Fe,Ni-Based Metal–Organic Frameworks Embedded in Nanoporous Nitrogen-Doped Graphene as a Highly Efficient Electrocatalyst for the Oxygen Evolution Reaction

The quest for economically sustainable electrocatalysts to replace critical materials in anodes for the oxygen evolution reaction (OER) is a key goal in electrochemical conversion technologies, and, in this context, metal–organic frameworks (MOFs) offer great promise as alternative electroactive materials. In this study, a series of nanostructured electrocatalysts was successfully synthesized by growing tailored Ni-Fe-based MOFs on nitrogen-doped graphene, creating composite systems named MIL-NG-n. Their growth was tuned using a molecular modulator, revealing a non-trivial trend of the properties as a function of the modulator quantity. The most active material displayed an excellent OER performance characterized by a potential of 1.47 V (vs. RHE) to reach 10 mA cm−2, a low Tafel slope (42 mV dec−1), and a stability exceeding 18 h in 0.1 M KOH. This outstanding performance was attributed to the synergistic effect between the unique MOF architecture and N-doped graphene, enhancing the amount of active sites and the electron transfer. Compared to a simple mixture of MOFs and N-doped graphene or the deposition of Fe and Ni atoms on the N-doped graphene, these hybrid materials demonstrated a clearly superior OER performance

Photogeneration of Hydrogen: Insights from a Pt(II)-Complex Incorporated into a Covalent Organic Framework

Pt(II)-based molecular catalysts stand as a prototypical system in hydrogen evolution reactions (HER) owing to their consistently elevated activity levels. Their integration into heterogeneous systems thus provides an ideal platform to develop catalytic materials with optimal atom economy. In this work, by rational molecular design, we have synthesized a novel two-dimensional photoactive Covalent Organic Framework (COF), wherein the pore walls host a quinoline-based alpha-diimine ligand serving as a coordination site for anchoring a Pt(II) molecular catalyst. Thorough structural analyses, employing X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DR), coupled with DFT calculations, distinctly confirm the Pt(II) complexation through the coordination site of the alpha-diimine ligand. The Pt(II)-metalated COF exhibits photocatalytic activity with a hydrogen evolution rate reaching up to 1300 mu mol g-1 h-1. Nevertheless, the occurrence of platinum nanoparticles in post-catalysis samples, along with reduced photocatalytic activity in the presence of chloride ions, suggests that Pt(II) anchored into the COF backbone might not be the primary catalytic site.|An innovative photoactive covalent organic framework (COF) with pore walls featuring a quinoline-based alpha-diimine ligand as a coordination site was synthesized for anchoring a Pt(II) molecular catalyst for hydrogen evolution reaction (HER). Extensive characterization, supported by DFT calculations, shows that H2 evolution is likely driven by the platinum nanoparticles generated through the photocatalytic processes, rather than by Pt(II) species. imageLR

Abstract 4154: Large oncosomes derived from the aggressive prostate cancer sub-line, DU145R80, can modify the biological behavior of the parental DU145 cells

