No abstract

Nanohydroxyapatite (HA) synthesized by biomimetic strategy is a promising nanomaterial as bone substitute due to its physicochemical features similar to those of natural nanocrystal in bone tissue. Inspired by mussel adhesive chemistry, a novel nano-HA was synthesized in our work by employing polydopamine (pDA) as template under weak alkaline condition. Subsequently, the as-prepared pDA-templated HA (tHA) was introduced into polycaprolactone (PCL) matrix via coelectrospinning, and a bioactive tHA/PCL composite nanofiber scaffold was developed targeted at bone regeneration application. Our research showed that tHA reinforced PCL composite nanofibers exhibited favorable cytocompatibility at given concentration of tHA (0-10 w.t%). Compared to pure PCL and traditional nano-HA enriched PCL (HA/PCL) composite nanofibers, enhanced cell adhesion, spreading and proliferation of human mesenchymal stem cells (hMSCs) were observed on tHA/PCL composite nanofibers on account of the contribution of pDA present in tHA. More importantly, tHA nanoparticles exposed on the surface of composite nanofibers could further promote osteogenesis of hMSCs in vitro even in the absence of osteogenesis soluble inducing factors when compared to traditional HA/PCL scaffolds, which was supported by in vivo test as well according to the histological analysis. Overall, our study demonstrated that the developed tHA/PCL composite nanofibers with enhanced cytocompatibility and osteogenic capacity hold great potential as scaffolds for bone tissue engineering.

Bismuth (Bi), as a nontoxic and inexpensive diamagnetic heavy metal, has recently been utilized for the preparation of a variety of nanomaterials, such as nanoparticles, nanowires, nanotubes, nanosheets, etc., with a tunable bandgap, unique structure, excellent physicochemical properties, and compositional features for versatile properties, such as near‐infrared absorbance, high X‐ray attenuation coefficient, excellent photothermal conversion efficiency, and a long circulation half‐life. These features have endowed mono‐elemental Bi nanomaterials with desirable performances for electronics/optoelectronics, energy storage and conversion, catalysis, nonlinear photonics, sensors, biomedical applications, etc. This review summarizes the controlled synthesis of mono‐elemental Bi nanomaterials with different shapes and sizes, highlights the state‐of‐the‐art progress of the desired applications of mono‐elemental Bi nanomaterials, and presents some personal insights on the challenges and future opportunities in this research area. It is hoped that the controllable manipulation techniques of Bi nanomaterials, along with their unique properties, can shed light on the next‐generation devices based on Bi nanostructures and Bi‐related nanomaterials.

Increasing boom in soft electronics field has boosted the development of highly stretchable and environment-adaptable energy storage devices based on hydrogel electrolytes. Development of such soft energy supply devices still...

Ionic conducting eutectogels have attracted enormous attention as an alternative to the conventional temperature-intolerant hydrogels and costly ionic liquid gels in constructing flexible electronic devices. However, current eutectogels prepared via cross-linked polymer or low-molecular-weight gelators suffer from limited stretchability and insufficient surface-adaptive adhesion. Herein, a low-molecular-weight supramolecular network is introduced into a covalent polymer network in a eutectogel architecture, and a novel supramolecularpolymer double-network (SP-DN) strategy is demonstrated to fabricate conductive SP-DN eutectogels with high stretchability (>4000% elongation) and toughness (≈800 J m −2 ), as well as self-healing, self-adhesive and anti-freezing/ anti-drying characteristics. These unique features lead to the successful realization of SP-DN eutectogels in wearable self-adhesive strain sensors, which can conformally deform with the skin and dynamically monitor body movements with high sensitivity and long-term stability over a wide temperature range (−40 to 60 °C). Furthermore, the strain sensors can accurately detect body movements along two opposite directions (bend up or bend down), which are rarely reported in the literature. Distinct from the widely explored polymer double-network (P-DN) hydrogels, the developed SP-DN eutectogel platform is capable of well-regulating molecular-scale noncovalent and covalent interactions, providing a paradigm for the creation of smart soft materials with versatile performance and high environmental adaptability.