FeP-Based Nanotheranostic Platform for Enhanced Phototherapy/Ferroptosis/Chemodynamic Therapy.

Ferroptosis is an iron-dependent and lipid peroxides (LPO)-overloaded programmed damage cell death, induced by glutathione (GSH) depletion and glutathione peroxide 4 (GPX4) inactivation. However, the inadequacy of endogenous iron and reactive oxygen species (ROS) restricts the efficacy of ferroptosis. To overcome this obstacle, a near-infrared photo-responsive FeP@PEG NPs is fabricated. Exogenous iron pool can enhance the effect of ferroptosis via the depletion of GSH and further regulate GPX4 inactivation. Generation of ·OH derived from the Fenton reaction is proved by increased accumulation of lipid peroxides. The heat generated by photothermal therapy and ROS generated by photodynamic therapy can enhance cell apoptosis under near-infrared (NIR-808 nm) irradiation, as evidenced by mitochondrial dysfunction and further accumulation of lipid peroxide content. FeP@PEG NPs can significantly inhibit the growth of several types of cancer cells in vitro and in vivo, which is validated by theoretical and experimental results. Meanwhile, FeP@PEG NPs show excellent T2-weighted magnetic resonance imaging (MRI) property. In summary, the FeP-based nanotheranostic platform for enhanced phototherapy/ferroptosis/chemodynamic therapy provides a reliable opportunity for clinical cancer theranostics.

Vanadium nitride decorated carbon cloth anode promotes aniline degradation and electricity generation of MFCs by efficiently enriching electroactive bacteria and promoting extracellular electron transfer.

To increase the colonization of electroactive bacteria and accelerate the rate of extracellular electron transfer, a simple coated anode of microbial fuel cell was designed. Here, we took advantage of vanadium nitride (VN) particles to modify the carbon cloth (VN@CC). Compared with bare carbon cloth, the designed VN@CC bioanodes exhibited a larger electrochemically active area, better biocompatibility, and smaller charge transfer impedance. The MFC with VN@CC bioanodes achieved the maximum power density of 3.89 W m-2 and chemical oxygen demand removal rate of 84% when 1000 mg L-1 aniline was degraded, which were about 1.88 and 2.8 times that of CC. The morphology of biofilm and 16s rRNA gene sequence analysis proved that the VN@CC bioanodes facilitated the enrichment of electroactive bacteria (99.02%) and increased the ratio of fast electron transfer in the extracellular electron transfer, thus enhancing the MFC performance of aniline degradation and power output. This work disclosed that it was feasible to increase the overall performance of MFC by enhancing the EET efficiency and presented valuable insights for future work.

Highly Sensitive and Omnidirectionally Stretchable Bioelectrode Arrays for In Vivo Neural Interfacing.

Flexible electrode array, a new-generation neural microelectrode, is a crucial tool for information exchange between living tissues and external electronics. Till date, advances in flexible neural microelectrodes are limited because of their high impedance and poor mechanical consistency at tissue interfaces. Herein, a highly sensitive and omnidirectionally stretchable polymeric electrode array (PEA) is introduced. Micropyramid-nanowire composite structures are constructed to increase the effective surface area of PEA, achieving an exponential reduction in impedance compared with gold (Au) and flat polypyrrole electrodes. Moreover, for the first time, a suspended umbrella structure to enable PEA with omnidirectional stretchability of up to ≈20% is designed. The PEA can withstand 1000 cycles of mechanical loads without decrease in performance. As a proof of concept, PEA is conformally attached to a rat heart and tibialis anterior muscle, and electrophysiological signals (electrocardiogram and electromyogram) of the rat are successfully recorded. This strategy provides a new perspective toward highly sensitive and omnidirectionally stretchable PEA that can facilitate the practical application of neural electrodes.

Metallic zirconium carbide mediated near-infrared driven photocatalysis and photothermal sterilization for multidirectional water purification.

Undoubtedly, taking full advantage of near-infrared light (NIR) for the photocatalytic reaction is a promising way to realize the efficient utilization of solar energy. In this work, zirconium carbide (ZrC) has been exploited as a NIR-driven photoactive substance for the simultaneous photodegradation of organic pollutants and photothermal sterilization of Escherichia coli (E. coli). The metallic nature and NIR-responsive localized surface plasmon resonance (LSPR) behaviors of ZrC are revealed by both experimental evidence and density function theory (DFT) calculations. ZrC exhibits extremely wide spectral absorbance, excellent NIR-triggered photosensitive effect and photothermal conversion efficiency. Activation kinetics was performed with DFT to investigate the activation process of O2 to •O2-. In addition, a possible NIR-mediated photocatalytic mechanism of ZrC was proposed on the basis of above DFT simulation and radical scavenging experiments. Metallic ZrC with NIR-responsive activity provides a new perspective for designing full-spectrum-driven photocatalysts.

