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1.
The electroporation microarray is a useful tool for high-throughput analysis of gene functions. However, transfection efficiency
is greatly impaired by storage of the microarrays, due to water evaporation from arrayed nucleotides. In this study, we aimed
at evaluating the effect of saccharides and sugar alcohols, added to the solution of the plasmid DNA or small interfering
RNA (siRNA). Microarrays loaded with plasmids and siRNAs were prepared with various polyols including sugars and sugar alcohols.
After storage of these microarrays at different temperatures for various time periods, transfection efficiency was evaluated
using human embryonic kidney cells. In the case of plasmid-loaded microarrays, addition of monosaccharides (glucose, fructose),
disaccharides (trehalose, sucrose), and trisaccharide (raffinose) served to retain transfection efficiency at a reasonably
high level after storage at −20 °C. The observed effects may be because moisture retention serves to maintain the solubility
of DNA. In contrast, polysaccharide (dextran) and sugar alcohol (glycerol) had insignificant effects on retention of transfection
efficiency. On the other hand, addition of saccharides and sugar alcohols had insignificant effects on the transfection of
siRNA after storage of a microarray at 25 °C for 7 days, presumably due to the intrinsically-high solubility of siRNA which
consists of short nucleotides.
Figure (PPTX 3.80 MB)
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
2.
Nora Graf Thomas Gross Thomas Wirth Wilfried Weigel Wolfgang E. S. Unger 《Analytical and bioanalytical chemistry》2009,393(8):1907-1912
The chemical composition of the functional surfaces of substrates used for microarrays is one of the important parameters
that determine the quality of a microarray experiment. In addition to the commonly used contact angle measurements to determine
the wettability of functionalized supports, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry
(ToF-SIMS) are more specific methods to elucidate details about the chemical surface constitution. XPS yields information
about the atomic composition of the surface, whereas from ToF-SIMS, information on the molecular species on the surface can
be concluded. Applied on printed DNA microarrays, both techniques provide impressive chemical images down to the micrometer
scale and can be utilized for label-free spot detection and characterization. Detailed information about the chemical constitution
of single spots of microarrays can be obtained by high-resolution XPS imaging.
Figure Eye-catching image for the graphical online abstract 相似文献
3.
Digital bioanalysis 总被引:3,自引:1,他引:2
Digital microfluidics has recently emerged as a new paradigm in the world of lab-on-a-chip technology. A wide variety of bioanalyses
have been successfully implemented in this format. This paper reviews the various techniques that have been adapted to digital
microfluidic systems, and the current state of the field.
Figure A multiplexed digital microfluidic device. Six analytical platforms are wired in series, allowing multiple independent analyses
to be performed simultaneously from a single set of controls. 相似文献
4.
Sergi M Bafile E Compagnone D Curini R D'Ascenzo G Romolo FS 《Analytical and bioanalytical chemistry》2009,393(2):709-718
An analytical procedure for the simultaneous determination in human plasma and oral fluids of several illicit drugs belonging
to different chemical and toxicological classes is presented. Amphetamine, methamphetamine, morphine, 6-monoacetylmorphine,
methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethamphetamine, cocaine, benzoylecgonine, tetrahydrocannabinol,
carboxytetrahydrocannabinol, ketamine, and phencyclidine have been quantified in real samples using a very rapid sample treatment,
basically a protein precipitation. The quantitative analysis was performed by liquid chromatography–tandem mass spectrometry
and has been fully validated. All the analytes were detected in positive ionization mode using a TurboIonSpray source, except
carboxytetrahydrocannabinol, which was detected in negative ionization mode. The use of a diverter valve between the column
and the mass spectrometer allows the preservation of the ion source performances for high-throughput analysis.
Figure Diverter system 相似文献
5.
