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PubMed | Anhui Medical University, Xiamen University, Guangzhou Redsun Gas Applications Co., Anhui University of Science and Technology and South China University of Technology
Type: Journal Article | Journal: Nanoscale | Year: 2016

Many of the neurodegenerative disorders such as Huntingtons disease (HD) are caused by the accumulation of intracytoplasmic aggregate-prone proteins. These toxic protein aggregates are mainly degraded by autophagy, thus elevating the autophagy level to enhance the degradation of these proteins representing an emerging viable approach for the treatment of neurodegenerative diseases. In this report we showed that graphene oxide (GO), an engineered nanomaterial with enormous potential in biomedical applications, effectively enhanced the clearance of mutant huntingtin (Htt), the aggregate-prone protein underlying the pathogenesis of HD. This enhancing effect of GO was autophagy-mediated, as blocking autophagy by chemical inhibitors at either the autophagosome formation stage or the autophagosome-lysosome fusion stage, or more specifically by knocking-down an essential autophagy gene, led to a significant reduction in the ability of GO to elicit Htt degradation. Interestingly, the autophagy induced by GO had the normal capacity to degrade its cargo including LC3-II and Htt, but not p62/SQSTM1 (p62), and was dependent on the activation of class III phosphatidylinositol 3-kinase (PtdIns3K) and MEK/ERK1/2 signaling pathways, without mTOR involvement. GO also increased ubiquitination of Htt, an event necessary for Htts clearance. Furthermore, ubiquitinated huntingtin protein preferentially binds to GO, and abundant GO was found in autophagosomes and autolysosomes, thus raising the possibility that GO may directly deliver the bound protein to autophagosomes for degradation. Our results revealed a novel biological function of GO and may have implications for developing nanomaterial-based therapeutics for neurodegenerative diseases.


Fu N.,South China University of Technology | Fu N.,Guangzhou Redsun Gas Applications Co. | Fu N.,Hong Kong Polytechnic University | Liu Y.,Hong Kong Polytechnic University | And 5 more authors.
Journal of Materials Chemistry A | Year: 2015

In the present work, we developed a facile post-treatment approach, namely one-step hot-water soaking, to the fabrication of double-layer and hierarchical TiO2 nanotube arrays (H-TNTAs) comprising a nanoparticle/nanotube hybrid layer and a TiO2 nanowire cap layer for highly efficient dye-sensitized solar cells (DSSCs). The nanoparticle/nanotube hybrid structure of the H-TNTA provides enormous specific surface area for sufficient dye attachment and the TiO2 nanowire cap layer serves as a light-scattering layer with increased dye-absorption for superior light harvesting efficiency. This engineered integration makes it possible to control the dye-anchoring, charge transport, charge collection, and light scattering within a photoanode simultaneously. The DSSC based on the well tailored architecture yields an exciting power conversion efficiency of 8.21% under 100 mW cm-2, corresponding to 51% improvement as compared with the cell built on the pristine TNTA (P-TNTA, 5.43%). The efficiency can be further improved to 8.82% when the H-TNTA photoanodes are subjected to an additional TiCl4 treatment. © The Royal Society of Chemistry 2015.


Fu N.,South China University of Technology | Fu N.,Guangzhou Redsun Gas Applications Co. | Fu N.,Hong Kong Polytechnic University | Huang C.,Hong Kong Polytechnic University | And 7 more authors.
ACS Applied Materials and Interfaces | Year: 2015

Recently, the synthesis of fine TiO2 paste with organic-free binder emerged as an indispensable technique for plastic photovoltaics due to the low temperature processing requirement. In this study, pure anatase TiO2 nanoparticles and organic-free TiO2-sol were successfully synthesized individually in organic-free solution. By mixing the pure anatase TiO2 with the newly developed TiO2-sol binder, mechanically robust and well-interconnected TiO2 films were prepared via UV-irradiation at low temperature for applications in plastic dye-sensitized solar cells (p-DSSCs). The structural, electrical, and photovoltaic properties of the films as well as the devices were investigated by various techniques. The dye-loading amount of the obtained film is 2.6 times that of the P25 electrodes. As revealed by electrochemical impedance spectroscopy results, the film derived from the as-prepared anatase TiO2 paste (A-TiO2) exhibits much smaller charge transport resistance and lower electron recombination rate than the P25 film, while the introduction of TiO2-sol into the paste can further remarkably decrease the resistance of the produced film (AS-TiO2). The p-DSSCs employing AS-TiO2 photoanode yield a high efficiency up to 7.51%, which is 86% higher than the P25 reference cells and also 31% higher than the A-TiO2 cell. As a proof of concept, the newly developed AS-TiO2 paste was also applied to low temperature processed perovskite solar cells (PSCs), and a promising high efficiency up to 9.95% was achieved. © 2015 American Chemical Society.


PubMed | Hong Kong Polytechnic University, Guangzhou Redsun Gas Applications Co. and South China University of Technology
Type: Journal Article | Journal: ACS applied materials & interfaces | Year: 2015

Recently, the synthesis of fine TiO2 paste with organic-free binder emerged as an indispensable technique for plastic photovoltaics due to the low temperature processing requirement. In this study, pure anatase TiO2 nanoparticles and organic-free TiO2-sol were successfully synthesized individually in organic-free solution. By mixing the pure anatase TiO2 with the newly developed TiO2-sol binder, mechanically robust and well-interconnected TiO2 films were prepared via UV-irradiation at low temperature for applications in plastic dye-sensitized solar cells (p-DSSCs). The structural, electrical, and photovoltaic properties of the films as well as the devices were investigated by various techniques. The dye-loading amount of the obtained film is 2.6 times that of the P25 electrodes. As revealed by electrochemical impedance spectroscopy results, the film derived from the as-prepared anatase TiO2 paste (A-TiO2) exhibits much smaller charge transport resistance and lower electron recombination rate than the P25 film, while the introduction of TiO2-sol into the paste can further remarkably decrease the resistance of the produced film (AS-TiO2). The p-DSSCs employing AS-TiO2 photoanode yield a high efficiency up to 7.51%, which is 86% higher than the P25 reference cells and also 31% higher than the A-TiO2 cell. As a proof of concept, the newly developed AS-TiO2 paste was also applied to low temperature processed perovskite solar cells (PSCs), and a promising high efficiency up to 9.95% was achieved.

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