Chen J.,CAS Changchun Institute of Applied Chemistry |
Dong X.,CAS Changchun Institute of Applied Chemistry |
Dong X.,Xiamen Institute of Measurement and Testing |
Feng T.,CAS Changchun Institute of Applied Chemistry |
And 6 more authors.
A novel pH-responsive gene delivery system for tumor acidity-targeted pDNA delivery is prepared by introducing a rapid charge-conversional zwitterionic copolymer to the positive surface of PEI/pDNA complexes through electrostatic interaction. The shielding system (OEAL) consists of oligoethylenimine (OEI), poly(l-aspartate) (PBLA), and poly(l-lysine) (PLL). The charge-conversional behavior of the OEAL/PEI/DNA ternary complex is evaluated by zeta potential assay. The surface charges of the complexes can change from negative to positive in the pH range of 7.4-6.8. Under a simulative in vivo environment, OEAL/PEI/DNA exhibits promotion of cellular uptake by tumor cells and enhanced gene transfection efficiency because of its good charge-conversional properties. Antitumor experiments further show that the pH-responsive charge-conversional system can mediate a therapeutic gene that can induce tumor apoptosis (pKH3-rev-casp-3) to achieve effective tumor inhibition. Accordingly, OEAL can be regarded as a promising tumor microenvironment-sensitive gene delivery shielding system for antitumor therapy. Statement of Significance This manuscript focused on the novel pH-responsive gene delivery system for tumor acidity-targeted pDNA delivery. The novel system is prepared by introducing a rapid charge-conversional zwitterionic copolymer, consisting of oligoethylenimine, poly(l-aspartate) and poly(l-lysine), to the positive surface of PEI/pDNA complexes. The surface charges of the complexes can change from negative to positive from pH 7.4 to 6.8. OEAL/PEI/DNA shows promoting cellular uptake by tumor cells and enhanced gene transfection efficiency. The antitumor experiments further show that the pH responsive charge conversional system can mediate pKH3-rev-casp-3 to achieve effective tumor inhibition. Accordingly, OEAL can be regarded as a promising tumor microenvironment sensitive gene delivery shielding system for antitumor therapy. © 2015 Acta Materialia Inc. Published by Elsevier Ltd. Source
Lai S.,Xiamen University |
Mao D.,Xiamen University |
Ruan Y.,Xiamen Institute of Measurement and Testing |
Xu Y.,Xiamen University |
And 6 more authors.
Materials Science and Engineering B: Solid-State Materials for Advanced Technology
Severe Fermi level pinning at the interface of metal/n-Ge leads to the formation of a Schottky barrier. Therefore, a high contact resistance is introduced, debasing the performance of Ge devices. In this study, a Ge surface was treated by nitrogen plasma to form an ultra-thin Germanium oxynitride (GeOxNy) passivation layer. It was found that the Schottky barrier height (SBH) of metal/n-Ge contact was strongly modulated by the GeOxNy interlayer, indicating alleviation of Fermi-level pinning effect. By adjusting the principal parameters of N2 plasma treatment and additional post anneal, a Quasi-ohmic Al/n-Ge contact was achieved. Furthermore, the introduced GeOxNy layer gave extremely lower leakage current density of the gate stack for HfO2/Ge devices. These results demonstrate that GeOxNy formed by N2 plasma would be greatly beneficial to the fabrication of the Ge-based devices. © 2016 Elsevier B.V. Source
Shi Y.,Xiamen Institute of Measurement and Testing
Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams
A surface profile measurement visualization method of large aspheric lenses based on doubly-connected edge list (DCEL) are proposed, and a software system is designed and developed to realize it. Firstly, an improved data structure based on DCEL is proposed to load 3D model. The graphics units which compose the basic part of the software are modeled based on DCEL data structure. Secondly, the scene node which composes the display part of software is created by aspheric surface profile according to surface equation. And the measurement path is generated and displayed by the software. An experiment was performed on the noncontact measurement platform. The data were integrated and smoothed to compare with the equation of aspheric surface contour and then the peak-valley value and RMS value of the surface were calculated. The experiment indicates that the surface profile measurement visualization method is correct and stable. Source