Cationic and Anionic Surface Binding Sites on Nanocrystalline Zinc Oxide: Surface Influence on Photoluminescence and Photocatalysis

2009 ◽  
Vol 131 (12) ◽  
pp. 4397-4404 ◽  
Author(s):  
D. Scott Bohle ◽  
Carla J. Spina
Keyword(s):  
Zinc Oxide ◽  
Binding Sites ◽  
Oxide Surface ◽  
Surface Binding ◽  
Nanocrystalline Zinc Oxide ◽  
Anionic Surface

Electrically Tunable Ultra-specific Zinc Oxide Biosensor

2015 ◽  
Vol 1720 ◽  
Author(s):  
Rujuta D. Munje ◽  
Andi Wangzhou ◽  
Anjan Panneer Selvam ◽  
Sriram Muthukumar ◽  
Shalini Prasad
Keyword(s):  
Zinc Oxide ◽  
Electrochemical Impedance ◽  
Surface States ◽  
Green Emission ◽  
High Specificity ◽  
Oxide Surface ◽  
Surface Binding ◽  
Fluorescence Studies ◽  
Enhanced Sensitivity ◽  
Study Results

ABSTRACTZinc oxide surface states can be utilized for ultra-specific detection of biomolecules. The major challenges in using ZnO for bio-sensing are attaining enhanced sensitivity and specificity. In this study, we explore the functionalization of zinc in ZnO through utilizing the thiol bond. The purpose of this study is to demonstrate that the ZnO based sensor is capable of achieving high specificity in presence of competitive surface binding through the thiol bond. The final goal is to design an ultra-specific biosensor to detect low occurring biomolecules. In this study, we have selected cortisol as a stress marker to demonstrate quantification and detection from synthetic sweat. In order to demonstrate ultra-specificity, we have used two competitive thiol based molecules binding to zinc, a linker Dithiobis succinimidyl propionate (DSP) and reducing agent of DSP, Dithiothreitol (DTT). Electrochemical impedance spectroscopy (EIS) is used to quantify the signal obtained through various ratiometric concentrations of DSP and DTT. To validate the EIS study results, inherent fluorescence studies are done by mapping changes in green emission spectrum of ZnO before and after linker functionalization. The optimal combination in terms of highest signal is identified to be of 25mM DTT and 50mM DSP. This is implemented in the experiments performed to calibrate the cortisol concentration in synthetic sweat. This study demonstrates the detection of cortisol antigen in synthetic sweat present within the physiological levels of 8 ng/mL to 140 ng/mL.

scholarly journals Cell surface-binding sites for progesterone mediate calcium uptake in human sperm.

1991 ◽  
Vol 266 (28) ◽  
pp. 18655-18659 ◽  
Author(s):  
P.F. Blackmore ◽  
J. Neulen ◽  
F. Lattanzio ◽  
S.J. Beebe
Keyword(s):  
Cell Surface ◽  
Binding Sites ◽  
Calcium Uptake ◽  
Human Sperm ◽  
Surface Binding ◽  
Cell Surface Binding

Sphingosine 1-Phosphate Stimulates Fibronectin Matrix Assembly Through a Rho-Dependent Signal Pathway

Blood ◽  
1999 ◽  
Vol 93 (9) ◽  
pp. 2984-2990 ◽  
Author(s):  
Qinghong Zhang ◽  
Olivier Peyruchaud ◽  
Kelly J. French ◽  
Magnus K. Magnusson ◽  
Deane F. Mosher
Keyword(s):  
Binding Sites ◽  
Signal Pathway ◽  
Bioactive Lipids ◽  
Surface Binding ◽  
Matrix Assembly ◽  
Fibronectin Matrix ◽  
Mg63 Cells ◽  
Sphingosine 1 Phosphate ◽  
Common Signal ◽  
Stimulation Of