Low-work-function LaB6 for realizing photodynamic-enhanced photothermal therapy.

There is great potential for photodynamic therapy (PDT)-enhanced photothermal therapy (PTT) to be used for tumor therapy, especially for the single material-mediated process that could greatly simplify the experimental arrangements. This study presents a new cancer phototherapeutic agent consisting of low-work-function lanthanum hexaboride particles, which are excellent light absorbers in the near-infrared (NIR) region. The photothermal effect and reactive oxygen species production were realized by LaB6 under NIR light irradiation. Theoretical calculations based on density functional theory confirmed that the strong NIR light absorption by LaB6 was attributed to the local plasmonic resonance effect and the excellent photodynamic effect derived from the low work function. In vivo treatment of HepG2 tumor-bearing mice revealed that LaB6-mediated phototherapy resulted in excellent tumor inhibitory effects, and no adverse effects on mice were observed. These results indicate that LaB6 is a promising phototherapeutic agent for cancer synergetic phototherapy.

Phototherapy together with it triggered immunological response for Anti-HPV treatment of oropharyngeal cancer: Removing tumor and pathogenic virus simultaneously.

Oropharyngeal squamous cell carcinoma (OPSCC) is one of most common cancers that often brings lots of inconvenience to the patient in swallowing and phonation even after the operation. Moreover, OPSCC is typically as nodal metastases and high recurrence rate due to the high-risk human papillomavirus (HPV) infection for 90% of patients. Obviously, completely curing OPSCC requires simultaneous removal of solid tumor and related pathogenic virus, which is very indispensable but never be realized by any kind of clinical therapy up to now. In this work, we selected the ZrC nanoparticles as difunctional photoactive substance for synchronous generation of hyperthermia and reactive oxygen species (ROS) under NIR excitation. The resultant synergistic photothermal and photodynamic treatment outcome contributed to an excellent anti-tumor effect. The phototherapy of this work was found not only to be able to damage cancer cells directly, but also could trigger the host immunity for further tumor removal and desirable HPV inactivation. An immunologic mechanism of this work was reasonable proposed by monitoring level of shock protein (HSP), calreticulin (CRT), T lymphocytes and dendritic cells (DCs) and immune check point of B7H3, B7H4 and PD-L1 post phototherapy. It was found that tumor-associated antigens of CRT ("eat-me" signal), HSPs and cell debris were released as cancer cell damage, and then the adaptive immune system and the congenital immunity were triggered to activate DCs maturity, antigen presentation to T cells, proliferation of CD4+ and CD8+ T cells, recruiting macrophages and NK cells and so forth immune responses. Being the first example of using phototherapy for virus-related cancer study, this work opens the door for photo-immunotherapy.

Plasmonic Enhanced Reactive Oxygen Species Activation on Low-Work-Function Tungsten Nitride for Direct Near-Infrared Driven Photocatalysis.

Realizing near-infrared (NIR) driven photocatalytic reaction is one of the promising strategies to promote the solar energy utilization and photocatalytic efficiencies. However, effective reactive oxygen species (ROS) activation under NIR irradiation remains to be great challenge for nearly all previously reported photocatalysts. Herein, the cubic-phase tungsten nitride (WN) with strong plasmonic NIR absorption and low-work function (≈3.59 eV) is proved to be able to mediate direct ROS activation by both of experimental observation and theoretical simulation. The cubic WN nanocubes (NCs) are synthesized via the hydrothermal-ammonia nitridation process and its NIR-driven photocatalytic properties, including photocatalytic degradation, hydroxylation, and de-esterification, are reported for the first time in this work. The 3D finite element simulation results demonstrate the size dependent and wavelength tuned plasmonic NIR absorption of the WN NCs. The NIR-driven photocatalytic mechanism of WN NCs is proposed based on density functional theory (DFT) calculated electronic structure and facet dependent O2 (or H2 O) molecular activation, radicals scavenging test, spin trapped electron paramagnetic resonance measurements, and ultraviolet photoelectronic spectrum (UPS). Overall, the results in this work pave a way for the application of low-work-function materials as highly reactive NIR photocatalyst.

Electronic coupling between molybdenum disulfide and gold nanoparticles to enhance the peroxidase activity for the colorimetric immunoassays of hydrogen peroxide and cancer cells.