Pérez Pavón JL García Pinto C Guerrero Peña A Moreno Cordero B 《Analytical and bioanalytical chemistry》2008,391(2):599-607
In the present work we report the results obtained with a methodology based on direct coupling of a headspace generator to
a mass spectrometer for the identification of different types of petroleum crudes in polluted soils. With no prior treatment,
the samples are subjected to the headspace generation process and the volatiles generated are introduced directly into the
mass spectrometer, thereby obtaining a fingerprint of volatiles in the sample analysed. The mass spectrum corresponding to
the mass/charge ratios (m/z) contains the information related to the composition of the headspace and is used as the analytical signal for the characterization
of the samples. The signals obtained for the different samples were treated by chemometric techniques to obtain the desired
information. The main advantage of the proposed methodology is that no prior chromatographic separation and no sample manipulation
are required. The method is rapid, simple and, in view of the results, highly promising for the implementation of a new approach
for oil spill identification in soils.
Figure PCA score plots illustrate clear discrimination of types of crude oil in polluted soil samples (e.g. results are shown for
vertisol) 相似文献
6.
Veronica M. T. Lattanzio Michele Solfrizzo Angelo Visconti 《Analytical and bioanalytical chemistry》2009,395(5):1325-1334
The selective enzymatic deacetylation of T-2 toxin to give HT-2 toxin has been investigated in aqueous crude extracts of different
cereals and exploited to develop an analytical method for the determination of the sum of T-2 and HT-2 toxins. The method
has been validated for the analysis of total T-2 and HT-2 toxins in maize, wheat, and oats, showing recoveries from 72 to
97% for maize, from 67 to 84% for wheat, and from 61% to 87% for oats, at spiking levels of 20–400 μg/kg, with relative standard
deviation lower than 10%. Liquid chromatography-tandem mass spectrometry was used for quantitative toxin determination. The
potential biological role of this enzymatic conversion and its perspectives for application in the development of antibody-based
analytical techniques are discussed.
相似文献
7.
Amino acids are important targets for metabolic profiling. For decades, amino acid analysis has been accomplished by either
cation-exchange or reversed-phase liquid chromatography coupled to UV absorbance or fluorescence detection of pre-column or
post-column-derivatized amino acids. Recent years have seen great progress in the development of direct-infusion or hyphenated
mass spectrometry in the analysis of free amino acids in physiological fluids, because mass spectrometry not only matches
optical detection in sensitivity, but also offers superior selectivity. The advent of cryo-probes has also brought NMR spectroscopy
within the detection limits required for the analysis of free amino acids. But there is still room for further improvement,
including expansion of the analyte spectrum, reduction of sample preparation and analysis time, automation, and synthesis
of affordable isotope standards.
Figure Fully automated gas chromatography-mass spectrometry analysis of amino acids. 相似文献
8.
Microfluidics offers an ideal platform to integrate cell-based assays with electric measurements. The technological advances
in microfluidics, microelectronics, electrochemistry, and electrophysiology have greatly inspired the development of microfluidic/electric
devices that work with a low number of cells or single cells. The applications of these microfluidic systems range from the
detecting of cell culture density to the probing of cellular functions at the single-cell level. In this review, we introduce
the recent advances in the electric analysis of cells on a microfluidic platform, specifically related to the quantification
and monitoring of cells in static solution, on-chip patch-clamp measurement, and examination of flowing cells. We also point
out future directions and challenges in this field.
Figure Different microfluidic devices applied to electrical analysis of cells 相似文献
9.
Playing tag with quantitative proteomics 总被引:1,自引:0,他引:1
There is steady need for new proteomic strategies on quantitative measurements that provide essential components for detailing
dynamic changes in many cellular functions and processes. Stable isotope labeling is a rapidly evolving field, which can be
used either after protein extraction with chemical labeling, or in cell culture with metabolic incorporation. In this review,
we explore the most frequently utilized quantitation techniques with particular attention paid to chemical labeling using
different isotopic tags, including a recent labeling strategy—soluble polymer-based isotopic labeling (SoPIL)—that achieves
efficient labeling in homogeneous conditions. Special care should be devoted to the selection of appropriate quantitation
approaches according to the needs of the sample and overall experimental design. We evaluate recent advances in quantitative
proteomics using stable isotope labeling and their applications to current insightful biological inquiries.