Abstract We have recently established a zoledronic acid-resistant prostate cancer cell line, DU145R80,which exhibits higher invasive capability compared to parental DU145 cells, and epithelial-to-mesenchymal transition (EMT)[Milone MR, Cell Death Dis. 2013]. To investigate the mechanism by which the cells become invasive, we compared DU145R80 and DU145 cells by a proteomic approach, unveiling a signaling network that links the interior of the nucleus to changes in cytoskeleton dynamics and to the extracellular matrix, dictating prostate cancer aggressiveness [Milone MR Oncotarget 2014].Cytoskeletal modifications allow cells to gain a more migratory/invasive behavior and to interact with the surrounding microenvironment triggering different kind of biological phenomena, including the formation of large oncosomes (LO), a bioactive class of extracellular vesicles (EVs) [Di Vizio D, Cancer Res. 2009]. In this study, we found a higher amount of spontaneously shed LO along with an increased gelatinase activity from DU145R80 cells compared to the parental counterpart. By applying low speed and discontinuous gradient ultracentrifugation to both DU145 and DU145R80 cell media, we obtained a pure preparation of LO, floating at a 1.15 g/mL density fraction and positive for LO markers such as as Cav-1, Ck18, GAPDH. Moreover, we treated DU145 parental cells with pure preparations of LO from either DU145 or DU145R80 cells and performed an invasion assay, showing that LO from the resistant, aggressive DU145R80 cell line increase the invading ability of DU145. Treatment of DU145 cells with LO originating from the parental cell line itself did not result in increased invasinevess, suggesting a specific role for EVs from aggressive cells. In addition, in order to investigate LO content, we focused our attention on a cell surface glycoprotein, CUB domain-containing protein 1 (CDCP-1), putatively linked to the network of proteins identified in DU145R80 cells and whose role in cancer is still under debate. Our results demonstrate that CDCP-1 expression is significantly reduced in DU145R80 compared to DU145 cells, suggesting a tumor-protective role for the protein in prostate cancer. We also observed, for the first time, that the CDCP-1 expression pattern displayed by both cell lines was reflected in their derived LO. These data intriguingly suggest that CDCP-1 may change its expression pattern upon modifications in tumor cells properties, playing a different role in different stages of cancer development. Overall, these findings highlight LO as a new biological component in the development of aggressive features by prostate cancer cells, connecting molecular alterations to changes in the ability to interact with the surrounding environment, and suggested new prognostic markers and/or therapeutical targets. Citation Format: Chiara Ciardiello, Valentina R. Minciacchi, Mariana Reis-Sobreiro, Maria R. Milone, Biagio Pucci, Rita Lombardi, Francesca Bruzzese, Dolores Di Vizio, Alfredo Budillon. Large oncosomes derived from the aggressive prostate cancer sub-line, DU145R80, can modify the biological behavior of the parental DU145 cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4154. doi:10.1158/1538-7445.AM2015-4154</jats:p

Synergistic Integration of a Ru(bda)-Based Catalyst in a Covalent Organic Framework for Enhanced Photocatalytic Water Oxidation

To address the urgent need for sustainable energy processes, there is a growing demand for multifunctional materials that mimic natural photosynthetic enzyme functions, specifically light-harvesting, efficient photoinduced charge separation, and integration of molecularly defined catalysts, synergistically interacting within these structures. Herein, the successful synthesis of an innovative Covalent Organic Framework (COF-TFPT-IsoQ) constructed from optically active triazine (TFPT) and isoquinoline units (IsoQ) as building blocks is reported. Post-synthetic incorporation of a Ru(bda)-based water oxidation catalyst (WOC) is achieved through the IsoQ moieties acting as coordinating sites. Leveraging the synthetic flexibility of the designed COF architecture featuring binding sites on its pore walls, various Ru@COF-TFPT-IsoQ systems at different Ru:COF ratios are synthesized and tested in the photoinduced (λ > 400 nm) oxygen evolution reaction (OER) under sacrificial conditions. All synthesized Ru@COF-TFPT-IsoQ systems demonstrate efficiency in the photocatalytic OER, with the highest turnover number (TON) of 9.1 observed for the system where the Ru-based WOC is incorporated every fourth COF-TFPT-IsoQ unit cell. This work provides valuable insights into the structural integration and catalytic behavior of Ru-based complexes within COF architectures, highlighting the potential of Ru@COF-TFPT-IsoQ as a robust, efficient, and synthetically flexible multifunctional material for light-induced water oxidation catalysis.LR

