scholarly journals FLUORESCENT PROPERTIES OF DOXYCYCLINE IN PRESENCE OF SILVER NANOCLUSTERS

2020 ◽  
Vol 64 (1) ◽  
pp. 34-40
Author(s):  
Tatyana D. Smirnova ◽  
Elens A. Zhelobitskaya ◽  
Tatyana G. Danilina ◽  
Natalya A. Simbireva
Keyword(s):  
Silver Nanoparticles ◽  
Energy Transfer ◽  
Excitation Energy ◽  
Surface Plasmon ◽  
Limit Of Detection ◽  
Silver Nanoclusters ◽  
Complexing Agent ◽  
Intramolecular Energy Transfer ◽  
Sensitized Fluorescence ◽  
Wide Range

The paper shows that in the presence of silver nanoparticles the efficiency of intramolecular energy transfer in the complex of europium with doxycycline increases. It is proved that sensitivity of determination increases and limit of detection of doxycycline decreases by the method of sensitized fluorescence. The justification of the observed effects is given. The amplification of the signal of sensitized fluorescence in the presence of silver nanoparticles (energy donor) is the result of resonant transfer of excitation energy between the nanoparticle and the antibiotic ion, which is implemented under conditions of overlapping of the local surface plasmon resonance spectrum and excitation of the doxycycline ligand located near the surface of the nanoparticle. As a result of exposure to the antibiotic external radiation source and the local field of the surface plasmon increases the efficiency of tetracycline excitation, which contributes to the effectiveness of intramolecular energy transfer in europium chelate with doxycycline, doubling the intensity and lifetime. Modification of the surface of silver nanoparticles by europium ions allows to reduce the distance between the surface of a nanoparticle and an antibiotic, to increase the intensity of the signal of sensitized fluorescence by more than 100 times. The role of the stabilizer of a non-chromophore-containing ligand, − citrateion, in the formation of the analytical signal lies in its participation in the formation of a multi-ligand Eu3+ complex on the surface of a nanoobject, which reduces the distance between the donor and the acceptor, as well as the additional removal of water molecules from the immediate environment of the complexing agent ion, suppressing the process of excitation energy dissipation. On the basis of the conducted researches the fluorimetric technique of definition of doxycycline in medicines is offered. It differs in a low limit of detection (6.0·10-9 M) and a wide range of the defined concentrations from 1.0·10-8 to 1.0·10-5 M.

Resonant excitation energy transfer from carbon dots to different sized silver nanoparticles

2016 ◽  
Vol 18 (41) ◽  
pp. 28911-28918 ◽  
Author(s):  
Roopali Prajapati ◽  
Arpan Bhattacharya ◽  
Tushar Kanti Mukherjee
Keyword(s):  
Silver Nanoparticles ◽  
Energy Transfer ◽  
Surface Energy ◽  
Excitation Energy ◽  
Carbon Dots ◽  
Excitation Energy Transfer ◽  
Photoluminescence Spectroscopy ◽  
Resonant Excitation ◽  
Ag Nps ◽  
Size Dependent

In the present study we have demonstrated the size-dependent resonant nanometal surface energy transfer (NSET) from carbon dots (CDs) to silver nanoparticles (Ag NPs) using photoluminescence spectroscopy.

scholarly journals Highly Sensitive Emission Sensor Based on Surface Plasmon Enhanced Energy Transfer between Gold Nanoclusters and Silver Nanoparticles

2009 ◽  
Vol 114 (2) ◽  
pp. 799-802 ◽  
Author(s):  
Chih-Wei Chen ◽  
Chun-Hsiung Wang ◽  
Chih-Ming Wei ◽  
Chun-Yi Hsieh ◽  
Yung-Ting Chen ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Energy Transfer ◽  
Surface Plasmon ◽  
Gold Nanoclusters ◽  
Highly Sensitive

scholarly journals De novo synthetic biliprotein design, assembly and excitation energy transfer

2018 ◽  
Vol 15 (141) ◽  
pp. 20180021 ◽  
Author(s):  
Joshua A. Mancini ◽  
Molly Sheehan ◽  
Goutham Kodali ◽  
Brian Y. Chow ◽  
Donald A. Bryant ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
De Novo ◽  
Excitation Energy Transfer ◽  
Fluorescence Yield ◽  
Conformational Restriction ◽  
Wide Range ◽  
Α Helix

Bilins are linear tetrapyrrole chromophores with a wide range of visible and near-visible light absorption and emission properties. These properties are tuned upon binding to natural proteins and exploited in photosynthetic light-harvesting and non-photosynthetic light-sensitive signalling. These pigmented proteins are now being manipulated to develop fluorescent experimental tools. To engineer the optical properties of bound bilins for specific applications more flexibly, we have used first principles of protein folding to design novel, stable and highly adaptable bilin-binding four-α-helix bundle protein frames, called maquettes, and explored the minimal requirements underlying covalent bilin ligation and conformational restriction responsible for the strong and variable absorption, fluorescence and excitation energy transfer of these proteins. Biliverdin, phycocyanobilin and phycoerythrobilin bind covalently to maquette Cys in vitro . A blue-shifted tripyrrole formed from maquette-bound phycocyanobilin displays a quantum yield of 26%. Although unrelated in fold and sequence to natural phycobiliproteins, bilin lyases nevertheless interact with maquettes during co-expression in Escherichia coli to improve the efficiency of bilin binding and influence bilin structure. Bilins bind in vitro and in vivo to Cys residues placed in loops, towards the amino end or in the middle of helices but bind poorly at the carboxyl end of helices. Bilin-binding efficiency and fluorescence yield are improved by Arg and Asp residues adjacent to the ligating Cys on the same helix and by His residues on adjacent helices.

