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Plasmonic photocatalysts with a core–shell heterostructure were synthesized via electrochemical deposition guided by single particle plasmonic imaging., Plasmonic photocatalysts have opened up a new direction in utilization of visible light and promoting photocatalytic efficiency. An electrochemical deposition method is reported to synthesise metal@semiconductor (M@SC) core–shell nanocrystals. Due to the strong affinity of Au atoms to S2– and Se2– reduced at negative potential, CdS, CdSe and ZnS were selectively deposited on the surface of the Au core to form a uniform shell with a clear metal/semiconductor interface, which conquered the barrier caused by the large lattice mismatch between the two components. Plasmonic effects increased the photocatalytic performance, as well as provided a chance to in situ monitor the surface nucleation and growth. The structure formation process could be observed under dark-field microscopy (DFM) in real-time and precisely controlled via the scattering color, intensity and wavelength. The proof-of-concept strategy combines the electrochemical deposition and plasmonic imaging, which provides a universal approach in controllable synthesis of core–shell heterostructures, and leads to the improvement of plasmonic photocatalysts.

We construct a tumor redox microenvironment responsive core–shell therapeutic nanoagent for multi-mode imaging guided synergistic therapy in vitro and in vivo., Development of tumor microenvironment responsive and modulating theranostic nano-systems is of great importance for specific and efficient cancer therapy. Herein, we report a redox-sensitive nanoagent combining manganese dioxide (MnO2) and gold nanoshell coated silicon nanoparticles for synergistic chemo-photothermal therapy of hypoxia solid tumors. In highly reducing tumor tissues, the outer MnO2 nanosheet with the loaded drug would be dissociated by intracellular glutathione (GSH), resulting in on-demand drug release, as well as generating Mn2+ ions which provided high contrast magnetic resonance imaging (MRI), and fluorescence imaging (FI) in vitro and in vivo. While upon near-infrared (NIR) light irradiation, the gold nanoshell modulated the hypoxic tumor microenvironment via increasing blood flow, achieving enhanced photothermal therapy (PTT) and chemotherapy. After tail vein injection into tumor-bearing mice and monitoring in real time, the intelligent redox-activated nanoagent exhibited high tumor accumulation and powerful synergistic chemo-photothermal therapy efficiency. The proposed work developed a noninvasive strategy to modulate the tumor microenvironment and enhance the anticancer therapeutic effect. We believe that this single nano-platform exhibits promising potential as a comprehensive theranostic agent to enhance the efficacies of synergistic cancer therapy.

A fluorescent τ-probe was demonstrated to quantitate ultra-trace endogenous hydrogen sulfide (H2Sn) within cells and zebrafish through changes of fluorescence lifetime., Hydrogen sulfide (H2S) has been recognized as an important endogenous gasotransmitter associated with biological signaling transduction. However, recent biological studies implied that the H2S-related cellular signaling might actually be mediated by hydrogen polysulfides (H2Sn, n > 1), not H2S itself. Unraveling such a mystery strongly demanded the quantification of endogenous H2Sn in living systems. However, endogenous H2Sn has been undetectable thus far, due to its extremely low concentration within cells. Herein, we demonstrated a strategy to detect ultra-trace endogenous H2Snvia a fluorescent τ-probe, through changes of fluorescence lifetime instead of fluorescence intensity. This τ-probe exhibited an ultrasensitive response to H2Sn, bringing about the lowest value of the detection limit (2 nM) and a lower limit of quantification (10 nM) to date. With such merits, we quantified and mapped endogenous H2Sn within cells and zebrafish. The quantitative information about endogenous H2Sn in cells and in vivo may have a significant implication for future research on the role of H2Sn in biology. The methodology of the τ-probe established here might provide a general insight into the design and application of any fluorescent probes, beyond the limit of utilizing fluorescence intensity.

Plasmon-enhanced Raman spectroscopic metrics were developed for in situ quantitative and dynamic assays of viable, apoptotic and necrotic cells., Apoptosis and necrosis are distinct cell death processes related to many cellular pathways. In situ, quantitatively and dynamically monitoring such processes may provide vitally important information for cell studies. However, such a method still remains elusive, even though current immunochemical methodologies have developed extremely valuable tools. Herein, we demonstrate Raman spectroscopic metrics for validating and quantifying apoptotic and necrotic cells based on their distinct molecular vibrational fingerprints. It not only allows us to quantify apoptotic and necrotic cell populations in situ in adherent cell samples, but also to be capable of continuously monitoring the dynamical processes of apoptosis and necrosis at the same time in one sample. This method provides comparable results with the “gold standard” of flow cytometry, moreover, with several incomparable advantages. Our work offers a powerful new tool for cell apoptosis and necrosis assays and is expected to become a benchmark technology in biological and medical studies.

We construct a LSPR sensor by invisible oriented probes with zero background for genetic material sensitive detection in living cells., Due to the complexity of biological systems and the ultralow concentration of analytes, improving the signal-to-noise ratio and lowering the limit of detection to allow highly sensitive detection is key to biomolecule analysis, especially intracellular analysis. Here, we present a method for highly sensitive imaging of mRNA in living cells by using novel invisible oriented probes to construct a turn-on signal generation mechanism from zero background. Two DNA probes (S1 and S2) are asymmetrically modified on two small gold nanoparticles (AuNPs) with a diameter of 20 nm. The hybridization of the two DNA probes with a single target mRNA leads to the formation of an AuNP dimer which shows a prominent plasmonic coupling effect. It generates a strong scattering signal from zero-background under a dark-field spectral analysis system. The unique design of the oriented assembly dimer has the ability to easily discriminate the target signal from the inherent cellular background noise in intracellular detection, thus making this approach a valuable technique for imaging single survivin mRNA and monitoring the distribution of survivin mRNA in tumor cells.

A nanohybrid was employed for fingerprint imaging that was capable of simultaneous identification of individuals and TNT visualization in a “traffic-light” manner., Fingerprints are a unique characteristic of an individual. Recently, it has been realized that fingerprints carry more information about individuals than just their identity, for example, they may identify potential addicts and terrorists carrying explosives. Therefore, the development of imaging moieties capable of both fingerprint staining and drug/explosive visualization is of significant importance for forensic chemistry. Here we developed a nanohybrid comprising green- and red-emitting QDs for simultaneous fingerprint imaging and TNT visualization in fingerprints. The red-emitting Cu-doped ZnCdS (Cu–ZnCdS) QDs were embedded into silica nanoparticles and the green-emitting ZnCdS QDs were anchored onto the surface of the silica nanoparticles and further functionalized with polyallylamine (PAA). Both components of the nanohybrid, i.e., the PAA-functionalized green QDs and red QD-doped silica nanoparticles, could be explored for fingerprint imaging. Due to the formation of a Meisenheimer complex between TNT and PAA, the green-emitting QDs could be quenched by TNT, meanwhile the red-emitting QDs were inert. Therefore, the nanohybrid exhibited a traffic light-type fluorescence color change (green-yellow-red) to TNT concentration in the range of 40–400 μM. This method is promising for potential applications in security-screening needs in public areas such as airports and train stations.