共查询到20条相似文献,搜索用时 31 毫秒
1.
SangWook Lee Soyoun Kim Johan Malm Ok Chan Jeong Hans Lilja Thomas Laurell 《Analytica chimica acta》2013
Enriching the surface density of immobilized capture antibodies enhances the detection signal of antibody sandwich microarrays. In this study, we improved the detection sensitivity of our previously developed P-Si (porous silicon) antibody microarray by optimizing concentrations of the capturing antibody. We investigated immunoassays using a P-Si microarray at three different capture antibody (PSA – prostate specific antigen) concentrations, analyzing the influence of the antibody density on the assay detection sensitivity. The LOD (limit of detection) for PSA was 2.5 ng mL−1, 80 pg mL−1, and 800 fg mL−1 when arraying the PSA antibody, H117 at the concentration 15 μg mL−1, 35 μg mL−1, and 154 μg mL−1, respectively. We further investigated PSA spiked into human female serum in the range of 800 fg mL−1 to 500 ng mL−1. The microarray showed a LOD of 800 fg mL−1 and a dynamic range of 800 fg mL−1 to 80 ng mL−1 in serum spiked samples. 相似文献
2.
Rapid multiplexed analysis of microorganisms is important in water analysis to control bacterial contamination for health
and safety reasons. Direct quantification of bacteria by means of flow-through microarray immunoassays requires new analysis
strategies for optimising sensitivity and the analysis time. For bacteria and for particles, hydrodynamic forces and sedimentation
are the dominating effects for binding on surfaces in a flow-through system, whereas diffusion is insignificant. Therefore,
we have implemented a stop and flow technique for quantification of viable E. coli cells. The method, with alternation of resting volume elements and pumping the elements forward, was more effective than
continuous-flow approaches for analysis of bacteria. For quantification of viable E. coli cells, a chemiluminescence sandwich immunoassay test format was performed by means of antibody microarrays and flow-injection-based
microarray analysis. Antibodies, which served as selective capture molecules, were immobilised on polymer-modified glass surfaces
serving as microarray substrate. For the bacteria recognition step, a second detection antibody was used, forming a sandwich
immunoassay at each spot of the microarray. Detection was carried out with a horseradish peroxidase catalysed chemiluminescence
reaction. All assay steps were conducted with an automated flow-through chemiluminescence microarray readout system. Living
E. coli cells could be detected in 67 min with a detection limit of 4 × 105 cells mL−1. By introduction of the stopped-flow technique and optimisation of interaction time and interaction steps the achieved detection
of E. coli was faster and two orders of magnitude more sensitive than with a conventional ELISA technique in microplates. 相似文献
3.
Increasing the sensitivity in DNA microarray hybridization can significantly enhance the capability of microarray technology
for a wide range of research and clinical diagnostic applications, especially for those with limited sample biomass. To address
this issue, using reverse microemulsion method and surface chemistry, a novel class of homogenous, photostable, highly fluorescent
streptavidin-functionalized silica nanoparticles was developed, in which Alexa Fluor 647 (AF647) molecules were covalently
embedded. The coating of bovine serum albumin on the resultant fluorescent particles can greatly eliminate nonspecific background
signal interference. The thus-synthesized fluorescent nanoparticles can specifically recognize biotin-labeled target DNA hybridized
to the microarray via streptavidin–biotin interaction. The response of this DNA microarray technology exhibited a linear range
within 0.2 to 10 pM complementary DNA and limit of detection of 0.1 pM, enhancing microarray hybridization sensitivity over
tenfold. This promising technology may be potentially applied to other binding events such as specific interactions between
proteins. 相似文献
4.
A screen-printed (SP) microarray is presented as a platform for the achievement of multiparametric biochips. The SP platform
is composed of eight (0.28-mm2) working electrodes modified with electroaddressed protein A-aryl diazonium adducts. The electrode surfaces are then used
as an affinity immobilisation support for the orientated binding of capture monoclonal antibodies, having specificity against
four different point-of-care related proteins (myoglobin, cardiac troponin I, C-reactive protein and brain natriuretic peptide).
The immobilised capture antibodies are involved in sandwich assays of the four proteins together with biotinylated detection
antibodies and peroxidase-labelled streptavidin in order to permit a chemiluminescent imaging of the SP platform and a sensitive
detection of the assayed proteins. The performances of the system in pure buffered solutions, using a 25-min assay duration,
were characterised by dynamic ranges of 0.5–50, 0.1–120, 0.2–20 and 0.67–67 μg/L for C-reactive protein, myoglobin, cardiac
troponin I and brain natriuretic peptide, respectively. The four different assays were also validated in spiked 40-times-diluted
human sera, using LowCross buffer, and were shown to work simultaneously in this complex medium.