Figure Chemical modules of isotopic tags for quantitative proteomics. 相似文献
10.
Hinrichs K Gensch M Esser N Schade U Rappich J Kröning S Portwich M Volkmer R 《Analytical and bioanalytical chemistry》2007,387(5):1823-1829
The standard methods currently used to read out microarrays are fluorescent and chemiluminesent imaging techniques. These
methods require labeling of a component with a marker and, usually, only the concentration of the marker molecule is detected.
A label-free imaging method that also enables quantitative spectroscopic analysis of the composition and component interaction
would be of great advantage. In this article it is shown for the first time that IR mapping ellipsometry enables label-free
imaging of a biochip before and after incubation with peptide solution. The measurements prove that IR ellipsometry is a sensitive
tool for laterally resolved identification of the different materials and determination of the composition of a biochip. The
lateral resolution required was achieved by using radiation from an infrared synchrotron beamline.
相似文献
11.
Bertolini A Carelli G Francesconi F Francesconi M Marchesini L Marsili P Sorrentino F Cristoforetti G Legnaioli S Palleschi V Pardini L Salvetti A 《Analytical and bioanalytical chemistry》2006,385(2):240-247
Laser-induced breakdown spectroscopy (LIBS) is a promising technique for in situ elemental analysis. A new mobile instrument
for LIBS analysis, developed in a collaboration between Marwan Technology s.r.l. and the Applied Laser Spectroscopy Laboratory
in Pisa, is presented, and some applications of it and results from it are outlined. The innovative experimental set-up, based
on the use of two suitably retarded laser pulses and a standardless analysis procedure, which overcomes problems related to
matrix effects, greatly improves the potential of this technique for accurate quantitative analysis.
相似文献
12.
Stratis-Cullum DN Griffin GD Mobley J Vo-Dinh T 《Analytical and bioanalytical chemistry》2008,391(5):1655-1660
This paper reports the first intensified biochip system for chemiluminescence detection and the feasibility of using this
system for the analysis of biological warfare agents is demonstrated. An enzyme-linked immunosorbent assay targeting Bacillus globigii spores, a surrogate species for Bacillus anthracis, using a chemiluminescent alkaline phosphatase substrate is combined with a compact intensified biochip detection system.
The enzymatic amplification was found to be an attractive method for detection of low spore concentrations when combined with
the intensified biochip device. This system was capable of detecting approximately 1 × 105
Bacillus globigii spores. Moreover, the chemiluminescence method, combined with the self-contained biochip design, allows for a simple, compact
system that does not require laser excitation and is readily adaptable to field use.
Figure Schematic diagram of the miniature biochip detection system 相似文献
13.
Naoya Kishikawa Nobuhiro Ohkubo Kaname Ohyama Kenichiro Nakashima Naotaka Kuroda 《Analytical and bioanalytical chemistry》2009,393(4):1337-1343
A sensitive and selective chemiluminescence assay for the determination of quinones was developed. The method was based on
generation of reactive oxygen species through the redox reaction between quinone and dithiothreitol as reductant, and then
the generated reactive oxygen was detected by luminol chemiluminescence. The chemiluminescence was intense, long-lived, and
proportional to quinone concentration. It is concluded that superoxide anion was involved in the proposed chemiluminescence
reaction because the chemiluminescence intensity was decreased only in the presence of superoxide dismutase. Among the tested
quinones, the chemiluminescence was observed from 9,10-phenanthrenequinone, 1,2-naphthoquinone, and 1,4-naphthoquinone, whereas
it was not observed from 9,10-anthraquinone and 1,4-benzoquinone. The chemiluminescence property was greatly different according
to the structure of quinones. The chemiluminescence was also observed for biologically important quinones such as ubiquinone.
