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Theranostic nanoprobes can potentially integrate imaging and therapeutic capabilities into a single platform, offering a new personalized cancer diagnostic tool. However, there is a growing concern that their clinical application is not safe, particularly due to metal-containing elements, such as the gadolinium used in magnetic resonance imaging (MRI). We demonstrate for the first time that the photothermal melting of the DNA duplex helix was a reliable and versatile strategy that enables the on-demand degradation of the gadolinium-containing MRI reporter gene from polydopamine (PDA)-based theranostic nanoprobes. The combination of chemotherapy (doxorubicin) and photothermal therapy, which leads to the enhanced anti-tumor effect. In vivo MRI tracking reveals that renal filtration was able to rapidly clear the free gadolinium-containing MRI reporter from the mice body. This results in a decrease in the long-term toxic effect of theranostic MRI nanoprobes. Our findings may pave the way to address toxicity issues of the theranostic nanoprobes.

Carbon nanotubes-supported non-precious metal nanoparticles emerge as promising catalyst candidate for fuel cell. Although it is well known that carbon nanotubes can influence the catalytic activity of transition metal nanoparticles, insights into whether the unrolling of carbon nanotubes can be exploited to enhance the oxygen reduction performance are lacking. Herein we demonstrate the transformation from FeS/Fe3C nanoparticles coupled S, N dual doped carbon nanotubes (FeS/Fe3C@S, N-C) to nanosheets can yield the improved oxygen reduction performance. Under a glucose protective strategy, the walls of FeS/Fe3C@S, N-C nanotubes were unrolled and extended, creating FeS/Fe3C nanoparticles coupled S, N dual doped carbon nanosheets (FeS/Fe3C@S, N-C g(50)) with larger surface area and higher doping level, which allowed for the exposure of sufficient accessible active sites. Consequently, FeS/Fe3C@S,N-C g(50) exhibited an onset potential of 0.938 V, together with low peroxide yield, good selectivity and durability. Our investigations showed that the carbon matrix with an opened structure and abundant accessible active sites is critical to the electrocatalysts. Furthermore, the synergetic effect of the S, N dual doped carbon nanosheets and FeS/Fe3C nanoparticles contributed to the enhanced oxygen reduction activity. We expect the presented structure–activity relationship can provide guidance for future design of advanced electrocatalysts.

Titanium nitride, an alternative plasmonic material to gold with unique physiochemical properties, has been widely used in microelectronics, biomedical devices and food-contact applications. However, its potential application in the area of biomedicine has not been effectively explored. With the spectral match of their plasmon resonance band and the biological transparency window as well as good biocompatibility, titanium nitride nanoparticles (TiN NPs) are promising photoabsorbing agents for photothermal therapy (PTT) and photoacoustic imaging. Nevertheless, the photothermal performance of TiN NPs has not been investigated until now. Here, we presented the investigation of employing TiN NPs as photoabsorbing agents for in vivo photoacoustic tomography (PAT) imaging-guided photothermal cancer therapy. Our experimental results showed that TiN NPs could strongly absorb the NIR light and provided up to 48% photothermal conversion efficiency. After PEGylation, the resultant nanoparticles demonstrated improved physiological stability and extensive blood retention. Following intravenously administration, they could simultaneously enhance the photoacoustic signals of the tumor region and destroy tumors in the tumor-bearing mouse model by taking advantage of the photothermal effect of the TiN NPs. Our findings highlighted the great potential of plasmonic TiN NPs in detection and treatment of cancer.

Nuclear power plants are expanding rapidly around the world to meet the growing energy demands. The effective capture of volatile radioiodine is an important area of research that is associated with the reprocessing of used nuclear fuel. However, the construction of high-performance adsorbents depends largely on an in-depth comprehension of the underlying binding mechanism at the gas-solid interface. Recently, a growing number of studies have demonstrated the pivotal role of optimizing the interface properties and binding sites, thereby regulating the interaction between the host (adsorbent) and guest (iodine) molecules. In this review, we first introduce the present understanding of the main mechanism for removing volatile radioiodine, and give more detailed descriptions of the capture pathways of specified adsorbents. Then, we discuss nanointerface engineering in materials, which have been conducted in various studies, and review the result of recent studies. Finally, nanointerface engineering based on the adjustment of host-guest interactions are summarized, and future research directions are presented.

