Designing nanohesives for rapid, universal, and robust hydrogel adhesion.

Nanoparticles-based glues have recently been shown with substantial potential for hydrogel adhesion. Nevertheless, the transformative advance in hydrogel-based application places great challenges on the rapidity, robustness, and universality of achieving hydrogel adhesion, which are rarely accommodated by existing nanoparticles-based glues. Herein, we design a type of nanohesives based on the modulation of hydrogel mechanics and the surface chemical activation of nanoparticles. The nanohesives can form robust hydrogel adhesion in seconds, to the surface of arbitrary engineering solids and biological tissues without any surface pre-treatments. A representative application of hydrogel machine demonstrates the tough and compliant adhesion between dynamic tissues and sensors via nanohesives, guaranteeing accurate and stable blood flow monitoring in vivo. Combined with their biocompatibility and inherent antimicrobial properties, the nanohesives provide a promising strategy in the field of hydrogel based engineering.

Bioinspired polymeric woods.

Woods provide bioinspiration for engineering materials due to their superior mechanical performance. We demonstrate a novel strategy for large-scale fabrication of a family of bioinspired polymeric woods with similar polyphenol matrix materials, wood-like cellular microstructures, and outstanding comprehensive performance by a self-assembly and thermocuring process of traditional resins. In contrast to natural woods, polymeric woods demonstrate comparable mechanical properties (a compressive yield strength of up to 45 MPa), preferable corrosion resistance to acid with no decrease in mechanical properties, and much better thermal insulation (as low as ~21 mW m-1 K-1) and fire retardancy. These bioinspired polymeric woods even stand out from other engineering materials such as cellular ceramic materials and aerogel-like materials in terms of specific strength and thermal insulation properties. The present strategy provides a new possibility for mass production of a series of high-performance biomimetic engineering materials with hierarchical cellular microstructures and remarkable multifunctionality.

Bioinspired greigite magnetic nanocrystals: chemical synthesis and biomedicine applications.

Large scale greigite with uniform dimensions has stimulated significant demands for applications such as hyperthermia, photovoltaics, medicine and cell separation, etc. However, the inhomogeneity and hydrophobicity for most of the as prepared greigite crystals has limited their applications in biomedicine. Herein, we report a green chemical method utilizing ß-cyclodextrin (ß-CD) and polyethylene glycol (PEG) to synthesize bioinspired greigite (Fe3S4) magnetic nanocrystals (GMNCs) with similar structure and magnetic property of magnetosome in a large scale. ß-CD and PEG is responsible to control the crystal phase and morphology, as well as to bound onto the surface of nanocrystals and form polymer layers. The GMNCs exhibit a transverse relaxivity of 94.8 mM⁻¹ s⁻¹ which is as high as iron oxide nanocrystals, and an entrapment efficiency of 58.7% for magnetic guided delivery of chemotherapeutic drug doxorubicin. Moreover, enhanced chemotherapeutic treatment of mice tumor was obtained via intravenous injection of doxorubicin loaded GMNCs.