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Probing the Electron Transfer between iLOV Protein and Ag Nanoparticles.
Ran, X, Zhang, Q, Zhang, Y, Chen, J, Wei, Z, He, Y, Guo, L
Molecules (Basel, Switzerland). 2020;(11)
Abstract
Nanomaterials have been widely used in biomedical sciences; however, the mechanism of interaction between nanoparticles and biomolecules is still not fully understood. In the present study, we report the interaction mechanism between differently sized Ag nanoparticles and the improved light-oxygen-voltage (iLOV) protein. The steady-state and time-resolved fluorescence results demonstrated that the fluorescence intensity and lifetime of the iLOV protein decreased upon its adsorption onto Ag nanoparticles, and this decrease was dependent upon nanoparticle size. Further, we showed that the decrease of fluorescence intensity and lifetime arose from electron transfer between iLOV and Ag nanoparticles. Moreover, through point mutation and controlled experimentation, we demonstrated for the first time that electron transfer between iLOV and Ag nanoparticles is mediated by the tryptophan residue in the iLOV protein. These results are of great importance in revealing the function of iLOV protein as it applies to biomolecular sensors, the field of nano-photonics, and the interaction mechanism between the protein and nanoparticles.
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Electrically controlled mass transport into microfluidic droplets from nanodroplet carriers with application in controlled nanoparticle flow synthesis.
Gu, T, Zheng, C, He, F, Zhang, Y, Khan, SA, Hatton, TA
Lab on a chip. 2018;(9):1330-1340
Abstract
Microfluidic droplets have been applied extensively as reaction vessels in a wide variety of chemical and biological applications. Typically, once the droplets are formed in a flow channel, it is a challenge to add new chemicals to the droplets for subsequent reactions in applications involving multiple processing steps. Here, we present a novel and versatile method that employs a high strength alternating electrical field to tunably transfer chemicals into microfluidic droplets using nanodroplets as chemical carriers. We show that the use of both continuous and cyclic burst square wave signals enables extremely sensitive control over the total amount of chemical added and, equally importantly, the rate of addition of the chemical from the nanodroplet carriers to the microfluidic droplets. An a priori theoretical model was developed to model the mass transport process under the convection-controlled scenario and compared with experimental results. We demonstrate an application of this method in the controlled preparation of gold nanoparticles by reducing chloroauric acid pre-loaded in microfluidic droplets with l-ascorbic acid supplied from miniemulsion nanodroplets. Under different field strengths, l-ascorbic acid is supplied in controllable quantities and addition rates, rendering the particle size and size distribution tunable. Finally, this method also enables multistep synthesis by the stepwise supply of miniemulsions containing different chemical species. We highlight this with a first report of a three-step Au-Pd core-shell nanoparticle synthesis under continuous flow conditions.
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3.
Piezotronic-effect enhanced drug metabolism and sensing on a single ZnO nanowire surface with the presence of human cytochrome P450.
Wang, N, Gao, C, Xue, F, Han, Y, Li, T, Cao, X, Zhang, X, Zhang, Y, Wang, ZL
ACS nano. 2015;(3):3159-68
Abstract
Cytochromes P450 (CYPs) enzymes are involved in catalyzing the metabolism of various endogenous and exogenous compounds. A rapid analysis of drug metabolism reactions by CYPs is required because they can metabolize 95% of current drugs in drug development and effective therapies. Here, we describe a study of piezotronic-effect enhanced drug metabolism and sensing by utilizing a single ZnO nanowire (ZnO NW) device. Owing to the unique hydrophobic feature of a ZnO NW that provides a desirable "microenvironment" for the immobilization of biomolecules, our device can effectively stimulate the tolbutamide metabolism by decorating a ZnO NW with cytochrome P4502C9/CYPs reductase (CYP2C9/CPR) microsomes. By applying an external compressive strain to the ZnO nanowire, the piezotronic effect, which plays a primary role in tuning the transport behavior of a ZnO NW utilizing the created piezoelectric polarization charges at the local interface, can effectively enhance the performance of the device. A theoretical model is proposed using an energy band diagram to explain the experimental data. This study provides a potential approach to study drug metabolism and trace drug detection based on the piezotronic effect.
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4.
Rectangular coordination polymer nanoplates: large-scale, rapid synthesis and their application as a fluorescent sensing platform for DNA detection.
Zhang, Y, Luo, Y, Tian, J, Asiri, AM, Al-Youbi, AO, Sun, X
PloS one. 2012;(1):e30426
Abstract
In this paper, we report on the large-scale, rapid synthesis of uniform rectangular coordination polymer nanoplates (RCPNs) assembled from Cu(II) and 4,4'-bipyridine for the first time. We further demonstrate that such RCPNs can be used as a very effective fluorescent sensing platform for multiple DNA detection with a detection limit as low as 30 pM and a high selectivity down to single-base mismatch. The DNA detection is accomplished by the following two steps: (1) RCPN binds dye-labeled single-stranded DNA (ssDNA) probe, which brings dye and RCPN into close proximity, leading to fluorescence quenching; (2) Specific hybridization of the probe with its target generates a double-stranded DNA (dsDNA) which detaches from RCPN, leading to fluorescence recovery. It suggests that this sensing system can well discriminate complementary and mismatched DNA sequences. The exact mechanism of fluorescence quenching involved is elucidated experimentally and its use in a human blood serum system is also demonstrated successfully.