Peroxidase nanoenzymes exhibit a specific affinity toward substrates, thereby demonstrating application potential for realizing the colorimetric immunoassays of hydrogen peroxide (H2O2), which can be further used as a probe for imaging cancer cells. To enhance the intrinsic peroxidase activity of molybdenum sulfide (MoS2) nanomaterials, gold (Au) nanoparticles with an average diameter of approximately 2.1 nm were modified on a MoS2/carbon surface (denoted as MoS2/C-Au600) via ascorbic acid reduction. MoS2/C-Au600 can oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to generate a blue oxidation product in the presence of H2O2; this product exhibits peroxidase-like activities, superior to those of most existing MoS2-based nanoenzymes. Furthermore, MoS2/C-Au600 exhibits a high detection capability for H2O2 in the range of 1 × 10-5 to 2 × 10-4 mol/L (R2 = 0.99), and the lowest detection limit is 1.82 µmol/L in a sodium acetate and acetic acid buffer solution. Steady state kinetics studies indicate that the catalytic mechanism is consistent with the ping-pong mechanism. Given its strong absorption peak at 652 nm in the visible region, MoS2/C-Au600 can be used to image cancer cells due to the enhanced permeability and retention effect. Our findings demonstrate that the synergistic electronic coupling between multiple components can enhance the peroxidase activity, which can facilitate the development of an effective, facile, and reliable method to perform colorimetric immunoassays of H2O2 and cancer cells.

Cell-cargo mediated ZrN nanoparticle for the synergetic phototherapy on both of mice and rabbits.

Realization of phototherapy on the big animal modal with orthotopic tumor is of considerable significance in view of its great clinical relevance to the human deep tumor treatment. Herein, near infrared (NIR)-active ZrN nanoparticles were chosen for both of photothermal and photodynamic purposes to achieve the synergetic phototherapy on mice with subcutaneous tumor and even rabbits bearing with orthotopic tumor. Broad and strong photoabsorption, photosensitive ROS generation and photothermal effect of ZrN nanoparticles together made it to be ideal candidate for the effective tumor photoablation. Meanwhile, cell-cargo of macrophage enables targeted delivery of ZrN nanoparticles without influence on its photophysical properties. Resultantly, macrophage loaded ZrN could efficiently mediate synergetic phototherapeutic outcome as proved by complete removal of solid tumor from mice and rabbits. In this work, we also introduced B-mode ultrasonography and contrast-enhanced ultrasound technique for monitoring the evolution process of deep orthotopic tumor on rabbits post-treatment and confirmed the pathological changes of vascular degeneration and liquefaction necrosis post phototherapy.

Targeted photothermal therapy of mice and rabbits realized by macrophage-loaded tungsten carbide.

Although great advances have been made in photothermal therapy, the efforts hitherto have mainly achieved antitumor effects in mice with a subcutaneous tumor model, which is less clinically relevant. Therefore, it is very urgent to make further progress in investigating the possibility of larger animal models with orthotopically xenografted tumors for further clinical trials. Herein, macrophage-loaded tungsten carbide has been employed for the photothermal ablation of orthotopic breast tumors in rabbits in a targetable way. Tungsten carbide as an excellent photoactive material can induce on-site hyperthermia and even reactive oxygen species for tumor destruction; meanwhile, the macrophage is a biocarrier that behaves as a "Trojan horse" for tumor targeting. Both experimental results and theoretical simulations verified the broadband photoabsorption of WC. The WC loaded in the macrophages readily maintains the photothermal and photodynamic effects of the bare WC, while its accumulation at the tumor site is nearly 10 times that of bare WC. As such, the complete removal of solid tumors in rabbits was confirmed with the aid of B-mode ultrasound and contrast-enhanced ultrasound surveillance. Apparently, this work advances photothermal therapy one step further to large animal models with orthotopic tumors.

A near-infrared responsive germanium complex of Ge/GeO2 for targeted tumor phototherapy.

The development of photoactive nanomaterials with high biocompatibility for targeted tumor phototherapy is of great significance for antitumor applications; this study presents a novel phototherapeutic agent, the Ge/GeO2 complex, which shows broad photoabsorption in the near infrared (NIR) region. As a result, it can synchronously produce reactive oxygen species (ROS) and heat under NIR irradiation. After being loaded onto macrophages, Ge/GeO2 could be delivered to tumors in a targeted fashion. Combining the abovementioned merits together, macrophage-loaded Ge/GeO2 realized in vivo synergetic photothermal and photodynamic outcomes to completely remove solid tumors in mice via intravenous administration. In this study, B-ultrasonography was also employed to monitor the tumor evolution after phototherapy, revealing a sequential process of tumor necrosis, liquefaction/softening, and finally disappearance. In addition, Ge/GeO2 proposed in this study shows negligible cytotoxicity and hematotoxicity, especially after being loaded onto macrophages.