In this work, a novel multiplex electrochemiluminescence (ECL) DNA sensor has been developed for determination of hepatitis B virus (HBV) and hepatitis C virus (HCV) based on multicolor CdTe quantum dots (CdTe QDs) and Au nanoparticles (Au NPs). The electrochemically synthesized graphene nanosheets (GNs) were selected as conducting bridge to anchor CdTe QDs551-capture DNA(HBV) and CdTe QDs607-capture DNA(HCV) on the glassy carbon electrode (GCE). Then, different concentrations of target DNA(HBV) and target DNA(HCV) were introduced to hybrid with complementary CdTe QDs-capture DNA. Au NPs-probe DNA(HBV) and Au NPs-probe DNA(HCV) were modified to the above composite film via hybrid with the unreacted complementary CdTe QDs-capture DNA. Au NPs could quench the electrochemiluminescence (ECL) intensity of CdTe QDs due to the inner filter effect. Therefore, the determination of target DNA(HBV) and target DNA(HCV) could be achieved by monitoring the ECL DNA sensor based on Au NPs-probe DNA/target DNA/CdTe QDs-capture DNA/GNs/GCE composite film. Under the optimum conditions, the ECL intensity of CdTe QDs551 and CdTe QDs607 and the concentration of target DNA(HBV) and target DNA(HCV) have good linear relationship in the range of 0.0005-0.5 nmol L(-1) and 0.001-1.0 nmol L(-1) respectively, and the limit of detection were 0.082 pmol L(-1) and 0.34 pmol L(-1) respectively (S/N = 3). The DNA sensor showed good sensitivity, selectivity, reproducibility and acceptable stability. The proposed DNA sensor has been employed for the determination of target DNA(HBV) and target DNA(HCV) in human serum samples with satisfactory results.

Despite the progress in the design and synthesis of theranostic agents, limitations on efficiency and safety offer significant room for improvement in these agents. Inspired by the natural binding ability of polydopamine nanospheres (PDAs) with iron ion, a simple and versatile synthesis strategy is developed to prepare biodegradable coordination polymer (CP) encapsulated PDAs nanocomplex (PDAs@CPx, x = 3, 6, 9). We found that the PDAs@CP3 can serve as a T1/T2 dual mode contrast agent (DMCA) for magnetic resonance imaging (MRI), which possesses high longitudinal (r1 = 7.524 mM(-1) s(-1)) and transverse (r2 = 45.92 mM(-1) s(-1)) relaxivities. In this system, benefitting from the high photothermal conversion efficiency derived from PDAs, DOX loaded PDAs@CP3 nanocomplex is able to not only destroy the tumor directly by heat, but also stimulate the chemotherapy by enabling NIR-responsive on demand delivery of DOX. To the best of our knowledge, this is the first example exploring the potential of PDAs@CPx nanocomplex for T1/T2 dual mode MRI-guided chemo-photothermal synergistic therapy. This work extends the currently available theranostic agents, and opens up new avenues to rationally design the high-performance T1/T2 DMCA.

The serious health risk of sunscreens is mainly attributed to the self-induced damages. Not merely spontaneously generate deleterious reactive oxygen species (ROS), sunscreens also can penetrate through the skin and enter the body, resulting in a series of detrimental effects. Although numerous attempts have been made to remove these risks, safety hazards from sunscreens have not been fully overcome yet. Mainly because almost all of the currently proposed strategies are limited to address only one issue-either the restriction of self-generated ROS or improvement of retention. Here, we integrate the two issues as a whole, enabling us to develop a novel dual-protective sunscreen nanoparticles (DSNPs) to combat the above inherent defects of sunscreens at the same time. The antioxidants-wrapped sunscreen cores are encapsulated into aldehyde-functionalized outer silica shell, which can not only drastically scavenge self-generated ROS, but also achieve strong attachment with the skin surface. We validate the ultra-high efficiency of this dual-protective strategy through a series of in vitro and in vivo experimentations. Specifically, the DSNPs achieve the most efficient scavenging efficiencies of self-generated ROS and are efficiently prevented from entering the body. This dual-protective sunscreen opens a new dimension for the rational design of next-generation sunscreen with minimal side effects.

