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1.
The use of polymers in microchip fabrication affords new opportunities for the development of powerful, miniaturized separation
techniques. One method in particular, the use of phase-changing sacrificial layers, allows for simplified designs and many
additional features to the now standard fabrication of microchips. With the possibility of adding a third dimension to the
design of separation devices, various means of enhancing analysis now become possible. The application of phase-changing sacrificial
layers in microchip analysis systems is discussed, both in terms of current uses and future possibilities.
Figure Phase-changing sacrificial materials enable multilayer microfluidic device layouts 相似文献
2.
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
3.
Martinez Vazquez R Osellame R Cretich M Chiari M Dongre C Hoekstra HJ Pollnau M van den Vlekkert H Ramponi R Cerullo G 《Analytical and bioanalytical chemistry》2009,393(4):1209-1216
We use direct femtosecond laser writing to integrate optical waveguides into a commercial fused silica capillary electrophoresis
chip. High-quality waveguides crossing the microfluidic channels are fabricated and used to optically address, with high spatial
selectivity, their content. Fluorescence from the optically excited volume is efficiently collected at a 90° angle by a high
numerical aperture fiber, resulting in a highly compact and portable device. To test the platform we performed electrophoresis
and detection of a 23-mer oligonucleotide plug. Our approach is quite powerful because it allows the integration of photonic
functionalities, by simple post-processing, into commercial LOCs fabricated with standard techniques.
Figure Femtosecond laser written waveguides can selectively excite fluorescence in a microfluidic channel of a commercial lab-on-a-chip.
A compact scheme for on-chip detection by laser induced fluorescence is applied to capillary electrophoresis of a 23-mer Cy3-labeled
oligonucleotide 相似文献
4.
Schumann CA Dörrenhaus A Franzke J Lampen P Dittrich PS Manz A Roos PH 《Analytical and bioanalytical chemistry》2008,392(6):1159-1166
To understand molecular networking at the cellular level, analyses of processes and effects at the single-cell level are most
appropriate. Usual biochemical or molecular biological analyses are based on integrated signals of numerous cells which differ,
however, in their expression and activity profiles. Here we show that it is possible to determine different types of properties
of individual cells by means of a specifically designed microfluidic device. As part of investigations to characterize the
human urothelial cell line 5637 as a potential model system for studies of toxic and carcinogenic effects on urothelial cells,
we use this cell line to assign cytochrome P450 activity, and expression of the enzymes involved, to individual cells. It
is shown that the cell population is very heterogeneous with respect to the extent and kinetics of CYP1A1-dependent ethoxyresorufin
O-deethylase (EROD). This is also true for the cells’ CYP1A1 protein content. With some exceptions, the EROD activity largely
coincides with the presence of CYP1A1 protein in the cells. The results obtained with the microfluidic device are promising
and open up new perspectives with regard to multi-property determinations in individual cells and to studies focusing on the
biochemical and molecular heterogeneity of cells.
Figure Formation of fluorescent resorufin from ethoxyresorufin by cytochrome P450 activity in urothelial cells attached within the
chamber of a microfluidic device 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.
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
7.
Because variability exists within populations of cells, single-cell analysis has become increasingly important for probing
complex cellular environments. Capillary electrophoresis (CE) is an excellent technique for identifying and quantifying the
contents of single cells owing to its small volume requirements and fast, efficient separations with highly sensitive detection.
Recent progress in both whole-cell and subcellular sampling has allowed researchers to study cellular function in the areas
of neuroscience, oncology, enzymology, immunology, and gene expression.
相似文献
8.
Eric B. Kalman Olivier Sudre Ivan Vlassiouk Zuzanna S. Siwy 《Analytical and bioanalytical chemistry》2009,394(2):413-419
Control of ionic transport through nanoporous systems is a topic of scientific interest for the ability to create new devices
that are applicable for ions and molecules in water solutions. We show the preparation of an ionic transistor based on single
conical nanopores in polymer films with an insulated gold thin film “gate.” By changing the electric potential applied to
the “gate,” the current through the device can be changed from the rectifying behavior of a typical conical nanopore to the
almost linear behavior seen in cylindrical nanopores. The mechanism for this change in transport behavior is thought to be
the enhancement of concentration polarization induced by the gate.
