Photophysics and Photocatalytic Properties of Cd(OH)2-Coated Q-CdS Clusters in the Presence of Guanine and Related Compounds

Kumar, Anil; Negi, Devendra P.S.

doi:10.1006/jcis.2001.7483

Cited by 13 publications

(6 citation statements)

References 32 publications

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“…Cross-linking agent 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) is used to couple molecules with carboxylic acid groups to molecules containing primary amines by forming amide bonds and was used in these experiments to bond either of two very different biomolecules to the solubilized quantum dot structures. Adenine (6-aminopurine or 6AP) is a small molecule (MW 135) that is redox-active; it is the most readily oxidized DNA base after guanine and has been shown to modify the steady-state and time-resolved emission properties of CdS nanocrystals . The protein transferrin is a large (80 kD) glycoprotein without redox activity that is expected to act as a simple passivating agent on the QD surface.…”

Section: Methodsmentioning

confidence: 99%

Photophysical Properties of Biologically Compatible CdSe Quantum Dot Structures

2005

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The photophysical properties of CdSe and ZnS(CdSe) semiconductor quantum dots in nonpolar and aqueous solutions were examined with steady-state (absorption and emission) and time-resolved (time-correlated single-photon-counting) spectroscopy. The CdSe structures were prepared from a single CdSe synthesis, a portion of which were ZnS-capped, thus any differences observed in the spectral behavior between the two preparations were due to changes in the molecular shell. Quantum dots in nonpolar solvents were surrounded with a trioctylphosphine oxide (TOPO) coating from the initial synthesis solution. ZnS-capped CdSe were initially brighter than bare uncapped CdSe and had overall faster emission decays. The dynamics did not vary when the solvent was changed from hexane to dichloromethane; however, replacement of the TOPO cap by pyridine affected CdSe but not ZnS(CdSe). CdSe was then solubilized in water with mercapto-acetic acid or dihydrolipoic acid, whereas ZnS(CdSe) could be solubilized only with dihydrolipoic acid. Both solubilization agents quenched the nanocrystal emission, though with CdSe the quenching was nearly complete. Additional quenching of the remaining emission was observed when the redox-active molecule adenine was conjugated to the water-soluble CdSe but was not seen with ZnS(CdSe). The emission of aqueous CdSe could be enhanced under prolonged exposure to room light and resulted in a substantial increase of the emission lifetimes; however, the enhancement occurred concurrently with precipitation of the nanocrystals, which was possibly caused by photocatalytic destruction of the mercaptoacetic acid coating. These results are the first presented on aqueous CdSe quantum dot structures and are presented in the context of designing better, more stable biological probes.

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Section: Methodsmentioning

confidence: 99%

Photophysical Properties of Biologically Compatible CdSe Quantum Dot Structures

2005

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“…Nucleic acids as another class of important biomolecules possess various metal-chelating functional groups such as phosphate, hydroxyl, and versatile nitrogen-containing groups and therefore can in principle be used as biotemplates to modulate the QD nucleation, growth, and surface passivation as well. ,,,, Benefiting from the engineerable structure of nucleic acids, the size, morphology, and optical properties of the QDs can largely be tuned apart from endowing the QD particle with recognition properties and chemical reactivity . In addition, nucleosides − and nucleotides ,− as the fundamental building blocks of nucleic acid can also be used for capping inorganic NCs, as shown in Figure . In particular, the nucleotide triphosphates (NTP) as the triphosphorylated versions of nucleosides are largely investigated for revealing the coordinating effect of nucleic acids on the growth of QDs. ,,, …”

Section: Aqueous Synthesis Of Semiconductor Ncsmentioning

confidence: 99%

Aqueous Based Semiconductor Nanocrystals

et al. 2016

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This review summarizes traditional and recent nonconventional, bioinspired, methods for the aqueous synthesis of colloidal semiconductor quantum dots (QDs). The basic chemistry concepts are critically emphasized at the very beginning as these are strongly correlated with the selection of ligands and the optimal formation of aqueous QDs and their more sophisticated structures. The synergies of biomimetic and biosynthetic methods that can combine biospecific reactivity with the robust and strong optical responses of QDs have also resulted in new approaches to the synthesis of the nanoparticles themselves. A related new avenue is the recent extension of QD synthesis to form nanoparticles endowed with chiral optical properties. The optical characteristics of QD materials and their advanced forms such as core/shell heterostructures, alloys, and doped QDs are discussed: from the design considerations of optical band gap tuning, the control and reduction of the impact of surface traps, the consideration of charge carrier processes that affect emission and energy and charge transfer, to the impact and influence of lattice strain. We also describe the considerable progress in some selected QD applications such as in bioimaging and theranostics. The review concludes with future strategies and identification of key challenges that still need to be resolved in reaching very attractive, scalable, yet versatile aqueous syntheses that may widen the scope of commercial applications for semiconductor nanocrystals.

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“…The associations between inflammation and tumor development have gained much interest in the past few decades [6]. Neutrophil to lymphocyte ratio (NLR), defined as the ratio of neutrophil to lymphocyte count, is a marker for evaluating the systemic potential balance between neutrophil-dependent pro-tumor inflammation and lymphocyte-associated anti-tumor immune response [7].…”

Section: Introductionmentioning

confidence: 99%

Prognostic Significance of Neutrophil-to-Lymphocyte Ratio in Ovarian Cancer: A Systematic Review and Meta-Analysis of Observational Studies

Huang

Zhou

Zeng

et al. 2017

Cell Physiol Biochem

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Background and Aims: Published data on the prognostic role of neutrophil-to-lymphocyte ratio (NLR) in ovarian cancer are controversial. We conducted this meta-analysis to obtain a more accurate assessment of prognostic significance of NLR in ovarian cancer. Materials and Methods: We conducted a systematic literature search using the electronic databases PubMed, Web of Science, and Embase up to May 2016. Hazard ratio (HR) and odd ratio (OR) with 95% confidence interval (95% CI) were calculated. Subgroup analyses were carried out to explore the source of heterogeneity. Statistical analysis was performed using Stata 10.0. Results: A total of 12 studies, consisting of 3,854 patients, which met our criterion were selected in this meta-analysis. Our pooled results showed that high pre-treatment NLR level was significantly associated with poorer overall survival (OS) (HR: 1.69, 95% CI 1.29-2.22) and shorter progression free survival (PFS) (HR 1.63, 95% CI 1.27–2.09). Additionally, increased NLR was also significantly correlated with advanced FIGO stage (OR 2.32, 95% CI1.79-3.00), higher serum level of CA-125 (OR 3.33, 95% CI 2.43-4.58), more extensive ascites (OR 3.54, 95% CI 2.31-5.42) as well as less chemotheraputic response (OR 0.53, 95% CI 0.40-0.70). The findings from most of subgroup meta-analyses were consistent with those from the overall meta-analyses. Conclusions: Elevated pre-treatment NLR could served as a predicative factor of poor prognosis for ovarian cancer patients.

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Photophysics and Photocatalytic Properties of Cd(OH)2-Coated Q-CdS Clusters in the Presence of Guanine and Related Compounds

Cited by 13 publications

References 32 publications

Photophysical Properties of Biologically Compatible CdSe Quantum Dot Structures

Photophysical Properties of Biologically Compatible CdSe Quantum Dot Structures

Aqueous Based Semiconductor Nanocrystals

Prognostic Significance of Neutrophil-to-Lymphocyte Ratio in Ovarian Cancer: A Systematic Review and Meta-Analysis of Observational Studies

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