A novel core-shell microcapsule system is developed in this study to mimic the miniaturized 3D architecture of pre-hatching embryos with an aqueous liquid core of embryonic cells and a hydrogel-shell of zona pellucida. This is done by microfabricating a non-planar microfluidic flow-focusing device that enables one-step generation of microcapsules with an alginate hydrogel shell and an aqueous liquid core of cells from two aqueous fluids. Mouse embryonic stem (ES) cells encapsulated in the liquid core are found to survive well (> 92 %). Moreover, ~ 20 ES cells in the core can proliferate to form a single ES cell aggregate in each microcapsule within 7 days while at least a few hundred cells are usually needed by the commonly used hanging-drop method to form an embryoid body (EB) in each hanging drop. Quantitative RT-PCR analyses show significantly higher expression of pluripotency marker genes in the 3D aggregated ES cells compared to the cells under 2D culture. The aggregated ES cells can be efficiently differentiated into beating cardiomyocytes using a small molecule (cardiogenol C) without complex combination of multiple growth factors. Taken together, the novel 3D microfluidic and pre-hatching embryo-like microcapsule systems are of importance to facilitate in vitro culture of pluripotent stem cells for their ever-increasing use in modern cell-based medicine.

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Little is known about central neuron mechanosensation. Gu et al. report that micromechanical stress preferentially induces rapid and reversible varicosity formation in the axons but not the dendrites of hippocampal neurons through activation of mechanosensitive ion channels and microtubule disassembly.

Highly transparent antifogging/anti-icing coatings were developed from amphiphilic block copolymers of polyhedral oligomeric silsesquioxane-poly[2-(dimethylamino)ethyl methacrylate]-block-poly(sulfobetaine methacrylate) (POSS-PDMAEMA-b-PSBMA) with a small amount of ethylene glycol dimethacrylate (EGDMA) via UV-curing. The excellent antifogging properties of the prepared coatings were originated from the hygroscopicity of both PDMAEMA and PSBMA blocks in the semi-interpenetrating polymer network (SIPN) with polymerization of EGDMA and hydrophobic POSS clusters aggregated on the surface. PDMAEMA with a lower critical solution temperature and PSBMA with an upper critical solution temperature in the block copolymers facilitated dispersion and absorption of water molecules into the SIPN coatings, fulfilling the enhanced antifogging function. Analysis of differential scanning calorimetry further confirmed that there was bond water and nonfreezable bond water in the SIPN coatings. The amphiphilic SIPN coatings exhibited the anti-icing ability with a freezing delay time of more than 2 min at -15 °C, owing to the aggregation of hydrophobic POSS groups and the self-lubricating aqueous layer generated by nonfreezable bond water on the surface. The prepared transparent antifogging/anti-icing coatings could have novel potential applications in practice.

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Size controllable SiO2 nanoparticles synthesized by adjusting the hydrolysis–condensation time and the concentration of tetraethyl orthosilicate (TEOS) in ethanol–water solution in the presence of ammonia as a catalyst were encapsulated within resorcinol–formaldehyde polymer microspheres.

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