Abstract Fibronectin matrix assembly is a cell-dependent process mediated by cell surface binding sites for the 70-kD N-terminal portion of fibronectin. We have shown that Rho-dependent cytoskeleton reorganization induced by lysophosphatidic acid (LPA) or the microtubule-disrupting agent nocodazole increases fibronectin binding (Zhang et al, Mol Biol Cell 8:1415, 1997). Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid implicated in mitogenesis and cytoskeletal remodelling. Both LPA and S1P are present in increased amounts in serum as compared with plasma as a result of platelet activation. Addition of S1P to human osteosarcoma MG63 cells or human foreskin fibroblasts increased cell-mediated binding and assembly of fibronectin. MG63 cells expressed the Edg-2 and Edg-4 G-protein–coupled receptors for bioactive lipids, whereas foreskin fibroblasts expressed Edg-2, Edg-3, and Edg-4. The stimulatory effect of S1P on the binding of fibronectin or the N-terminal 70-kD fragment of fibronectin was dynamic and due to increases in both the number and affinity of binding sites. The stimulation of 70-kD fragment binding by nanomolar S1P, like stimulation of binding by LPA or nocodazole, was blocked by inactivation of Rho with C3 exotoxin but not by pertussis toxin-mediated inactivation of Gi. These results indicate a common signal pathway leading to control of cellular fibronectin matrix assembly by bioactive lipids generated during blood coagulation.

scholarly journals Microwave-assisted additive free synthesis of nanocrystalline zinc oxide

2010 ◽  
Vol 203 (2) ◽  
pp. 415-418 ◽  
Author(s):  
Kushal D. Bhatte ◽  
Pawan Tambade ◽  
Shin-ichiro Fujita ◽  
Masahiko Arai ◽  
Bhalchandra M. Bhanage
Keyword(s):  
Zinc Oxide ◽  
Microwave Assisted ◽  
Nanocrystalline Zinc Oxide

scholarly journals Ultrasound assisted additive free synthesis of nanocrystalline zinc oxide

2011 ◽  
Vol 18 (1) ◽  
pp. 54-58 ◽  
Author(s):  
Kushal D. Bhatte ◽  
Shin-Ichiro Fujita ◽  
Masahiko Arai ◽  
Anirudha B. Pandit ◽  
Bhalchandra M. Bhanage
Keyword(s):  
Zinc Oxide ◽  
Ultrasound Assisted ◽  
Nanocrystalline Zinc Oxide

ChemInform Abstract: Quantum Chemical Study of the Adsorption of Water on Zinc Oxide Surface.

ChemInform ◽  
2010 ◽  
Vol 25 (15) ◽  
pp. no-no
Author(s):  
J. B. L. MARTINS ◽  
E. LONGO ◽  
J. G. R. TOSTES ◽  
C. A. TAFT ◽  
J. ANDRES
Keyword(s):  
Zinc Oxide ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Oxide Surface ◽  
Adsorption Of Water

scholarly journals Fate of Internalized Thyrotropin-Releasing Hormone Receptors Monitored with a Timer Fusion Protein

Endocrinology ◽  
2004 ◽  
Vol 145 (7) ◽  
pp. 3095-3100 ◽  
Author(s):  
Laurie B. Cook ◽  
Patricia M. Hinkle
Keyword(s):  
Plasma Membrane ◽  
Binding Sites ◽  
Hormone Receptors ◽  
Inositol Phosphate ◽  
Fold Increase ◽  
Receptor Internalization ◽  
Free Calcium ◽  
Surface Binding ◽  
Cytoplasmic Vesicles ◽  
Trh Receptors

Abstract Trafficking of TRH receptors was studied in a stable HEK293 cell line expressing receptor fused to a Timer protein (TRHR-Timer) that spontaneously changes from green to red over 10 h. Cells expressing TRHR-Timer responded to TRH with an 11-fold increase in inositol phosphate formation, increased intracellular free calcium, and internalization of 75% of bound [3H][N3-methyl-His2]TRH within 10 min. After a 20-min exposure to TRH at 37 C, 75–80% of surface binding sites disappeared as receptors internalized. When TRH was removed and cells incubated in hormone-free medium, approximately 75% of [3H][N3-methyl-His2]TRH binding sites reappeared at the surface over the next 2 h with or without cycloheximide. Trafficking of TRHR-Timer was monitored microscopically after addition and withdrawal of TRH. In untreated cells, both new (green) and old (red) receptors were seen at the plasma membrane, and TRH caused rapid movement of young and old receptors into cytoplasmic vesicles. When TRH was withdrawn, some TRHR-Timer reappeared at the plasma membrane after several hours, but much of the internalized receptor remained intracellular in vesicles that condensed to larger structures in perinuclear regions deeper within the cell. Strikingly, receptors that moved to the plasma membrane were generally younger (more green) than those that underwent endocytosis. There was no change in the red to green ratio over the course of the experiment in cells exposed to vehicle. The results indicate that, after agonist-driven receptor internalization, the plasma membrane is replenished with younger receptors, arising either from an intracellular pool or preferential recycling of younger receptors.

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