Therefore, a simple and rapid assay for ubiquinone in pharmaceutical preparation was developed based on the proposed chemiluminescence
reaction. The detection limit (blank + 3SD) of ubiquinone was 0.05 μM (9 ng/assay) with an analysis time of 30 s per sample.
The developed assay allowed the direct determination of ubiquinone in pharmaceutical preparation without any purification
procedure.
Figure Chemiluminescence generated through the redox cycle of quinone 相似文献
14.
SPME in environmental analysis 总被引:1,自引:0,他引:1
Recent advances in the use of solid-phase microextraction (SPME) in environmental analysis, including fiber coatings, derivatization
techniques, and in-tube SPME, are reviewed in this article. Several calibration methods for SPME, including traditional calibration
methods, the equilibrium extraction method, the exhaustive extraction method, and several diffusion-based calibration methods,
are presented. Recent developed SPME devices for on-site sampling and several applications of SPME in environmental analysis
are also introduced.
相似文献
15.
Morais S Tamarit-López J Carrascosa J Puchades R Maquieira A 《Analytical and bioanalytical chemistry》2008,391(8):2837-2844
A sensitive and versatile methodology involving recordable compact disks as molecular screening surfaces and a standard optical
CD/DVD drive as detector, is reported. Quantitative immunoanalysis, in microarray format, of a cancer marker (alpha-fetoprotein,
AFP) and a selective herbicide (atrazine) on four types of audio-video disc was conducted. Enzyme or gold nanoparticle-labeled
antibodies were used as tracers, forming a precipitate on the sensing disk surface. The principle of disk reading is based
on capture of analog signals with the disk drive that were proportional to the darkness of the immunoreaction product. Detection
limits for AFP (8.0 μg L−1) and for atrazine (0.04 μg L−1) were under the threshold needed to detect nonseminomatous testicular cancer, and below the maximum E.U. residue limit for
drinking water, respectively. The described methodology improves the previous developments using CDs and highlights the enormous
potential of immunoassay methods using standard audio–video disk surfaces in combination with the CD/DVD drive for clinical
analysis, drug discovery, or high-throughput multiresidue screening applications.
Figure
Eye-catching image The analytical potential of commercial audio–video discs as molecular screening surfaces in combination with use of a standard
CD/DVD drive as detector for quantitative immunoanalysis of a cancer marker and agrochemical residues is demonstrated. 相似文献
16.
Stir bar sorptive extraction in combination with thermal desorption coupled online to capillary gas chromatography–mass spectrometry
was applied to investigate volatile and semivolatile fractions in two waste leachate samples: old and fresh ones. The present
study helps to improve our knowledge of waste leachate organic composition. The aim is to then make use of this knowledge
afterwards in order to generate more reliable and specific treatment processes for waste leachates and thus to respect the
environmental statute law regarding their rejection. The volatile and semivolatile compounds appeared to be mainly anthropogenic
in origin. Moreover, lactic acid and cyclic octaatomic sulfur could potentially be used as microbiological activity indicators,
since they occur during organic matter degradation processes within waste leachates.
Figure TDU-CGC-MS analytical equipment 相似文献
17.
Tragoulias SS Obeid PJ Tataridis IE Christopoulos TK 《Analytical and bioanalytical chemistry》2008,390(6):1563-1573
Microarray technology covers the urgent need to exploit the accumulated genetic information from large-scale sequencing projects
and facilitate investigations on a genome-wide scale. Although most applications focus on DNA microarrays, the technology
has expanded to microarrays of proteins, peptides, carbohydrates, and small molecules aiming either at detection/quantification
of biomolecules or investigation of biomolecular interactions in a massively parallel manner. Microarray experiments require
two specialized instruments: An arrayer (or printer), for construction of microarrays, and a readout instrument (scanner).
