Spatially ordered embryo-like structures self-assembled from blastocyst-derived stem cells can be generated to mimic embryogenesis in vitro. However, the assembly system and developmental potential of such structures needs to be further studied. Here, we devise a nonadherent-suspension-shaking system to generate self-assembled embryo-like structures (ETX-embryoids) using mouse embryonic, trophoblast and extra-embryonic endoderm stem cells. When cultured together, the three cell types aggregate and sort into lineage-specific compartments. Signaling among these compartments results in molecular and morphogenic events that closely mimic those observed in wild-type embryos. These ETX-embryoids exhibit lumenogenesis, asymmetric patterns of gene expression for markers of mesoderm and primordial germ cell precursors, and formation of anterior visceral endoderm-like tissues. After transplantation into the pseudopregnant mouse uterus, ETX-embryoids efficiently initiate implantation and trigger the formation of decidual tissues. The ability of the three cell types to self-assemble into an embryo-like structure in vitro provides a powerful model system for studying embryogenesis.

A "smart" core-shell complex is designed to combine a catalytic reaction and automatic separation through remote light control. Here, we present the induced amphiphilic behavior of a surfactant-encapsulated polyoxometalate complex with photoresponsive azobenzene units on the periphery. The reversible phase transfer of the complex shuttle between two incompatible phase termini, driven by a photoisomerization-induced polarity change, further facilitates the separation and recycle of the catalyst.

Constitutional dynamic networks (CDNs) attract interest as signal-triggered reconfigurable systems mimicking natural networks. The application of CDNs to control material properties is, however, a major challenge. Here we report on the design of a CDN consisting of four toehold-modified constituents, two of which act as bidentate units for chain-elongating, while the other two form a tetradentate structure acting as a crosslinking unit. Their hybridization yields a hydrogel of medium stiffness controlled by the balance between bidentate and tetradentate units. Stabilization of the tetradentate constituent by an auxiliary effector up-regulates the crosslinking unit, yielding a high-stiffness hydrogel. Conversely, stabilization of one of the bidentate constituents by an orthogonal effector enriches the chain-elongation units leading to a low-stiffness hydrogel. Using appropriate counter effectors, the hydrogels are reversibly switched across low-, medium- and high-stiffness states. The hydrogels are used to develop self-healing and controlled drug-release matrices and functional materials for operating biocatalytic cascades.

Mimicking complex cellular dynamic chemical networks being up-regulated or down-regulated by external triggers is one of the challenges in systems chemistry. Constitutional dynamic networks (CDNs), composed of exchangeable components that respond to environmental triggers by self-adaption, provide general means to mimic biosystems. We use the structural and functional information encoded in nucleic acid nanostructures to construct effector (input)-triggered constitutional dynamic networks that reveal adaptable catalytic properties. Specifically, CDNs composed of four exchangeable constituents, AA', BA', AB', and BB', are constructed. In the presence of an effector (input) that controls the stability of one of the constituents, the input-guided up-regulation or down-regulation of the CDN's constituents proceeds. As effectors we apply the fuel-strand stabilization of one of the CDN constituents by the formation of the T-A·T triplex structure, or by the K-ion-induced stabilization of one of the CDN constituents, via the formation of a K-ion-stabilized G-quadruplex. Energetic stabilization of one of the CDN constituents leads to a new dynamically adapted network composed of up-regulated and down-regulated constituents. By applying counter triggers to the effector units, e.g., an antifuel strand or 18-crown-6-ether, reconfiguration to the original CDNs is demonstrated. The performance of the CDNs is followed by the catalytic activities of the constituents and by complementary quantitative gel electrophoresis experiments. The orthogonal triggered and switchable operation of the CDNs is highlighted.

Age ≥ 70 years was an independent prognostic factor for gastric cancer after gastrectomy. D1 resection is appropriate and postoperative chemotherapy is possibly unnecessary for elderly patients with gastric cancer.