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Nanoscale ; 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34617545


It is of great importance to develop efficient and low-cost oxygen evolution reaction (OER) electrocatalysts for electrochemical water splitting. Herein, S doped NiCoVOx nanosheets grown on Ni-Foam (S-NiCoVOx/NF) with a modified electronic structure have been prepared through a facile one-step hydrothermal method. The as-prepared S4.06-NiCoVOx/NF exhibits outstanding OER activity with low overpotentials of 248 mV and 289 mV to deliver current densities of 10 mA cm-2 and 100 mA cm-2, respectively, and a small Tafel slope of 46.2 mV dec-1 in 1.0 M KOH electrolyte. These values are much lower than those obtained for most of the recently reported non-noble metal-based electrocatalysts under similar experimental conditions. This study provides a simple approach to rational design of efficient and cost-effective OER electrocatalysts for practical application of electrochemical water splitting.

Mater Sci Eng C Mater Biol Appl ; 128: 112333, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474884


Polyetheretherketone (PEEK) was widely applied into fabricating of orthopaedic implants, benefitting its excellent biocompatibility and similar mechanical properties to native bones. However, the inertness of PEEK hinders its integration with the surrounding bone tissue. Here PEEK scaffolds with a series of hydroxyapatite (HA) contents in gradient were manufactured via fused filament fabrication (FFF) 3D printing techniques. The influence of the pore size, HA content and printing direction on the mechanical properties of the PEEK/HA scaffolds was systematically evaluated. By adjusting the pore size and HA contents, the elastic modulus of the PEEK/HA scaffolds can be widely tuned in the range of 624.7-50.6 MPa, similar to the variation range of natural cancellous bone. Meanwhile, the scaffolds exhibited higher Young's modulus and lower compressive strength along Z printing direction. The mapping relationship among geometric parameters, HA content, printing direction and mechanical properties was established, which gave more accurate predictions and controllability of the modulus and strength of scaffolds. The PEEK/HA scaffolds with the micro-structured surface could promote cell attachment and mineralization in vitro. Therefore, the FFF-printed PEEK/HA composites scaffolds can be a good candidate for bone grafting and tissue engineering.

Durapatita , Cetonas , Benzofenonas , Polietilenoglicóis , Polímeros , Porosidade , Impressão Tridimensional , Tecidos Suporte
Eur J Med Chem ; 224: 113671, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34237623


Hepatocellular carcinoma (HCC) is the most common form of liver cancer and the fourth leading cause of cancer-related death worldwide. First-line drugs such as sorafenib provide only a modest benefit to HCC patients. In this study, the gram-scale synthesis of 2-benzoylquinazolin-4(3H)-one skeleton was achieved successfully via the I2/DMSO catalytic system. A series of penipanoid C-inspired 2-(3,4,5-trimethoxybenzoyl)quinazolin-4(3H)-one derivatives was synthesized and evaluated for their cytotoxic activities against four cancer cell lines, HepG2, Bel-7402, A549, and U251. Among these compounds, 4a was the most effective one with IC50 values of 1.22 µM and 1.71 µM against HepG2 and Bel-7402 cells, respectively. Mechanistic studies showed that 4a inhibited hepatocellular carcinoma cell proliferation via arresting cell cycle. Additionally, 4a induced HepG2 cells apoptosis by inducing reactive oxygen species production and elevating the expression of apoptosis-related proteins. More importantly, 4a displayed significant in vivo anticancer effects in the HepG2 xenograft models. This suggests that 4a is a promising lead compound with the potential to be developed as a chemotherapy agent for hepatocellular carcinoma.

J Mech Behav Biomed Mater ; 118: 104475, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33773239


