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Electrical Conductance in Biological Molecules
Waleed Shinwari, M.,Jamal Deen, M.,Starikov, Evgeni B.,Cuniberti, Gianaurelio WILEY-VCH Verlag 2010 Advanced Functional Materials Vol.20 No.12
<P>Nucleic acids and proteins are not only biologically important polymers. They have recently been recognized as novel functional materials surpassing conventional materials in many aspects. Although Herculean efforts have been undertaken to unravel fine functioning mechanisms of the biopolymers in question, there is still much more to be done. Here the topic of biomolecular charge transport is presented with a particular focus on charge transfer/transport in DNA and protein molecules. The experimentally revealed details, as well as the presently available theories, of charge transfer/transport along these biopolymers are critically reviewed and analyzed. A summary of the active research in this field is also given, along with a number of practical recommendations.</P> <B>Graphic Abstract</B> <P>Biomolecular charge transport is presented, with a particular focus on charge transfer/transport in DNA and protein molecules. The experimental data, as well as the presently available theories, are critically reviewed and analyzed. A summary of the active research in this field is also given, along with a number of practical recommendations. <img src='wiley_img_2010/1616301X-2010-20-12-ADFM200902066-content.gif' alt='wiley_img_2010/1616301X-2010-20-12-ADFM200902066-content'> </P>
Waleed Ahmed El-Said,예철헌,권일근,최정우 한국바이오칩학회 2009 BioChip Journal Vol.3 No.2
The effect of anticancer drugs and toxins on the viabiity of HepG2 cells were examined by the cyclic voltammetry (CV) and the potentiometric stripping analysis (PSA) methods. The cells were immobilized on gold patterned silicon substrate. The voltammetric behaviors of HepG2 cells showed a quasi-reversible process and the peak current showed a linear relationship with cell number. The attached living cells were treated with different concentrations of anticancer drugs and toxin. As the exposed concentrations of anticancer drugs and toxins were increased, we observed that the peak current in CV assay and the area under the peak in PSA assay were decreased. Trypan blue dyeing experiment was performed to confirm the results of the effects of anticancer drugs on the cell viability which were obtained from CV assay and PSA assay. These results indicate that the proposed direct cell immobilization method technique can be applied to construct the cell chip for the diagnosis, drug detection, and on-site monitoring depended on the voltammetric and PSA methods.
Waleed Ahmed El-Said,Cheol-Heon Yea,Hyunhee Kim,최정우 한국물리학회 2009 Current Applied Physics Vol.9 No.2
HepG2 cells have been immobilized on nanoscale self-assembled synthetic oligopeptide modified chip surface and subsequently used for anticancer drug screening. Nanoscale controlled self-assembled peptide layer was investigated by AFM (Atomic Force Microscopy). The immobilization of HepG2 cells on nanoscale controlled surface was investigated by using Raman spectroscopy. HepG2 cells were grown on peptide modified gold surface acting as working electrode. The AFM investigation of the oligopeptide modified surface showed excellent agreement with the nanoscale nature of the peptide modification, and the voltammetric response of HepG2 cells on this surface towards an anticancer drug showed a linear relationship with the cell number. As an application, electrochemical detection of anticancer drug effect of HepG2 cells was shown. These results indicate that RGD (Arg-Gly-Asp) peptide self-assembled layer mediated the cell immobilization technique and the voltammetric signal analysis system can be applied to construct a cell chip for diagnosis, drug detection, and on-site monitoring. HepG2 cells have been immobilized on nanoscale self-assembled synthetic oligopeptide modified chip surface and subsequently used for anticancer drug screening. Nanoscale controlled self-assembled peptide layer was investigated by AFM (Atomic Force Microscopy). The immobilization of HepG2 cells on nanoscale controlled surface was investigated by using Raman spectroscopy. HepG2 cells were grown on peptide modified gold surface acting as working electrode. The AFM investigation of the oligopeptide modified surface showed excellent agreement with the nanoscale nature of the peptide modification, and the voltammetric response of HepG2 cells on this surface towards an anticancer drug showed a linear relationship with the cell number. As an application, electrochemical detection of anticancer drug effect of HepG2 cells was shown. These results indicate that RGD (Arg-Gly-Asp) peptide self-assembled layer mediated the cell immobilization technique and the voltammetric signal analysis system can be applied to construct a cell chip for diagnosis, drug detection, and on-site monitoring.
Waleed Ahmed El-Said,최정우 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.6
Rat pheochromocytoma PC12 cells havefrequently been used as a dopaminergic neuron model dueto their various functions, including the synthesis, storage,and secretion of catecholamines. Furthermore, PC12 cellsrelease a measurable amount of dopamine (DA) in responseto some chemicals. PC12 cells are thus considered to beone of the most common invitro models for studyingneurotransmitter release. Here, we applied Surface-enhancedRaman Spectroscopy (SERS) to determine with highsensitivity the in-situ short-time effects of cisplatin (cisdiamine-dichloroplatinum), bisphenol-A, and cyclophosphamideon the extracellular DA level released from PC12cells. In addition, using the SERS technique, changes in thebiochemical composition of the PC12 cell lysates wereinvestigated to determine the intracellular DA level. Goldnano-patterned substrates were fabricated based on electrochemicaldeposition of Au nanorods onto ITO substrates;these substrates were then used as SERS-active surfaces. The Raman spectroscopy results demonstrated that thechanges in the Raman spectra depending on the treatmentagent were in agreement with the HPLC results on theextracellular DA level. Therefore, the SERS technique canovercome the limitations of other detection techniques, andcan be used with cellular nanoarrays to study the effect ofa wide range of chemicals.
Waleed Mashrah,Zhi-Hua Chen,Rima Boufendassa,Hongbo Liu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.9
The joint’s cyclic behaviour and energy-dissipation capacity are important in lattice shell structures' resisting wind and seismic load capacities. Based on the bending test and FE analysis of the novel steel dovetail joint in the previous study, a full-scaled FE model with six H-shaped beams was analysed using the Abaqus program to determine the boundary conditions for the FE models of hysteric analysis. In the cyclic analysis, 1/6 FE models of the novel steel dovetail joints (NDJGs) were established and analysed based on the boundary conditions of the full FE model in the bending analysis and Quasi-static analysis step. The loading protocol is defined, and the analysis is carried out considering different design parameters, including hub ring thickness, slot edge thickness, and teeth depth. The analysis results indicated that the hub ring thickness does not affect the cyclic bending capacity and stiffness of the novel steel dovetail joint; meanwhile, they increased gradually when the slot edge increased. At the same time, the bending capacity is negatively correlated with the teeth depth, where the bending capacity is reduced when the teeth depth increases. All skeleton curves for all joints of this study are compared, and their energy-dissipation capacities and ductility are calculated. Finally, the novel steel dovetail joint showed an excellent energy-dissipation capacity with high ductility performance under cyclic loads.