Figure
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
Recent developments in solid-phase microextraction 总被引:2,自引:0,他引:2
Risticevic S Niri VH Vuckovic D Pawliszyn J 《Analytical and bioanalytical chemistry》2009,393(3):781-795
The main objective of this review is to describe the recent developments in solid-phase microextraction technology in food,
environmental and bioanalytical chemistry applications. We briefly introduce the historical perspective on the very early
work associated with the development of theoretical principles of SPME, but particular emphasis is placed on the more recent
developments in the area of automation, high-throughput analysis, SPME method optimization approaches and construction of
new SPME devices and their applications. The area of SPME automation for both GC and LC applications is particularly addressed
in this review, as the most recent developments in this field have allowed the use of this technology for high-throughput
applications. The development of new autosamplers with SPME compatibility and new-generation metal fibre assemblies has enhanced
sample throughput for SPME-GC applications, the latter being attributed to the possibility of using the same fibre for several
hundred extraction/injection cycles. For LC applications, high-throughput analysis (>1,000 samples per day) can be achieved
for the first time with a multi-SPME autosampler which uses multi-well plate technology and allows SPME sample preparation
of up to 96 samples in parallel. The development and evolution of new SPME devices such as needle trap, thin-film microextraction
and cold-fibre headspace SPME have offered significant improvements in performance characteristics compared with the conventional
fibre-SPME arrangement.
Figure Photo of a high-throughput multi-fibre SPME PAS autosampler 相似文献
10.
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
11.
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
12.
The paper reviews the state-of-art for micro optical fluidic systems (MOFS), or optofluidics, which employs optics and fluidics
in a microsystem environment to perform novel functionalities and in-depth analysis in the biophysical area. Various topics,
which include the introduction of MOFS in biomedical engineering, the implementation of near-field optics and also the applications
of MOFS to biophysical studies, are discussed. Different optical detection techniques, such as evanescent wave, surface plasmon
resonance, surface enhanced Raman scattering, resonators and transistors, have been studied extensively and integrated into
MOFS. In addition, MOFS also provides a platform for various studies of cell biophysics, such as cell mass determination and
cell Young’s modulus measurement.
Figure Cell encapsulation and trapping for refractive index measurement in MOFS 相似文献
13.
Bai LP Cai Z Zhao ZZ Nakatani K Jiang ZH 《Analytical and bioanalytical chemistry》2008,392(4):709-716
Spectrofluorometric titration, electrospray ionization time-of-flight mass spectrometric and UV melting methods were employed
to study the binding of chelerythrine and sanguinarine to bulged DNA. The results showed that both alkaloids bind specifically
to single pyrimidine (C, T) bulge sites. The ability of sanguinarine to bind to both regular and bulged hairpins was found
to be stronger than that of chelerythrine, but the binding selectivity of chelerythrine toward single-base bulges was much
larger than that of sanguinarine.
Figure Association constants for chelerythrine and sanguinarine toward regular and single-base bulged hairpins obtained from fluorometric
analysis 相似文献
14.
Henares TG Mizutani F Sekizawa R Hisamoto H 《Analytical and bioanalytical chemistry》2008,391(7):2507-2512
Single-drop analysis of two different real sample solutions (2 μL) while simultaneously monitoring the activity of two sets
of ten different proteases on a single microfluidic device is presented. The device, called a capillary-assembled microchip
(CAs-CHIP), is fabricated by embedding square glass sensing capillaries (reagent-release capillaries, RRC) in the polydimethylsiloxane
(PDMS) lattice microchannel, and used for that purpose. First, the performance reliability was evaluated by measuring the
fluorescence response of twenty caspase-3-sensing capillaries on a single CAs-CHIP, and a relative standard deviation of 1.5–8.2
(% RSD, n = 5 or 10) was obtained. This suggests that precise multiplexed protease-activity sensing is possible by using a single CAs-CHIP
with multiple RRCs embedded. Then, using a single CAs-CHIP, real sample analysis of the activity of ten different caspases/proteases
in cervical cancer (HeLa) cell lysate treated and untreated with the cell-death-inducer drug, doxorubicin, was simultaneously
carried out, and a significant difference in enzyme activity between these two samples was observed. These results suggested
the usefulness of the CAs-CHIP in the field of drug discovery.
Figure Single drop analysis of two real sample solutions including various different proteases using a single microfluidic device
was achieved 相似文献
15.