Polyether-ether-ketone (PEEK) exhibits excellent mechanical properties and biocompatibility. Three-dimensional (3D) printing of PEEK bone substitutes has been widely used in clinical application. However, the inertness of pure PEEK hinders its integration with the surrounding bone tissue. In this study, for the first time, PEEK/hydroxyapatite (HA) composite specimens were fabricated using fused filament fabrication (FFF) technology. PEEK/HA filaments with HA contents of 0-30 wt% were fabricated via mechanical mixing and extrusion. The HA distributions inside the composite matrix and the surface morphology characteristics of the PEEK/HA composites were examined. The effects of the printing path and HA content on the mechanics of the PEEK/HA composites were systematically investigated. The results indicated that the HA particles were uniformly distributed on the composite matrix. With an increase in the HA content, the modulus of the PEEK/HA composite increased, while the strength and failure strain concomitantly decreased. When the HA content increased to 30 wt%, the tensile modulus of the composite increased by 68.6% compared with that of pure PEEK printed along the horizontal 90° path, while the tensile strength decreased by 48.2% compared with that of pure PEEK printed along the vertical 90° path. The fracture elongation of the printed specimens with different HA contents decreased in the following order: horizontal 0° > horizontal 90° > vertical 90°. The best comprehensive mechanical properties were achieved for pure PEEK fabricated along the horizontal 0° path. The results indicate that FFF technology is applicable for additive manufacturing of PEEK/HA composites with controllable compositions. Printed PEEK/HA composites have potential for applications in the design and manufacturing of personalized bone substitutes.

Materiais Biocompatíveis , Durapatita , Éteres , Cetonas , Polietilenoglicóis , Impressão Tridimensional
Cell Death Dis ; 10(5): 329, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30988280


Protein S-nitrosylation, the redox-based posttranslational modification of a cysteine thiol by the attachment of a nitric oxide (NO) group, is responsible for a variety of signaling effects. Dysregulation of S-nitrosylation may be directly linked to cancer apoptotic resistance and cancer therapy outcomes, emphasizing the importance of S-nitrosylation in cancer. Peroxiredoxin-2 (Prdx2), an antioxidant enzyme, plays an important role in the protection of cancer cells from oxidative radical damage caused by hydrogen dioxide (H2O2), which is a potential target for cancer therapy. Our studies showed that, as an endogenous NO carrier, S-nitrosoglutathione (GSNO) induced apoptosis in lung cancer cells via nitrosylating Prdx2. The nitrosylation of Prdx2 at Cys51 and Cys172 sites disrupted the formation of Prdx2 dimer and repressed the Prdx2 antioxidant activity, causing the accumulation of endogenous H2O2. H2O2 activated AMPK, which then phosphorylated SIRT1 and inhibited its deacetylation activity toward p53 in A549 cells or FOXO1 in NCI-H1299 cells. Taken together, our results elucidate the roles and mechanisms of Prdx2 S-nitrosylation at Cys51 and Cys172 sites in lung cancer cells apoptosis and this finding provides an effective lung cancer treatment strategy for managing aberrant Prdx2 activity in lung cancers.

Apoptose/efeitos dos fármacos , Peroxirredoxinas/metabolismo , S-Nitrosoglutationa/farmacologia , Transdução de Sinais/efeitos dos fármacos , Proteínas Quinases Ativadas por AMP/antagonistas & inibidores , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular , Proteína Forkhead Box O1/metabolismo , Humanos , Peróxido de Hidrogênio/metabolismo , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Óxido Nítrico/metabolismo , Peroxirredoxinas/antagonistas & inibidores , Peroxirredoxinas/genética , Fosforilação , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Sirtuína 1/antagonistas & inibidores , Sirtuína 1/genética , Sirtuína 1/metabolismo
Biochem Biophys Res Commun ; 512(2): 269-275, 2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-30885438


The antineoplastic activity of host defense peptide Hymenochirin-1B, has been extensively studied. However, the mechanism still remains unknown. In this study, linear peptide, Hymenochirin-1B, was synthesized via solid-phase peptide synthesis and evaluated for its anticancer efficacy. We found Hymenochirin-1B induced lung cancer cell apoptosis and cell cycle arrest at the G0/G1 phase. Moreover, Hymenochirin-1B could enter the cells and colocalized with mitochondria. Furthermore, decrease of mitochondrial membrane potential, increase of reactive oxygen species and the expression of apoptosis-associated protein (Bax/Bcl-2 ratio and activated Caspase-3) were observed in NCI-H1299 and A549 cells after Hymenochirin-1B treatment, suggesting that Hymenochirin-1B induced apoptosis via mitochondrial pathway. Our results provide new insights on the anticancer mechanism of Hymenochirin-1B, which may contribute to its further development into an antineoplastic drug in the future.

Peptídeos Catiônicos Antimicrobianos/farmacologia , Antineoplásicos/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Células A549 , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Células Hep G2 , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ensaio Tumoral de Célula-Tronco , Proteína X Associada a bcl-2/metabolismo