Three-dimensional high performance free-standing anode by one-step carbonization of pinecone in microbial fuel cells.

In this paper, the free-standing macroporous carbon anode is prepared by one-step carbonization of pinecone without any further modification. The obtained anode is N, P-codoped porous carbon material, which is beneficial for electrochemical active bacterial adhesion and the fast start-up of cells. Both of the output voltage and long-term operation stability of the obtained anode are higher than that of carbon felt. The charge transfer resistance after biofilm formation is only 1.4 Ω, being 85.1% lower than that of carbon felt anode. 16S rRNA gene sequence analysis shows that Geobacter soli is the main electricigen and its ratio at the obtained anode is much higher than that at carbon felt (77.4% vs 34.0%). The N, P-codoped carbon as the three-dimensional free-standing anode has excellent electrochemical properties and is low cost and easy preparation. Most importantly, it enhances extracellular electron transfer, thus has potential application in microbial fuel cells.

The theranostic nanoagent Mo2C for multi-modal imaging-guided cancer synergistic phototherapy.

Multifunctional theranostic platforms, especially single component-based platforms, enable both cancer treatment and real-time imaging as well as enhance the efficiency of treatment. In this study, 50 nm Mo2C nanospheres were explored as a "one-for-all" theranostic agent. The light-harvesting of Mo2C covered the entire near infrared region, and NIR irradiation concurrently triggered hyperthermia and reactive oxygen species (ROS) production; thus, synergistic outcomes of photothermal and photodynamic therapy could be realized. Both in vitro and in vivo experiments have confirmed the superiority of the synergistic phototherapy in killing cancer cells and removing solid tumors; moreover, Mo2C proposed herein has been proven to be applicable as a photoacoustic imaging and CT imaging contrast agent for in vivo tumor depiction; furthermore, Mo2C demonstrates excellent biocompatibility, showing minimal hematotoxicity and tissue toxicity. A theoretical simulation performed by density functional theory revealed that the metallic character and the interband/intraband transition of Mo2C accounted for its broad photoabsorption. The antitumor mechanism of Mo2C was investigated on a solid tumor by B-mode ultrasonography (US) and magnetic resonance imaging (MRI), revealing a typical liquefactive necrosis process; hence, herein, the dual-imaging guided phototherapy was efficiently mediated by Mo2C.

SnxWO3 as a theranostic platform for realizing multi-imaging-guided photothermal/photodynamic combination therapy.

Precise oncotherapy requires effective cancer treatments that are guided by clinical imaging techniques. One of the most representative cases is multi-imaging-guided phototherapy. This study presents a novel multifunctional theranostic agent of SnxWO3 tungsten bronze, which is an excellent light absorber in the near infrared (NIR) range. Theoretical calculations based on density functional theory confirm that the insertion of donor Sn atoms into orthorhombic WO3 gives rise to the broadband visible-NIR absorption. Accordingly, both the photothermal effect and reactive oxygen species (ROS) production could be realized under NIR light irradiation by SnxWO3 tungsten bronze nanocrystals, thereby triggering the potent in vivo photothermal and photodynamic synergistic therapy. Meanwhile, modified SnxWO3 tungsten bronze has the functions of photoacoustic imaging (PAI), X-ray computed tomography (CT) imaging and near-infrared fluorescence (NIRF) imaging for tumor detection as well. Finally, for investigating the antitumor mechanism of in vivo solid tumors, clinical imaging modalities of B-mode ultrasonography (US) and magnetic resonance imaging (MRI) are employed to monitor the tumor evolution process after the photo-treatment, verifying a typically liquefactive necrosis process. These results indicate that the SnxWO3 tungsten bronze nanostructure is a promising theranostic agent for imaging-guided cancer therapy.

Surface-engineered vanadium nitride nanosheets for an imaging-guided photothermal/photodynamic platform of cancer treatment.

Of the many strategies for precise tumor treatment, near-infrared (NIR) light-activated "one-for-all" theranostic modality with real-time diagnosis and therapy has attracted extensive attention from researchers. Herein, a brand-new theranostic nanoplatform was established on versatile vanadium nitride (VN) nanosheets, which show significant NIR optical absorption, and resultant photothermal effect and reactive oxygen species activity under NIR excitation, thereby realizing the synergistic action of photothermal/photodynamic co-therapy. As expected, systematic in vitro and in vivo antitumor evaluations demonstrated efficient cancer cell killing and solid tumor removal without recurrence. Meanwhile, the surface modification of VN nanosheets with poly(allylamine hydrochloride) and bovine serum albumin enhanced the biocompatibility of VN and made it more suitable for in vivo delivery. Moreover, VN has been ascertained as a potential photoacoustic imaging contrast for in vivo tumor depiction. Thus, this work highlights the potential of VN nanosheets as a single-component theranostic nanoplatform.

