The recently emerged photosynthetic biohybrid systems (PBSs) integrate the advantages of the light‐harvesting ability of semiconductors and the catalytic power of biological metabolism. Herein, negatively charged iodine‐doped hydrothermally carbonized carbon (I‐HTCC) is interfaced with surface modified Escherichia coli cells through a facile “add‐on” mode via electrostatic interactions. As a result of the photoexcited electrons, the self‐assembled I‐HTCC@E. coli biohybrid shows enhanced hydrogen production efficiency with a quantum efficiency of 9.11% under irradiation. The transduction of photoelectrons from I‐HTCC to cells is the rate‐limiting step for H2 production and is delivered through both direct injection and the NADH/NAD+‐mediated pathways. The injected photoelectrons fine‐tune the H2 production through the formate and NADH pathways in a subtle manner. The excellent biocompatibility and photostability of the I‐HTCC@E. coli biohybrid demonstrate its potential real‐world application under sunlight. In addition, the proposed “add‐on” mode is extended to a series of negatively charged common carbon‐based materials with different levels of promotion effects compared with that of pure bacterial cultures. This facile and effective mode provides an insight into the rational design of the whole‐cell PBSs with various semiconductors for H2 production.

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Nitrification inhibitors (NIs) 3,4-dimethylpyrazole phosphate (DMPP) and dicyandiamide (DCD) have been used extensively to improve nitrogen fertilizer utilization in farmland. However, their comparative effects on ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in agricultural soils are still unclear. Here, we compared the impacts of these two inhibitors on soil nitrification, AOA and AOB abundance as well as their community structure in a vegetable soil by using real-time PCR and terminal restriction fragment length polymorphism (T-RFLP). Our results showed that urea application significantly increased the net nitrification rates, but were significantly inhibited by both NIs, and the inhibitory effect of DMPP was significantly greater than that of DCD. AOB growth was more greatly inhibited by DMPP than by DCD, and the net nitrification rate was significantly related to AOB abundance, but not to AOA abundance. Application of urea and NIs to soil did not change the diversity of the AOA community, with the T-RFs remaining in proportions that were similar to control soils, while the community structure of AOB exhibited obvious shifts within all different treatments compared to the control. Phylogenetic analysis showed that all AOA sequences fell within group 1.1a and group 1.1b, and the AOB community consisted of Nitrosospira cluster 3, cluster 0, and unidentified species. These results suggest that DMPP exhibited a stronger inhibitory effect on nitrification than DCD by inhibiting AOB rather than AOA.

Transendothelial migration of cancer cells is a critical stage in cancer, including breast cancer, as the migrating cells are generally believed to be highly metastatic. However, it is still challenging for many existing platforms to achieve a fully covering endothelium and to ensure transendothelial migration capability of the extracted cancer cells for analyses with high specificity. Here, we report a microfluidic device containing multiple independent cell collection microchambers underneath an embedded endothelium such that the transendothelial-migrated cells can be selectively collected from only the microchambers with full coverage of an endothelial layer. In this work, we first optimize the pore size of a microfabricated supporting membrane for the endothelium formation. We quantify transendothelial migration rates of a malignant human breast cell type (MDA-MB-231) under different shear stress levels. We investigate characteristics of the migrating cells including morphology, cytoskeletal structures, and migration (speed and persistence). Further implementation of this endothelium-embedded microfluidic device can provide important insights into migration and intracellular characteristics related to cancer metastasis and strategies for effective cancer therapy.

The propulsive efficiency and biodegradability of wireless microrobots play a significant role in facilitating promising biomedical applications. Mimicking biological matters is a promising way to improve the performance of microrobots. Among diverse locomotion strategies, undulatory propulsion shows remarkable efficiency and agility. This work proposes a novel magnetically powered and hydrogel-based biodegradable microswimmer. The microswimmer is fabricated integrally by 3D laser lithography based on two-photon polymerization from a biodegradable material and has a total length of 200 μm and a diameter of 8 μm. The designed microswimmer incorporates a novel design utilizing four rigid segments, each of which is connected to the succeeding segment by spring to achieve undulation, improving structural integrity as well as simplifying the fabrication process. Under an external oscillating magnetic field, the microswimmer with multiple rigid segments connected by flexible spring can achieve undulatory locomotion and move forward along with the directions guided by the external magnetic field in the low Reynolds number (Re) regime. In addition, experiments demonstrated that the microswimmer can be degraded successfully, which allows it to be safely applied in real-time in vivo environments. This design has great potential in future in vivo applications such as precision medicine, drug delivery, and diagnosis.

Mutualistic interactions with arbuscular mycorrhizal fungi (AMF) greatly affect the outcome of plant-plant competition, especially for invasive plants competing against native plants. We examined the effects of AMF on the competition between invasive Asteraceae plants and the phylogenetically related native plants.We compared the performance of seven invasive Asteraceae plants from different genera with that of their phylogenetically related native counterparts in response to AMF in monocultures and mixed cultures. We investigated how interactions with AMF impact the competition between Asteraceae relatives.Total biomass increased with AMF colonization in both invasive and native plants. Arbuscular mycorrhizal fungi improved the competitiveness of invasive plants, but decreased that of native plants. Competition increased the shoot nitrogen, phosphorus and root myristic acid concentrations and relative expression of fatty acid transporter genes (RiFAT1 and RiFAT2) in AMF-colonized invasive plants, but decreased those in AMF-colonized native plants. Structural equation models indicated that the presence of AMF increased the uptake of phosphorus, but not nitrogen, by invasive plants, which probably provided more myristic acids to symbiotic AMF in return.These results suggest that invasive Asteraceae plants have greater mutualistic interactions with AMF than their phylogenetically related native counterparts, potentially contributing to invasion success.

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