Amphiphilic colloidal surfactants based on electrohydrodynamic co-jetting

Bioinspired design of amphiphilic particles with tailored compartments for dual-drug controlled release

Inspired by the phenomenon of water droplets hanging over rose petals, we propose a green interfacial self-assembly strategy to construct amphiphilic particles with controllable compartments for dual-drug encapsulation and controlled release. The method involves fabrication of "sticky" superhydrophobic materials, assembling superhydrophilic hydrogel beads with "sticky" superhydrophobic material into an amphiphilic particle, and amphiphilicity induced self-organization of several small amphiphilic particles into a large-sized amphiphilic multicompartmental particle. With the employment of this approach, amphiphilic particles with tailored sizes, controllable morphology, and tunable numbers of compartments are successfully constructed. The formation process and the underlying principle are further clarified. We finally investigate the potential application of the amphiphilic multicompartmental particles to load both hydrophilic and hydrophobic species in separated domains and release them in a controllable manner without interference. This novel approach may offer a new route to generate amphiphilic materials for the purpose of multidrug combination therapy, multiple-cell encapsulation, and so on.

Oppositely Charged, Stimuli-Responsive Anisotropic Nanoparticles for Colloidal Self-Assembly

Anisotropic nanoparticles (ANPs) composed of distinct compartments are of interest as advanced materials because they offer unique physicochemical properties controlled by polymer composition, distribution of functional groups, and stimuli responsiveness of each compartment. Furthermore, colloidal self-assembly of ANPs via noncovalent interactions between compartments can create superstructures with additional functionality. In this study, ANPs with two compartments composed of oppositely charged and thermally responsive ternary copolymers were prepared using electrohydrodynamic cojetting. One compartment was composed of poly( N-isopropylacrylamide- co-stearyl acrylate- co-allylamine), which is positively charged in aqueous solution at pH 7, and the other compartment was composed of poly( N-isopropylacrylamide- co-stearyl acrylate- co-acrylic acid), which is negatively charged. The ANPs were stabilized in aqueous solution by physical cross-linking because of hydrophobic interactions between the 18-carbon alkyl chains of their stearyl acrylate moieties and self-assembled into supracolloidal nanostructures via electrostatic interactions. Colloidal self-assembly and thermal responsiveness were controlled by compartment charge density and solution ionic strength. The supracolloidal nanostructures exhibited both the intrinsic temperature-responsive properties of the ANPs and collective properties from self-assembly. These multifunctional, stimuli-responsive nanostructures will be useful in a variety of applications, including switchable displays, drug delivery carriers, and ion-sensitive gels.

Compartmentalized Microhelices Prepared via Electrohydrodynamic Cojetting

Anisotropically compartmentalized microparticles have attracted increasing interest in areas ranging from sensing, drug delivery, and catalysis to microactuators. Herein, a facile method is reported for the preparation of helically decorated microbuilding blocks, using a modified electrohydrodynamic cojetting method. Bicompartmental microfibers are twisted in situ, during electrojetting, resulting in helical microfibers. Subsequent cryosectioning of aligned fiber bundles provides access to helically decorated microcylinders. The unique helical structure endows the microfibers/microcylinders with several novel functions such as translational motion in response to rotating magnetic fields. Finally, microspheres with helically patterned compartments are obtained after interfacially driven shape shifting of helically decorated microcylinders.

Fast swelling strategy for flower-like micro-sized colloidal surfactants with controllable patches by regulating the Tg of seed particles

We are reporting an efficient fast swelling procedure by regulating the glass transition temperature T_g of poly(glycidyl methacrylate) (PGMA) seed particles via copolymerization with n-butyl acrylate (nBA).

Janus particle synthesis via aligned non-concentric angular nozzles and electrohydrodynamic co-flow for tunable drug release

A novel non-concentric tilted angle nozzle was designed and manufactured to enable the synthesis of tunable Janus particles. The effect of processing parameters and device configurations on particle structure and dual drug release were explored.

Applications of tunable resistive pulse sensing

This Review focusses on the recent surge in applied research using tunable resistive pulse sensing, a technique used to analyse submicron colloids in aqueous solutions on a particle-by-particle basis.

Platelet Janus particles with hairy polymer shells for multifunctional materials

A novel approach is developed for the large-scale synthesis of Janus particles with platelet geometry and dense polymer shells by employing simultaneous "grafting from" of hydrophilic and hydrophobic polymers using surface-induced ATRP in emulsion. The method is based on the fabrication of an emulsion consisting of a water solution of a hydrophilic monomer and a solution of a hydrophobic monomer in an organic solvent, which is stabilized by initiator-modified kaolinite particles. Two polymers are grafted simultaneously on the opposite faces of the kaolinite particle during polymerization. The synthesized particles have a clear Janus character and are highly efficient for the stabilization of emulsions. Because of its simplicity, the method can readily be upscaled for the synthesis of large amounts of Janus particles, up to several grams.

Spatioselective growth of metal-organic framework nanocrystals on compositionally anisotropic polymer particles

Selective growth of metal organic framework materials on the surface of compartmentalized polymer microparticles is achieved by electro-hydrodynamic co-jetting, selective surface modification, and anisotropic crystal growth.