Control of localized surface plasmon resonance energy in monolayer structures of gold and silver nanoparticles

2015 ◽  
Vol 17 (40) ◽  
pp. 27077-27081 ◽  
Author(s):  
Hiroki Yokota ◽  
Taichi Taniguchi ◽  
Taichi Watanabe ◽  
DaeGwi Kim
Keyword(s):  
Silver Nanoparticles ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Ag Nanoparticles ◽  
Localized Surface Plasmon Resonance ◽  
Resonance Energy ◽  
Localized Surface Plasmon ◽  
Gold And Silver Nanoparticles ◽  
Wide Range

The LSPR energy was successfully controlled in the wide range of 2.0–3.0 eV using Au and Ag nanoparticles.

Dependence of the Lifetime upon the Excitation Energy and Intramolecular Energy Transfer Rates: The5D0EuIIIEmission Case

2012 ◽  
Vol 18 (38) ◽  
pp. 12130-12139 ◽  
Author(s):  
Rute A. S. Ferreira ◽  
Mariela Nolasco ◽  
Ana C. Roma ◽  
Ricardo L. Longo ◽  
Oscar L. Malta ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Intramolecular Energy Transfer ◽  
Transfer Rates

Thymine Dimerization Induced by Oxidative DNA Lesions and Epigenetic Intermediates via Triplet-Triplet Energy Transfer

2020 ◽  
Author(s):  
Mauricio Lineros-Rosa ◽  
Antonio Francés-Monerris ◽  
Antonio Monari ◽  
Miguel Angél Miranda ◽  
Virginie Lhiaubet-Vallet
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Transient Absorption ◽  
Theoretical Calculations ◽  
Dna Lesions ◽  
Transient Absorption Spectroscopy ◽  
Triplet Energy ◽  
Pyrimidine Dimers ◽  
Triplet Energy Transfer ◽  
Dna Nucleobases

Interaction of nucleic acids with light is a scientific question of paramount relevance not only in the understanding of life functioning and evolution, but also in the insurgence of diseases such as malignant skin cancer and in the development of biomarkers and novel light-assisted therapeutic tools. This work shows that the UVA portion of sunlight, not absorbed by canonical DNA nucleobases, can be absorbed by 5-formyluracil (ForU) and 5-formylcytosine (ForC), two ubiquitous oxidative lesions and epigenetic intermediates present in living beings in natural conditions. We measure the strong propensity of these molecules to populate triplet excited states able to transfer the excitation energy to thymine-thymine dyads, inducing the formation of the highly toxic and mutagenic cyclobutane pyrimidine dimers (CPDs). By using steady-state and transient absorption spectroscopy, NMR, HPLC, and theoretical calculations, we quantify the differences in the triplet-triplet energy transfer mediated by ForU and ForC, revealing that the former is much more efficient in delivering the excitation energy and producing the CPD photoproduct. Although significantly slower than ForU, ForC is also able to harm DNA nucleobases and therefore this process has to be taken into account as a viable photosensitization mechanism. The present findings evidence a rich photochemistry crucial to understand DNA photodamage and of potential use in the development of biomarkers and non-conventional photodynamic therapy agents.

Validated Stability Indicating HPTLC Method for the Estimation of Amoxapine in Different Stress Conditions

2019 ◽  
Vol 15 (3) ◽  
pp. 273-279
Author(s):  
Shweta G. Rangari ◽  
Nishikant A. Raut ◽  
Pradip W. Dhore
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Degradation Products ◽  
Analysis Data ◽  
Peak Height ◽  
Good Resolution ◽  
Stability Indicating ◽  
Limit Of Quantitation ◽  
Wide Range ◽  
Hptlc Method

Background:The unstable and/or toxic degradation products may form due to degradation of drug which results into loss of therapeutic activity and lead to life threatening condition. Hence, it is important to establish the stability characteristics of drug in various conditions such as in temperature, light, oxidising agent and susceptibility across a wide range of pH values.Introduction:The aim of the proposed study was to develop simple, sensitive and economic stability indicating high performance thin layer chromatography (HPTLC) method for the quantification of Amoxapine in the presence of degradation products.Methods:Amoxapine and its degraded products were separated on precoated silica gel 60F254 TLC plates by using mobile phase comprising of methanol: toluene: ammonium acetate (6:3:1, v/v/v). The densitometric evaluation was carried out at 320 nm in reflectance/absorbance mode. The degradation products obtained as per ICH guidelines under acidic, basic and oxidative conditions have different Rf values 0.12, 0.26 and 0.6 indicating good resolution from each other and pure drug with Rf: 0.47. Amoxapine was found to be stable under neutral, thermal and photo conditions.Results:The method was validated as per ICH Q2 (R1) guidelines in terms of accuracy, precision, ruggedness, robustness and linearity. A good linear relationship between concentration and response (peak area and peak height) over the range of 80 ng/spot to 720 ng/spot was observed from regression analysis data showing correlation coefficient 0.991 and 0.994 for area and height, respectively. The limit of detection (LOD) and limit of quantitation (LOQ) for area were found to be 1.176 ng/mL and 3.565 ng/mL, whereas for height, 50.063 ng/mL and 151.707 ng/mL respectively.Conclusion:The statistical analysis confirmed the accuracy, precision and selectivity of the proposed method which can be effectively used for the analysis of amoxapine in the presence of degradation products.

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