Yongyang Song

A general strategy to synthesize chemically and topologically anisotropic Janus particles

A general emulsion interfacial polymerization strategy opens a new avenue for the large-scale synthesis of “god” Janus particles. Emulsion polymerization is the most widely used synthetic technique for fabricating polymeric particles. The interfacial tension generated with this technique limits the ability to tune the topology and chemistry of the resultant particles. We demonstrate a general emulsion interfacial polymerization approach that involves introduction of additional anchoring molecules surrounding the microdroplets to synthesize a large variety of Janus particles with controllable topological and chemical anisotropy. This strategy is based on interfacial polymerization mediated by an anchoring effect at the interface of microdroplets. Along the interface of the microdroplets, the diverse topology and surface chemistry features of the Janus particles can be precisely tuned by regulating the monomer type and concentration as well as polymerization time. This method is applicable to a wide variety of monomers, including positively charged, neutrally charged, and negatively charged monomers, thereby enriching the community of Janus particles.

A synergy effect between the hydrophilic PEG and rapid solvent evaporation induced formation of tunable porous microspheres from a triblock copolymer

A uniform Evansblue-loaded biodegradable amphiphilic poly(lactide-co-glycolide-b-ethylene glycol-b-lactide-co-glycolide)(PLGE) porous microsphere prepared by a synergy effect between the hydrophilic PEG and rapid solvent evaporation is reported. Our approach is based on the double emulsion (W/O/W) in which solvent evaporates rapidly. We show the introduction of hydrophilic PEG and rapid solvent evaporation play an important role in the formation of biodegradable porous microspheres. The microsphere size, pore size and distribution as well as drug loading efficiency can be well controlled by varying the polymer compositions. Meanwhile, the drug release behaviors of PLGE porous microspheres are also discussed.

Controllable drug release and effective intracellular accumulation highlighted by anisotropic biodegradable PLGE nanoparticles

Control of the stretching or compressing ratio of spherical nanoparticles (NPs) leads to a dramatic change in the shape and size of particles based on amphiphilic biodegradable poly(lactide-co-glycolide-b-ethylene glycol-b-lactide-co-glycolide) (PLGE) triblock copolymers. Drug release, endocytosis and intracellular accumulation tests on these anisotropic PLGE NPs show significantly enhanced properties in comparison with spherical NPs, indicating they are good candidates for drug delivery.

Recent progress in interfacial polymerization

Interfacial polymerization is one of the most important methods to fabricate polymer particles and membranes. As compared to bulk polymerization, interfacial polymerization is a type of step-growth polymerization that takes place at the interface of two immiscible phases, endowing the polymer materials with unique topological and chemical properties, such as anisotropic shapes, hollow structures or alternative surface chemistry. Herein, we summarize the recent progress in interfacial polymerization, generally based on the fabrication method and application field. First, two theory models of interfacial polymerization based on membrane and particles have been introduced. Second, five typical polymerization systems, i.e. liquid/monomer–solid (Lm–S), liquid/monomer–liquid (Lm–L), liquid/monomer–liquid/monomer (Lm–Lm), liquid/monomer-in-liquid (Lm-in-L), and liquid/monomer-in-liquid/monomer (Lm-in-Lm) systems, based on liquid–solid, liquid–liquid, and liquid-in-liquid emulsion interfaces, used in interfacial polymerization have been summarized. Then, three practical applications of synthetic materials, i.e. in electronic devices, separation, and cargo loading, prepared by interfacial polymerization have been shown. Finally, the current challenges and opportunities in interfacial polymerization have also been proposed and discussed.

Cell adhesive spectra along surface wettability gradient from superhydrophilicity to superhydrophobicity

Surface wettability is important to design biointerfaces and functional biomaterials in various biological applications. However, to date, it remains some confusions about how cells would response to the surfaces with different wettabilities. Herein, we systematically explore the adhesive spectra of cells to the surface with wettability gradient from superhydrophilicity to superhydrophobicity, clarifying the effect of wettability on cell adhesion. We envision that this study may provide valuable information for the design of biomedical implants with controllable cell adhesion, such as neural interface devices and flexible implant.

Engineering subcellular-patterned biointerfaces to regulate the surface wetting of multicellular spheroids

Studying the wetting behaviors of multicellular spheroids is crucial in the fields of embryo implantation, cancer propagation, and tissue repair. Existing strategies for controlling the wetting of multicellular spheroids mainly focus on surface chemistry and substrate rigidity. Although topography is another important feature in the biological micro-environment, its effect on multicellular spheroid wetting has seldom been explored. In this study, the influence of topography on the surface wetting of multicellular spheroids was investigated using subcellularpatterned opal films with controllable colloidal particle diameters (from 200 to 1,500 nm). The wetting of hepatoma carcinoma cellular (Hep G2) spheroids was impaired on opal films compared with that on flat substrates, and the wetting rate decreased as colloidal particle diameter increased. The decrement reached 48.5% when the colloidal particle diameter was 1,500 nm. The subcellular-patterned topography in opal films drastically reduced the cellular mobility in precursor films, especially the frontier cells in the leading edge. The frontier cells failed to form mature focal adhesions and stress fibers on micro-patterned opal films. This was due to gaps between colloidal particles leaving adhesion vacancies, causing weak cell–substrate adhesion and consequent retarded migration of Hep G2 spheroids. Our study manifests the inhibiting effects of subcellular-patterned topography on the wetting behaviors of multicellular spheroids, providing new insight into tissue wetting-associated treatments and biomaterial design.

Interfacially Polymerized Particles with Heterostructured Nanopores for Glycopeptide Separation

Porous polymer materials are extensively used for biomolecule separation. However, conventional homogeneous porous polymer materials cannot efficiently separate specific low-abundance biomolecules from complex samples. Here, particles fabricated by emulsion interfacial polymerization featuring heterostructured nanopores with tunable size are reported, which can be used to realize low-abundance glycopeptide (GP) separation from complex biofluids. The heterostructured surface inside the nanopores allows solvent-dependent local adsorption of biomolecules onto hydrophilic or hydrophobic regions. Low-abundance hydrophilic GPs in complex biofluids can be efficiently separated via the hydrophilic region of nanopores in low-polarity solvent after the hydrophobic region removes high-abundance hydrophobic proteins and non-glycopeptides in high-polarity solvent. It is expected that these particles with heterostructured nanopores can be used for separation of nucleic acids, saccharides, and proteins, and downstream clinical diagnosis.