaric acid on the self-assembly of the NDI–TA scaffold was explored.

Thermoresponsive Structure and Dye Encapsulation of Micelles Comprising Bolaamphiphilic Quercetin Polyglycoside

A bolaamphiphile is a special member of amphiphilic molecules, which contains a hydrophobic skeleton and two water-soluble groups on both ends. Bolaamphiphiles form thermally stable associates in water under lower concentration than those of typical monoheaded amphiphiles, indicating the potential usefulness of bolaamphiphiles as the component of nanomaterials. However, the structural diversity of bolaamphiphiles is limited at this moment. We recently developed the synthesis of quercetin-3-O-polyglycoside (QP) as a new entry of bolaamphiphiles via a one-pot polymerization using sugar-based cyclic sulfite initiated by quercetin skeleton. Herein, we show the bolaamphiphilic properties of QP in detail. The micellization behaviors of QP are systematically investigated through comparison with those of quercetin (Que) and isoquercitrin (IQ) to evaluate the roles of glycone on the micellization of quercetin derivatives. The morphology of the micelles bearing QP is observed by cryo-transmission electron microscopy (cryo-TEM), suggesting the formation of bolaamphiphile-specific giant ribbon-like micelles in addition to spherical micelles. The thermoresponsive micellization behaviors are also discussed through the critical micelle concentration (CMC) values, the dynamic light scattering analyses at various temperatures, and thermal hysteresis of the micellizations. It is indicated that the polysaccharide chains integrated on the surface of micelles would serve as a steric protecting group to endow the micelles with kinetic stability. These results will shed light on natural glycoside skeletons to design a new class of micelles for advanced health applications in near future.

Synthesis of non-ionic bolaamphiphiles and study of their self-assembly and transport behaviour for drug delivery applications

A series of four bolaamphiphiles with different hydrophilic units has been synthesised. All the amphiphiles were well characterised from their physiochemical data. The aggregation tendency of newly synthesised amphiphiles was studied using fluorescence spectroscopy, dynamic light scattering (DLS), and cryogenic electron microscopy (cryo-TEM). Furthermore, their application as nanocarriers for hydrophobic guests was demonstrated by using two established standards, i.e. the dye Nile red and the drug nimodipine. A cytotoxicity and cellular uptake study has been carried out using A549 cells. Due to the presence of an ester linkage in PEG based bolaamphiphiles, a drug release study was performed in the presence of an immobilized enzyme Novozym-435 (a lipase).