This article provides a progress report on the use of galvanic replacement for generating complex hollow nanostructures with tunable and well-controlled properties. We begin with a brief account of the mechanistic understanding of galvanic replacement, specifically focused on its ability to engineer the properties of metal nanostructures in terms of size, composition, structure, shape, and morphology. We then discuss a number of important concepts involved in galvanic replacement, including the facet selectivity involved in the dissolution and deposition of metals, the impacts of alloying and dealloying on the structure and morphology of the final products, and methods for promoting or preventing a galvanic replacement reaction. We also illustrate how the capability of galvanic replacement can be enhanced to fabricate nanomaterials with complex structures and/or compositions by coupling with other processes such as co-reduction and the Kirkendall effect. Finally, we highlight the use of such novel metal nanostructures fabricated via galvanic replacement for applications ranging from catalysis to plasmonics and biomedical research, and conclude with remarks on prospective future directions.

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Incorporating carbon nanodots (CDs) into mesoporous silica framework for extensive biomedicine, especially for the desirable cancer immunotherapy, is considered to be an unexplored challenge. Herein, a hydrogen bond/electrostatic-assisted co-assembly strategy was smartly exploited to uniformly incorporate polymer-coated CDs into ordered framework of mesoporous silica nanoparticles (CD@ MSNs). The obtained CD@MSN was not only biodegradable via the framework-incorporated CD-induced swelling but also capable of gathering dispersive CDs with enhanced photothermal effect and elevated targeting accumulation, which therefore can achieve photothermal imaging-guided photothermal therapy (PTT) in vitro and in vivo. Interestingly, benefiting from the biodegraded debris, it was found that CD@MSN-mediated PTT can synergistically achieve immunemediated inhibition of tumor metastasis via stimulating the proliferation and activation of natural killer cells and macrophages with simultaneously up-regulating the secretion of corresponding cytokines (IFN-γ and Granzyme B). This work proposed an unusual synthesis of biodegradable mesoporous silica and provided an innovative insight into the biodegradable nanoparticlesassociated anticancer immunity.

A new alkaloid, 2-(furan-2-yl)-6-(2S,3S,4-trihydroxybutyl)pyrazine (1), along with 12 known compounds, 2-(furan-2-yl)-5-(2S,3S,4-trihydroxybutyl)pyrazine (2), (S)-4-isobutyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (3), (S)-4-isopropyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (4), (4S)-4-(2-methylbutyl)-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (5), (S)-4-benzyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (6), flazin (7), perlolyrine (8), 1-hydroxy-β-carboline (9), lumichrome (10), 1H-indole-3-carboxaldehyde (11), 2-hydroxy-1-(1H-indol-3-yl)ethanone (12), and 5-(methoxymethyl)-1H-pyrrole-2-carbaldehyde (13), were isolated and identified from the fermentation broth of an endophytic actinomycetes, Jishengella endophytica 161111. The new structure 1 and the absolute configurations of 2–6 were determined by spectroscopic methods, J-based configuration analysis (JBCA) method, lactone sector rule, and electronic circular dichroism (ECD) calculations. Compounds 8–11 were active against the influenza A virus subtype H1N1 with IC50 and selectivity index (SI) values of 38.3(±1.2)/25.0(±3.6)/39.7(±5.6)/45.9(±2.1) μg/mL and 3.0/16.1/3.1/11.4, respectively. The IC50 and SI values of positive control, ribavirin, were 23.1(±1.7) μg/mL and 32.2, respectively. The results showed that compound 9 could be a promising new hit for anti-H1N1 drugs. The absolute configurations of 2–5, 13C nuclear magnetic resonance (NMR) data and the specific rotations of 3–6 were also reported here for the first time.