Cellular microarrays for use with capillary-driven microfluidics 总被引:1,自引:0,他引:1
Lovchik R von Arx C Viviani A Delamarche E 《Analytical and bioanalytical chemistry》2008,390(3):801-808
We present a method for the facile arraying of cells on microstructured substrates which should be suitable for cellular assays
in autonomous microfluidic capillary systems (CSs). The CSs, which were designed and microfabricated in Si, have various microfluidic
functional elements including reaction chambers wherein cellular arrays are located. Two methods for arraying the cells were
explored. In the first method, a hydrophobic alkanethiol was microcontact-printed on the bottom surface of a microfluidic
reaction chamber. The subsequent adsorption of protein-repellent alkanethiols around the printed areas and the deposition
from solution of fibronectin (FN) on the hydrophobic areas resulted in an adhesive pattern for the attachment of living human
breast cancer cells. This method was limited by the formation of cellular clusters, which proved difficult to remove selectively.
The second method employed a poly(dimethylsiloxane) elastomer having oval recessed microstructures. The selective coating
of the inner walls of the ovals with FN and the blocking of the mesas around the ovals with bovine serum albumin (BSA) permitted
single or multiple cells to be arrayed depending on the size of the ovals. The possibility of sealing CSs with cells arrayed
on poly(dimethylsiloxane) may provide a versatile platform for high-throughput experimentation down to the single-cell level.
Figure The deposition of one or a few living cells in fibronectin-coated poly(dimethylsiloxane) microstructures results in cellular
arrays, which can be interfaced with capillary-driven microfluidics 相似文献
16.
Lee JO So HM Jeon EK Chang H Won K Kim YH 《Analytical and bioanalytical chemistry》2008,390(4):1023-1032
Recent advances in nanotechnology have enabled the development of nanoscale sensors that outperform conventional biosensors.
This review summarizes the nanoscale biosensors that use aptamers as molecular recognition elements. The advantages of aptamers
over antibodies as sensors are highlighted. These advantages are especially apparent with electrical sensors such as electrochemical
sensors or those using field-effect transistors.
Figure Feeling proteins with aptamer-functionalized carbon nanotubes 相似文献
17.
4,4′-methylenedianiline (DAPM) is the main building block for production of 4,4′-methylenediphenyldiisocyanate that has been
widely used in the manufacturing of polyurethane materials including medical devices. Although it was revealed that damage
to biliary epithelial cells of the liver and common bile duct occurred upon acute exposure to DAPM, the exact mechanism of
DAPM toxicity is not fully understood. Both phase I and II biotransformations of DAPM, some of which generate reactive intermediates,
are characterized in detail by liquid chromatography electrospray tandem mass spectrometry. The two most prominent metabolites
found in rat bile (M2 and M7) implicated glutathione, glucuronic acid, and glycine conjugations (phase II) following hydroxylation,
and N-oxidation (phase I). Their decomposition pathways, as evidenced by MS
n
experiments, have been elucidated in detail.
Figure Proposed fragmentation pathways of a DAPM metabolite 相似文献
18.
19.
Microarrays provide a powerful analytical tool for the simultaneous detection of multiple analytes in a single experiment.
The specific affinity reaction of nucleic acids (hybridization) and antibodies towards antigens is the most common bioanalytical
method for generating multiplexed quantitative results. Nucleic acid-based analysis is restricted to the detection of cells
and viruses. Antibodies are more universal biomolecular receptors that selectively bind small molecules such as pesticides,
small toxins, and pharmaceuticals and to biopolymers (e.g. toxins, allergens) and complex biological structures like bacterial
cells and viruses. By producing an appropriate antibody, the corresponding antigenic analyte can be detected on a multiplexed
immunoanalytical microarray. Food and water analysis along with clinical diagnostics constitute potential application fields
for multiplexed analysis. Diverse fluorescence, chemiluminescence, electrochemical, and label-free microarray readout systems
have been developed in the last decade. Some of them are constructed as flow-through microarrays by combination with a fluidic
system. Microarrays have the potential to become widely accepted as a system for analytical applications, provided that robust
and validated results on fully automated platforms are successfully generated. This review gives an overview of the current
research on microarrays with the focus on automated systems and quantitative multiplexed applications.
Figure MCR 3: A fully automated chemiluminescence microarray reader for analytical microarrays 相似文献
20.
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