Graphene Acetic Acid‐Based Hybrid Supercapacitor and Liquid‐Gated Transistor

Abstract Supercapacitors and transistors are two key devices for future electronics that must combine portability, high performance, easy scalability, etc. Graphene‐related materials (GRMs) are frequently chosen as active materials for these applications given their unique physical properties that are tunable via chemical functionalization. Up to date, among GRMs, only reduced graphene oxide (rGO) showed sufficient versatility and processability in mild media, rendering it suitable for integration in these two types of devices. Here, a sound alternative to rGO is provided, namely graphene acetic acid (GAA), whose physico‐chemical features offer specific advantages. In particular, the use of a GAA‐based cathode in a zinc hybrid supercapacitor (Zn‐HSC) delivers state‐of‐the‐art gravimetric capacitance of ≈400 F g−1 at a current density of 0.05 A g−1. Conversely, GAA‐based LGT, supported onto Si/SiO2, shows an ambipolar behavior in 0.1 m NaCl, featuring a clear p‐doping quantified by Dirac voltage higher than 100 mV. Such a device is successfully implemented in paper fluidics, thereby demonstrating the feasibility of real‐time monitoring

Large oncosomes overexpressing integrin alpha-V promote prostate cancer adhesion and invasion via AKT activation

Background: Molecular markers for prostate cancer (PCa) are required to improve the early definition of patient outcomes. Atypically large extracellular vesicles (EVs), referred as "Large Oncosomes" (LO), have been identified in highly migratory and invasive PCa cells. We recently developed and characterized the DU145R80 subline, selected from parental DU145 cells as resistant to inhibitors of mevalonate pathway. DU145R80 showed different proteomic profile compared to parental DU145 cells, along with altered cytoskeleton dynamics and a more aggressive phenotype. Methods: Immunofluorescence staining and western blotting were used to identify blebbing and EVs protein cargo. EVs, purified by gradient ultra-centrifugations, were analyzed by tunable resistive pulse sensing and multi-parametric flow cytometry approach coupled with high-resolution imaging technologies. LO functional effects were tested in vitro by adhesion and invasion assays and in vivo xenograft model in nude mice. Xenograft and patient tumor tissues were analyzed by immunohistochemistry. Results: We found spontaneous blebbing and increased shedding of LO from DU145R80 compared to DU145 cells. LO from DU145R80, compared to those from DU145, carried increased amounts of key-molecules involved in PCa progression including integrin alpha V (αV-integrin). By incubating DU145 cells with DU145R80-derived LO we demonstrated that αV-integrin on LO surface was functionally involved in the increased adhesion and invasion of recipient cells, via AKT. Indeed either the pre-incubation of LO with an αV-integrin blocking antibody, or a specific AKT inhibition in recipient cells are able to revert the LO-induced functional effects. Moreover, DU145R80-derived LO also increased DU145 tumor engraftment in a mice model. Finally, we identified αV-integrin positive LO-like structures in tumor xenografts as well as in PCa patient tissues. Increased αV-integrin tumor expression correlated with high Gleason score and lymph node status. Conclusions: Overall, this study is the first to demonstrate the critical role of αV-integrin positive LO in PCa aggressive features, adding new insights in biological function of these large EVs and suggesting their potential use as PCa prognostic markers

Additional file 1: of Large oncosomes overexpressing integrin alpha-V promote prostate cancer adhesion and invasion via AKT activation

Supplementary Material and Methods. (DOCX 23 kb

Additional file 3: of Large oncosomes overexpressing integrin alpha-V promote prostate cancer adhesion and invasion via AKT activation

Figure S2. Surface integrin profile in DU145 compared to DU145R80 cells. Integrins profile on both DU145 and DU145R80 cell surface. Results are representative of a single experiment performed in triplicate. SD are reported. At least three experiments yielded similar results. (PDF 109 kb

Additional file 7: of Large oncosomes overexpressing integrin alpha-V promote prostate cancer adhesion and invasion via AKT activation

Figure S6. Kinetic of xenograft tumor growth in nude mice and tumor sample analysis. (A) Hematoxylin and eosin and (B) tumor volume curves of xenograft indicated tumors in nude mice. Negative ÎąV-integrin staining on mice (C) normal lymph node (D) lung ((E) xenograft tumor sample (DU145R80 group) incubated only with secondary antibody. (PDF 186 kb