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Iron is an essential element in the composition of living organisms and plays a crucial role in a wide range of biological activities. The human body primarily obtains essential iron through the consumption of food. Therefore, it is vital for the health of human body to maintain iron homeostasis. The reducing character of the cellular microenvironment enables Fe 2+ to occupy a dominant position within the cell. Hence, there is an urgent need for a simple and sensitive tool that can detect a large amount of Fe 2+ in organisms. In this work, a highly specific fluorescent chemodosimeter NPCO ("NP" represents the naphthalimide fluorophore, and "CO" represents the carbamoyl oxime structure) for the detection of Fe 2+ with excellent sensitivity (LOD = 82 nM) was constructed by incorporating a novel carbamoyl oxime structure as the recognition group. NPCO can be effectively employed for the detection of Fe 2+ in food samples, living cells, and zebrafish. Furthermore, by using soybean sprouts as a model plant, the application of NPCO was expanded to detect Fe 2+ in plants. Therefore, NPCO could be used as an excellent assay tool for detecting Fe 2+ in organisms and is expected to be an important aid in exploring the mechanism of iron regulation.

As a eukaryotic organelle, the Golgi apparatus plays an essential role in various physiological activities such as stress response. The Golgi stress response is an important physiological process of conferring cytoprotection by regulating the synthesis and metabolism of bioactive molecules. Therefore, the development of new suitable in situ analytical techniques for monitoring related small molecular substances in the stress reaction of the Golgi apparatus is very helpful for further study of the regulatory mechanism of the Golgi apparatus. Recent studies have shown that endogenous hydrogen sulfide (H 2 S) also possesses crucial bioregulatory and protective performances in the stress response. Therefore, the high-fidelity in situ mapping of H 2 S production under the Golgi stress response plays an important role not only in revealing cytoprotection functions of H 2 S in the stress response but also in further understanding the regulatory mechanism of the Golgi stress response. In this work, we designed a simple Golgi-targetable H 2 S fluorescent probe ( Gol-H 2 S ) that responds accurately and sensitively to H 2 S in the Golgi apparatus of living cells and zebrafish. On the basis of its superior bioimaging performances, probe Gol-H 2 S was successfully applied to the in situ visualization of H 2 S production under the Golgi stress response elicited by monensin, a specific-Golgi stressor. The related process of the Golgi stress response was validated by stimulation and inhibition experiments. These findings fully demonstrate that H 2 S is an alternative biomarker of the Golgi stress response. Moreover, probe Gol-H 2 S can also be used as a potential tool for disclosing the detailed H 2 S-cytoprotection mechanisms under the regulation of the Golgi stress response in related diseases.

Many viruses often have closely related yet antigenically distinct serotypes. An ideal vaccine against viral infections should induce a multivalent and protective immune response against all serotypes. Inspired by bacterial membrane vesicles (MVs) that carry different protein components, we constructed an agr locus deletion mutant of the Staphylococcus aureus strain (RN4220-Δagr) to reduce potential toxicity. Nanoscale vesicles derived from this strain ( Δagr MVs) carry at least four major components that can deliver heterologous antigens. These components were each fused with a triple FLAG tag, and the tagged proteins could be incorporated into the Δagr MVs. The presentation levels were (3.43 ± 0.73)%, (5.07 ± 0.82)%, (2.64 ± 0.61)%, and (2.89 ± 0.74)% of the total Δagr MV proteins for Mntc-FLAG, PdhB-FLAG, PdhA-FLAG, and Eno-FLAG, respectively. With two DENV envelope E domain III proteins (EDIIIconA and EDIIIconB) as models, the DENV EDIIIconA and EDIIIconB delivered by two staphylococcal components were stably embedded in the Δagr MVs. Administration of such engineered Δagr MVs in mice induced antibodies against all four DENV serotypes. Sera from immunized mice protected Vero cells and suckling mice from a lethal challenge of DENV-2. This study will open up new insights into the preparation of multivalent nanosized viral vaccines against viral infections.

Millimeter-long and well-aligned single-walled carbon nanotubes (SWNTs) have been produced on silica/silicon surfaces using the carbon monoxide chemical vapor deposition (CO-CVD) method. The orientation of the nanotube arrays can be well-controlled by the gas flow during the growth. The majority of the orientated SWNTs are straight and individual. The length of the nanotubes can be >2 mm for a 10 min growth. Furthermore, multidimensional crossed-networks of SWNT can be easily generated by multistep processes. These results present a great opportunity in the controllable production of organized SWNT arrays for large-scale carbon nanotube-based nanodevice fabrication.