Oxygen vacancy induces self-doping effect and metalloid LSPR in non-stoichiometric tungsten suboxide synergistically contributing to the enhanced photoelectrocatalytic performance of WO3-x/TiO2-x heterojunction.

A WO3-x/TiO2-x nanotube array (NTA) heterojunction photoanode was strategically designed to improve photoelectrocatalytic (PEC) performance by establishing a synergistic vacancy-induced self-doping effect and localized surface plasmon resonance (LSPR) effect of metalloid non-stoichiometric tungsten suboxide. The WO3-x/TiO2-x NTA heterojunction photoanode was synthesized through a successive process of anodic oxidation to form TiO2 nanotube arrays, magnetron sputtering to deposit metalloid WO3-x, and post-hydrogen reduction to engender oxygen vacancy in TiO2-x as well as crystallization. On the merits of such a synergistic effect, WO3-x/TiO2-x shows higher light-harvesting ability, stronger photocurrent response, and resultant improved photoelectrocatalytic performance than the contrast of WO3-x/TiO2, WO3/TiO2 and TiO2, confirming the importance of oxygen vacancies in improving PEC performance. Theoretical calculation based on density functional theory was applied to investigate the electronic structural features of samples and reveal how the oxygen vacancy determines the optical property. The carrier density tuning mechanism and charge transfer model were considered to be associated with the synergistic effect of self-doping and metalloid LSPR effect in the WO3-x/TiO2-x NTA.

Highly Efficient, Near-Infrared and Visible Light Modulated Electrochromic Devices Based on Polyoxometalates and W18O49 Nanowires.

Over the past years the performance of electrochromic smart windows with the promising potential for significant energy savings has been progressively improved; however, the electrochromic windows have not yet to come into use at scale mainly because the electrochromic materials suffer from some significant drawbacks such as low coloration efficiency, slow switching time, bad durability and poor functionality. Herein, we fabricate the optically modulated electrochromic smart devices through sequential deposition of the crown-type polyoxometalates, K28Li5H7P8W48O184·92H2O (P8W48), and W18O49 nanowires. Unlike most reported electrochromic smart devices, the resulting P8W48 and W18O49 nanocomposites allow active and selective manipulation of the transmittance of near-infrared (750-1360 nm) and visible light (400-750 nm) by varying the applied potential. Furthermore, thanks to the stable nature of both P8W48 and W18O49 and precise structural control over the nanocomposites, the prepared electrochromic smart devices exhibit high efficiency, quick response and excellent stability.

Experimental and theoretical investigation on photocatalytic activities of 1D Ag/Ag2WO4 nanostructures.

Ag2WO4 is a significant photocatalyst that responds to UV light irradiation only, which greatly hinders it for further practical application for solar light. To address this problem, herein, 1D plasmonic Ag/Ag2WO4 photocatalysts have been fabricated by a successive process including hydrothermal synthesis to obtain Ag2WO4 followed by an additional in situ chemical-reduction process for Ag decoration. Then, the structural features, optical properties, and electronic structures of Ag2WO4 and Ag/Ag2WO4 nanowires were systematically investigated via a combination of theoretical calculations and experimental evidence. The plasmon-enhanced Ag/Ag2WO4 nanowires exhibited higher visible-light-driven photocatalytic activity, which performed a desired photodestruction ratio of 91.2% on methylene blue within 60 min and good stability in five cycles. The Ag decoration greatly facilitates visible-light harvesting and thus promotes photogenerated radical oxidation to dye, which is evidenced by the higher hydroxyl radical level of Ag/Ag2WO4 detected in the ESR test during the photocatalytic process. The theoretical calculation based on density functional theory indicates that Ag nanoparticles formed on the surface of Ag2WO4 could narrow the band gap of Ag2WO4. In addition, the surface plasmon resonance absorption effect and fast charge transfer effect in the metal-semiconductor system contribute to the photocatalytic performance of Ag/Ag2WO4.

Non-stoichiometric MoO3-x quantum dots as a light-harvesting material for interfacial water evaporation.

We herein present oxygen-deficient molybdenum oxide quantum dots (MoO3-x QDs), which possess matching-absorption-spectrum to solar light in both visible and near infrared regions, for proof-of-concept of interfacial water evaporation. Theoretical modeling suggests that the unique optical property of MoO3-x QDs results from oxygen defect level, instead of localized surface plasmon resonance.