Porous scaffolds consisting of bioactive inorganic nanoparticles and biodegradable polymers have gained much interest in bone tissue engineering. We report here a facile approach to fabricating poly(l-lactic acid)-grafted hydroxyapatite (g-HAp)/poly(lactide-co-glycolide) (PLGA) nanocomposite (NC) porous scaffolds by solvent evaporation of Pickering high internal phase emulsion (HIPE) templates, where g-HAp nanoparticles act as particulate stabilizers. The resultant porous scaffolds exhibit an open and rough pore structure. The pore structure and mechanical properties of the scaffolds can be tuned readily by varying the g-HAp nanoparticle concentration and internal phase volume fraction of the emulsion templates. With increasing the g-HAp concentration or decreasing the internal phase volume fraction, the pore size and the porosity decrease, while the Young's modulus and the compressive stress enhance. Moreover, the in vitro mineralization tests show that the bioactivity of the scaffolds increases with increasing the g-HAp concentration. Furthermore, the anti-inflammatory drug ibuprofen (IBU) is loaded into the scaffolds, and the drug release studies indicate that the loaded-IBU exhibits a sustained release profile. Finally, in vitro cell culture assays prove that the scaffolds are biocompatible because of supporting adhesion, spreading, and proliferation of mouse bone mesenchymal stem cells. All the results indicate that the solvent evaporation based on Pickering HIPE templates is a promising alternative method to fabricate NC porous scaffolds for potential bone tissue engineering applications.

ARTICLE This journal isMultilayer composite microcapsules, richly and efficiently loaded with healing reagents (Isophorone diisocyanate, IPDI), are prepared based on lignin nanoparticle-stabilized oil-in-water (O/W) Pickering emulsion templates. The size control of the microcapsules is conducted by varying the lignin content and oil-water volume ratio in Pickering emulsions. With scanning electron microscope (SEM) and optical microscope (OM), the resulting microcapsules show spherical shape, ideal structure of rough outer surface and smooth inner surface, shell thickness of 4.5 m and mean diameter of 40-117 m. Fourier transform infrared spectra (FTIR) and Thermal gravimetric analysis (TGA) indicate extraordinary characteristics of the capsules: core fractions of 81.1 wt.%, excellent thermal stability with initial evaporating temperature of IPDI elevated for 72 °C, firm durability among aqueous solution-submersion and air-exposure with mass loss about 9.7 wt.% after four days submersion or two weeks exposure. Furthermore, the microcapsules are embedded into epoxy coatings for applying this technology into anticorrosive polymer coatings. Investigated by brine-submersion corrosion-accelerating test, the selfhealing microcapsules-incorporated epoxy coatings on steel plates demonstrate good dispersibility of capsules in coatings and favourable anticorrosive effects.

The introduction of nanomaterials to hydrogels is an effective way to improve the mechanical properties of hydrogels. Herein, carbon nanodot (C‐dot) as a new‐found excellent nanomaterial is first added to polyvinyl alcohol (PVA) hydrogel to prepare PVA/C‐dot hydrogel by freeze–thaw method. The appropriate size and plenty of surface functional groups make C‐dot an ideal nucleating agent for PVA crystallization, which leads to form a denser and more uniform cross‐linked network in PVA hydrogel, and in turn enhance the mechanical properties of PVA hydrogel. Compared to pure PVA hydrogel, about a 46.4% increase of tensile strength and 18.5% increase of elongation at break are achieved when the content of C‐dot in PVA/C‐dot hydrogel is 2 wt%, suggesting that C‐dot can effectively improve the mechanical properties of PVA hydrogel. Besides, C‐dot can endow PVA hydrogel with some new properties, such as fluorescence and reducibility. Herein, Ag nanoparticles are simply introduced and uniformly dispersed in PVA hydrogels with the help of reducibility of C‐dot, which can greatly enhance the antibacterial activity of PVA/C‐dot hydrogels, and enlarge their application potential in medical field.

A unique one-dimensional (1D) legume-like structure of cobalt nanoparticles was prepared by a simple magnetic-field-induced assembly approach with the assistance of polyvinylpyrrolidone (PVP). In each ‘legume’, cobalt nanoparticles were regularly aligned along the lines of magnetic force in a row with visible spacing between adjacent nanoparticles and permanently linked with PVP molecule layers in order to maintain the ordered shape after the removal of the external magnetic field. Magnetic measurement showed that these legume-like structures were superparamagnetic at room temperature, while appearing somewhat ferromagnetic at 10 K, obviously indicating magnetostatic coupling between nanoparticles at low temperature. This novel legume-like structure would provide a new model system for the study of magnetization properties of one-dimensionally ordered magnetic nanostructures.

Superior mechanical, recoverable, and swelling properties are important for the application practice of hydrogel. However, most of the hydrogels do not possess those three features at the same time. Herein, we have prepared a novel low chemical cross-linked polyacrylamide (PAM)/carbon nanodot (C-dot) hydrogel by introducing the C-dot into low chemically cross-linked PAM network. C-dot acts as both a physical cross-linker and lubricant in the low chemical cross-linked PAM network, and the synergistic effect between C-dot and PAM chains endows the hydrogel with extraordinary mechanical, recoverable, and swelling properties. The as-prepared hydrogel can be stretched over 3700% with fracture strength as high as 166 kPa, and it can keep high recoverability even when it is stretched up to 500% (more than 97% recovery ratio). Furthermore, the highest swelling ratio of the hydrogel is up to 235 times, which is much higher than that of the conventional PAM hydrogel. Moreover, even in the swelling equilibrium state, the hydrogel can be stretched up to 650% and almost completely recover once the stress is removed. The hydrogel with such an excellent mechanical property in both as-prepared and swollen states is barely reported and can greatly extend its potential application in biomedical fields.