Biopolymeric hydrogels have been widely used as carriers of therapeutic cells and drugs for biomedical applications. However, most conventional hydrogels cannot be injected after gelation and do not support the infiltration of cells because of the static nature of their network structure. Here, we develop unique cell-infiltratable and injectable (Ci-I) gelatin hydrogels, which are physically cross-linked by weak and highly dynamic host–guest complexations and are further reinforced by limited chemical cross-linking for enhanced stability, and then demonstrate the outstanding properties of these Ci-I gelatin hydrogels. The highly dynamic network of Ci-I hydrogels allows injection of prefabricated hydrogels with encapsulated cells and drugs, thereby simplifying administration during surgery. Furthermore, the reversible nature of the weak host–guest cross-links enables infiltration and migration of external cells into Ci-I gelatin hydrogels, thereby promoting the participation of endogenous cells in the healing process. Our findings show that Ci-I hydrogels can mediate sustained delivery of small hydrophobic molecular drugs (e.g., icaritin) to boost differentiation of stem cells while avoiding the adverse effects (e.g., in treatment of bone necrosis) associated with high drug dosage. The injection of Ci-I hydrogels encapsulating mesenchymal stem cells (MSCs) and drug (icaritin) efficiently prevented the decrease in bone mineral density (BMD) and promoted in situ bone regeneration in an animal model of steroid-associated osteonecrosis (SAON) of the hip by creating the microenvironment favoring the osteogenic differentiation of MSCs, including the recruited endogenous cells. We believe that this is the first demonstration on applying injectable hydrogels as effective carriers of therapeutic cargo for treating dysfunctions in deep and enclosed anatomical sites via a minimally invasive procedure.

Tin selenide (SnSe) is a newly emerging layered material. SnSe with low dimensionality has been reported as an appealing material with a diverse range of applications such as rechargeable lithium-ion batteries, memory switching devices, solar energy conversion, thermoelectric energy conversion, and near-infrared optoelectronic devices. Here we synthesized SnSe ultrathin flakes on SiO2/Si substrates through simple vapor deposition route and investigated its temperature-dependent Raman spectroscopy behavior with 532, 633, and 785 nm excitation wavelengths. It was found that the Ag 2, Ag 3, and B3g modes soften as temperature increases from 98 to 298 K under all wavelengths. Our results revealed anharmonic phonon properties of SnSe, and they will benefit the advanced study of its thermal properties. This approach will also have large application in characterizing the optical, electronic, and thermal properties of other novel layered materials. Moreover, our results can be utilized to measure the temperature of SnSe-based nanodevices without destruction.

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Flexible dielectric materials with high electrical energy densities are of crucial importance in advanced electronics and electric power systems. The conventional methods for fabricating flexible dielectric materials with high electrical energy densities are introducing zero-, one-, and three-dimensional high-k inorganic nanofiller into a dielectric polymer matrix while less twodimensional high-k nanofillers were included. Herein, two-dimensional (2D) high-k titanium dioxide nanosheets prepared by a one-step hydrothermal reaction were utilized to boost the energy storage performance of dielectric polymer nanocomposites. It was found that compared with the polymer matrix the nanocomposites not only exhibit an enhanced dielectric constant but also show suppressed dielectric loss, which is desirable for energy storage applications. The nanocomposite with 5 wt % 2D nanosheets exhibits a superhigh discharged energy density of 13.0 J/cm 3 at 570 MV/m, which is nearly four times greater than that of commercialized biaxially oriented polypropylene (BOPP) (3.6 J/cm 3 at 600 MV/m). In addition, nanocomposites with 5 wt % zero-and one-dimensional (0D and 1D) nanofiller are also fabricated for comparison. Results reveal that discharged energy densities of nanocomposites with 5 wt % 2D nanosheets are 236% and 382% higher than those of nanocomposites with 5 wt % 1D (5.5 J/cm 3 at 400 MV/m) and 0D (3.4 J/cm 3 at 300 MV/m) nanofiller, respectively. Finite element simulation was conducted to study the electric field distribution in nanocomposites with different shapes of nanofillers. Furthermore, the comparison of the current nanocomposites and previous reported nanocomposites with 0D, 1D, and 3D nanofillers shows that the 2D high-k nanofiller exhibited superior potential in advancing the energy storage nature of polymer nanocomposites. This remarkable exhibition of energy storage capability provides new insights into the development of high performance dielectric materials.

This is a repository copy of Using Host-Guest Chemistry to Tune the Kinetics of Morphological Transitions Undertaken by Block Copolymer Vesicles.