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11.
Combinatorial Probes for High‐Throughput Electrochemical Analysis of Circulating Nucleic Acids in Clinical Samples 下载免费PDF全文
Dr. Jagotamoy Das Dr. Ivaylo Ivanov Dr. Tina S. Safaei Prof. Edward H. Sargent Prof. Shana O. Kelley 《Angewandte Chemie (International ed. in English)》2018,57(14):3711-3716
The analysis of circulating tumour nucleic acids (ctNAs) provides a minimally invasive way to assess the mutational spectrum of a tumour. However, effective and practical methods for analyzing this emerging class of markers are lacking. Analysis of ctNAs using a sensor‐based approach has notable challenges, as it is vital to differentiate nucleic acids from normal cells from mutation‐bearing sequences emerging from tumours. Moreover, many genes related to cancer have dozens of different mutations. Herein, we report an electrochemical approach that directly detects genes with mutations in patient serum by using combinatorial probes (CPs). The CPs enable detection of all of the mutant alleles derived from the same part of the gene. As a proof of concept, we analyze mutations of the EGFR gene, which has more than 40 clinically relevant alterations that include deletions, insertions, and point mutations. Our CP‐based approach accurately detects mutant sequences directly in patient serum. 相似文献
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Zhao X Gorelikov I Musikhin S Cauchi S Sukhovatkin V Sargent EH Kumacheva E 《Langmuir : the ACS journal of surfaces and colloids》2005,21(3):1086-1090
Thiol-capped water-soluble PbS nanocrystals (NCs) stabilized with 1-thioglycerol, dithioglycerol, or a mixture of 1-thioglycerol/dithioglycerol (TGL/DTG) were prepared via one-stage synthesis at room temperature. We found that NCs stabilized with a TGL/DTG mixture show efficient and stable infrared photoluminescence centered in the second "biological window" (1050-1200 nm). Under optimized conditions, full width at half-maximum of the PL emission peak was from 70 to 100 nm. PbS NCs were stable to precipitation and aggregation for the time period from 2 to 3 months when stored in the dark under room temperature. Room-temperature photoluminescence quantum efficiency of NCs was from 7 to 10%. When NCs were stored at 37 degrees C, their PL emission red-shifted, consistent with the NC growth. 相似文献
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Anita Sargent Thomas Loi Susannah Gal Omowunmi A. Sadik 《Journal of Electroanalytical Chemistry》1999,470(2):122
The modification of conducting polymer electrodes with antibodies (i.e. proteins) by means of electrochemical polymerization is a simple step that can be used to develop an immunological sensor. However, the electrochemical processes involved leading to the generation of analytical signals by the sensor have not been fully investigated. In this work, we report on the characterization of the interaction between an antigen, human serum albumin (HSA) and an antibody-immobilized polypyrrole electrode (such as anti-HSA) using cyclic voltammetry (CV) and impedance spectroscopy. This interaction was monitored using electrochemical impedance spectroscopy at three different potentials. The potentials correspond to the three redox states of the electroconducting polymer (i.e. reduced, doped and overoxidized states). Evidence from the CV experiments confirmed that there was a shift in the potential, which was found to be proportional to the concentration. Both the CV and the impedance experiments indicated that this potential-dependent shift could be attributed to antibody–antigen (Ab–Ag) binding. 相似文献
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Recent research into the unobstructed propagation of motorway noise has provided further information on ground absorption. This Note takes this information into account in making new proposals for the effect of the ground on the prediction of noise from motorways. 相似文献
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Murray Sargent 《Optics Communications》1977,20(2):298-302
Saturated absorption of infrared radiation by p-doped Ge is treated theoretically, predicting that both the saturation intensity and the width of the probe-saturator spectrum oscillate as functions of the saturator photon energy, ?ω. The maxima occur for ?ω = n?ωLO, where n is an integer and ?ωLO is the zone-center LO phonon energy. The results may a lso provide the closest measurement of hole cascade relaxation times to date. The oscillations depend on theoretical estimates that the LO phonon emissions occur substantially more rapidly than other decay processes. Hence failure to observe the oscillations would belie these estimates. 相似文献
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Christine?BreinerEmail author Ailana?Fraser Lan-Hsuan?Huang Chikako?Mese Pam?Sargent Yingying?Zhang 《Calculus of Variations and Partial Differential Equations》2018,57(1):12
We determine regularity results for energy minimizing maps from an n-dimensional Riemannian polyhedral complex X into a CAT(1) space. Provided that the metric on X is Lipschitz regular, we prove Hölder regularity with Hölder constant and exponent dependent on the total energy of the map and the metric on the domain. Moreover, at points away from the \((n-2)\)-skeleton, we improve the regularity to locally Lipschitz. Finally, for points \(x \in X^{(k)}\) with \(k \le n-2\), we demonstrate that the Hölder exponent depends on geometric and combinatorial data of the link of \(x \in X\). 相似文献
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Libing Zhang Zongjie Wang Jagotamoy Das Mahmoud Labib Sharif Ahmed Edward H. Sargent Shana O. Kelley 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(41):14661-14665
In living systems, interfacial molecular interactions control many biological processes. New stimuli‐responsive strategies are desired to provide versatile model systems that can regulate cell behavior in vitro. Described here are potential‐responsive surfaces that control cell adhesion and release as well as stem cell differentiation. Cell adhesion can be modulated dynamically by applying negative and positive potentials to surfaces functionalized with tailored monolayers. This process alters cell morphology and ultimately controls behavior and the fate of the cells. Cells can be detached from the electrode surface as intact clusters with different geometries using electrochemical potentials. Importantly, morphological changes during adhesion guide stem cell differentiation. The higher accessibility of the peptide under a positive applied potential causes phenotypic changes in the cells that are hallmarks of osteogenesis, whereas lower accessibility of the peptide promoted by negative potentials leads to adipogenesis. 相似文献
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Sibert JW Forshee PB Hundt GR Sargent AL Bott SG Lynch V 《Inorganic chemistry》2007,46(25):10913-10925
Two series of isomeric, redox-responsive azacrown ethers based on ortho- and para-phenylenediamine (Wurster's crowns) have been synthesized and their properties explored through 13C NMR spectroscopy, electrospray ionization mass spectrometry, cyclic voltammetry, and X-ray crystallography. These crowns display strong affinity for alkali metal cations while maintaining comparable selectivity profiles to the parent crown ethers from which they are derived. Like Wurster's reagent (N,N,N',N'-tetramethyl-p-phenylenediamine or para-TMPD), the para-Wurster's crowns undergo two reversible one-electron oxidations. The integrity of the alkali metal ion complexes is maintained in the neutral and singly oxidized ligand states but not after removal of two electrons. In contrast, the oxidation of ortho-Wurster's crowns is scan rate dependent, occurring at potentials substantially higher than their para counterparts, with their complexes oxidizing irreversibly. X-ray crystal structures of representative complexes show, in all cases, participation of the redox-active phenylenediamine subunits in complex formation via direct bonding to the guest cation. 相似文献
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