We have designed, constructed, and characterized the first integrated microarray system (IMAS) that combines the functions
of a microarrayer and a three-laser confocal fluorescence scanner into a single instrument and provides excellent flexibility
for the researcher. The three-axis robotic system that moves the printing head carrying multiple pins for arraying is also
used for moving the microarray slide in front of a stationary optical system during scanning. Since the translation stages
are the most expensive and crucial components of microarray printers and scanners, the proposed design reduces considerably
the cost of the instrument and enhances remarkably its operative flexibility. Experiments were carried out at resolutions
of 2.5, 5, 10, and 20 μm. The scanner detects 0.128 nmol L−1 carboxyfluorescein (spots with diameters of 70 μm) corresponding to 1.8 molecules μm−2. The linear range extends over 3.5 orders of magnitude (R
2 = 0.997) and the dynamic range covers almost five orders of magnitude. DNA microarray model experiments were carried out,
including staining with SYBR Green I and hybridization with oligonucleotides labeled with the fluorescent dyes Alexa 488,
Alexa 594, and Alexa 633.
Figure Lay-out of the home-built integrated microarray system (IMAS). For the first time, the functions of a microarrayer (printer)
and a three-laser confocal fluorescence scanner are combined into a single instrument. The three-axis robotic system that
moves the printing head for arraying is also used to move the microarray slide in front of a stationary optical system during
scanning.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
Yveline Henchoz Bruno Bard Davy Guillarme Pierre-Alain Carrupt Jean-Luc Veuthey Sophie Martel 《Analytical and bioanalytical chemistry》2009,394(3):707-729
The measurement of physicochemical properties at an early phase of drug discovery and development is crucial to reduce attrition
rates due to poor biopharmaceutical properties. Among these properties, ionization, lipophilicity, solubility and permeability
are mandatory to predict the pharmacokinetic behavior of NCEs (new chemical entities). Due to the high number of NCEs, the
analytical tools used to measure these properties are automated and progressively adapted to high-throughput technologies.
The present review is dedicated to experimental methods applied in the early drug discovery process for the determination
of solubility, ionization constants, lipophilicity and permeability of small molecules. The principles and experimental conditions
of the different methods are described, and important enhancements in terms of throughput are highlighted.
Figure Scheme of the Drug Research Process. 相似文献
19.
Determination of antimicrobial residues and metabolites in the aquatic environment by liquid chromatography tandem mass spectrometry 总被引:2,自引:0,他引:2
Antimicrobials are used in large quantities in human and veterinary medicine. Their environmental occurrence is of particular
concern due to the potential spread and maintenance of bacterial resistance. After intake by the organisms, the unchanged
drug and its metabolized forms are excreted and enter wastewater treatment plants where they are mostly incompletely eliminated,
and are therefore eventually released into the aquatic environment. The reliable detection of several antimicrobials in different
environmental aqueous compartments is the result of great improvements achieved in analytical chemistry. This article provides
an overview of the more outstanding analytical methods based on liquid chromatography tandem mass spectrometry, developed
and applied to determine antimicrobial residues and metabolites present in surface, waste, and ground waters.
相似文献
20.
Applications of microelectromechanical systems (MEMS) technology are widespread in both industrial and research fields providing
miniaturized smart tools. In this review, we focus on MEMS applications aiming at manipulations and characterization of biomaterials
at the single molecule level. Four topics are discussed in detail to show the advantages and impact of MEMS tools for biomolecular
manipulations. They include the microthermodevice for rapid temperature alternation in real-time microscopic observation,
a microchannel with microelectrodes for isolating and immobilizing a DNA molecule, and microtweezers to manipulate a bundle
of DNA molecules directly for analyzing its conductivity. The feasibilities of each device have been shown by conducting specific
biological experiments. Therefore, the development of MEMS devices for single molecule analysis holds promise to overcome
the disadvantages of the conventional technique for biological experiments and acts as a powerful strategy in molecular biology.
Figure Towards single bio molecular handling and characterization by MEMS 相似文献