Enhancing the catalytic activity of non-precious metal catalysts (NPMCs) for oxygen reduction reaction (ORR) requires determination of active centers and a better understanding of the structure–activity relationship. However, key technical challenges in controlling the structural uniformity of NPMCs and maximizing the number of exposed active sites make this goal hard to achieve. Here, inspired by the facile self-assembly strategy for DNA metallization, we have fabricated Co–adenine nanocomposite spheres (Co–A NSs) with uniform structures and well-recognized Co–N4 configuration. Direct pyrolysis of Co–A NSs leads to the formation of monodisperse rambutan-like Co–N/C composites with high porosity and degree of graphitization, as well as homogeneous and high-density Co–N active sites, which endow them with excellent ORR catalytic activity in both base and acid conditions. With Co–N/C as the cathode catalyst, the assembled alkaline direct methanol fuel cell (ADMFC) generates extremely high open-circuit voltage (0.80 V) and unprecedentedly high maximum output power density (40.1 mW cm−2), which is successfully utilized to illuminate a light-emitting diode (LED) lantern. Moreover, the easily controlled structure of Co–N/C catalysts enables us to further reveal their structure–activity relationship, which may provide guidance for future design of advanced electrocatalysts.

We report here the development of Gd-doped ZnO quantum dots (QDs) as dual modal fluorescence and magnetic resonance imaging nanoprobes. They are fabricated in a simple, versatile and environmentally friendly method, not only decreasing the difficulty and complexity, but also avoiding the increase of particle's size brought about by silica coating procedure in the synthesis of nanoprobes reported previously. These nanoprobes, with exceptionally small size and enhanced fluorescence resulting from the Gd doping, can label successfully the HeLa cells in short time and present no evidence of toxicity or adverse affect on cell growth even at the concentration up to 1 mm. These results show that such nanoprobes have low toxicity, especially in comparison with the traditional PEGylated CdSe/ZnS or CdSe/CdS QDs. In MRI studies, they exert strong positive contrast effect with a large longitudinal relaxivity (r(1)) of water proton of 16 mm(-1) s(-1). Their capability of imaging HeLa cells with MRI implies that they have great potential as MRI contrast agents. Combining the high sensitivity of fluorescence imaging with high spatial resolution of MRI, We expect that the as-prepared Gd-doped ZnO QDs can provide a better reliability of the collected data and find promising applications in biological, medical and other fields. (C) 2010 Elsevier Ltd. All rights reserved.

Nitroexplosives, such as 2,4,6-trinitrotoluene (TNT) which is a leading example of nitroaromatic explosives, are causing wide concern. Motivated by the urgent demand for trace analysis of explosives, novel surface-enhanced Raman spectroscopy substrates based upon highly ordered Au nanoparticles have been fabricated by a simple droplet evaporation method. It is noteworthy that an ethylhexadecyldimethyl ammonium bromide bilayer surrounding each individual nanoparticle not only is responsible for these periodic gap structures, but also tends to promote the adsorption of TNT on the composite NPs, thus resulting in a considerable increase of Raman signal. These desirable features endow the resulting SERS substrates with excellent enhancement ability and allow for a label-free detection of common plastic explosive materials even with a concentration as low as 10(-9) M. (C) 2010 Elsevier B.V. All rights reserved.

Organic-inorganic hybrid nanofibers are successfully synthesized by incorporating 3,3 ',5,5 '-tetramethylbenzidine (TMB) and H2PtCl6 at room temperature. The morphology and size can be simply controlled by tuning the molar ratio and initial concentration of reactants. A possible formation mechanism was suggested on the basis of the experimental results. The optical properties were investigated and the as-obtained product displays a strong fluorescence emission at room temperature that may be promising for applications in the fabrication of photoelectric materials. (C) 2008 Elsevier B.V. All rights reserved.

A straightforward combination of the seeding growth method and replacement reaction allowed for the formation of a nanorattle composed of a gold core and Pt/Ag shell. The size, structure, and composition of the Pt/Ag rattle-type nanostructure were confirmed by scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectrometry.

This letter reports a facile and efficient strategy for the designed preparation of highly ordered hollow Ag/TiO2 nanostructure. Different from previous reports, the presently proposed method conveniently combines the long-range ordering porosity and the property of Ag nanoparticles by a general colloidal crystal-templating technique. The sample was characterized by SEM and XRD. The results show that such hollow nanostructured material is composed of anatase TiO2 and metal Ag. The as-prepared sample shows a good photocatalytic activity for photodegradation of methyl orange compared with the reference samples, which was attributed to its long-range ordering porosity and the addition of Ag nanoparticles.