Figure Principle of the screen-printed POC microarray and a schematic representation of the assay architecture.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
5.
A protein array chip for label-free optical detection of low molecular weight compounds has been developed. As a proof of
principle, the chip is proven capable of rapidly (approximately 1 min) determining hits from aqueous cocktails composed of
four common narcotics, cocaine, ecstasy, heroin, and amphetamine, using imaging surface plasmon resonance (SPR) as the detection
principle. The chip is produced by injecting a mixture of antibodies and letting them self-sort and bind to narcotic analog
coupled proteins already present in a predefined pattern on the supporting substrate. An indirect detection method, where
antibodies are displaced from the surface upon recognition of their corresponding narcotics, is used to obtain the optical
contrast and thus a detectable SPR and/or ellipsometric signal. Two types of readouts are possible from the present setup:
intensity SPR images and SPR/ellipsometric sensorgrams. Positive hits were routinely obtained for analyte concentrations of
50 pg/μL and the limit of detection, without any parameter optimizations, seems to fall in the range 0.5 pg/μL (1.4 nM) for
heroin, 2.5 pg/μL (8.2 nM) for cocaine, and 5 pg/μL for the other two narcotics (26 nM for ecstasy and 37 nM for amphetamine).
With improved readout possibilities (sampling frequency), signal evaluation algorithms, and antibody–antigen design strategies,
we believe this limit can be further improved. The chip is shown to work for many measurement cycles with excellent reproducibility.
Moreover, with a more advanced fluidic system, excess injected antibodies could be collected and reused for many cycles, which
could make the running costs of the system very low. The chip is in no way limited to detection of narcotics. Other low molecular
weight compounds could easily be detected on the same chip. For example, trinitrotoluene detection has already been demonstrated
using our chip. Possible areas of application for the system are therefore envisaged in airport and underground transport
security, customs, drug interdiction, forensics, and as warning alerts on military equipment and personnel.
Figure Narcotics chip (left) composed of spots of piezodispensed analog-coupled proteins that are loaded with antibodies to form
a patterned regions represented by the capital letter of the four different narcotics in focus. (Right) The same chip showing
hits for ectasy and herion in the cocktail. Both images are obtained in imaging surface plasmon resonance mode 相似文献
6.
Xaver Y. Z. Karsunke Reinhard Niessner Michael Seidel 《Analytical and bioanalytical chemistry》2009,395(6):1623-1630
Pathogen detection is important for health and safety reasons. Several outbreaks all over the world have shown the need for
rapid, qualitative, quantitative, and, particularly, multianalyte detection systems. Hence, a multichannel flow-through chemiluminescence
microarray chip for parallel detection of pathogenic bacteria was developed. The disposable chip made of acrylonitrile–butadiene–styrene
(ABS) copolymer was devised as a support for a multiplexed sandwich immunoassay. Calibration and measurement was possible
in one experiment, because the developed chip contains six parallel flow-through microchannels. Polyclonal antibodies against
the pathogenic bacteria Escherichia coli O157:H7, Salmonella typhimurium, and Legionella pneumophila were immobilized on the chip by microcontact printing in order to use them as specific receptors. Detection of the captured
bacteria was carried out by use of specific detection antibodies labelled with biotin and horseradish peroxidase (HRP)–streptavidine
conjugates. The enzyme HRP generates chemiluminescence after adding luminol and hydrogen peroxide. This signal was observed
by use of a sensitive CCD camera. The limits of detection are 1.8 × 104 cells mL−1 for E. coli O157:H7, 7.9 × 104 cells mL−1 for L. pneumophila, and 2.0 × 107 cells mL−1 for S. typhimurium. The overall assay time for measurement and calibration is 18 min, enabling very fast analysis.
相似文献
7.
Chen XW Xu ZR Qu BY Wu YF Zhou J Zhang HD Fang J Wang JH 《Analytical and bioanalytical chemistry》2007,388(1):157-163
Bead injection in a lab-on-valve (LOV) system was adopted for DNA purification via micro solid-phase extraction (SPE) with
a renewable silica microcolumn packed in a channel of the LOV unit. The complex matrix components in human whole blood, including
proteins, were well eliminated by choosing properly the sample loading and elution media. The DNA purification process was
monitored on-line by using laser-induced fluorescence in a demountable side part of the LOV unit incorporating optical fibers.
The practical applicability of the entire system was demonstrated by separation/purification of λ-DNA in a simulated matrix
and human blood genetic DNA by performing SPE, in situ monitoring of the purified products, and postcolumn PCR amplification.
When DNAs in a simulated matrix (10.0 ng μl−1 λ-DNA, 50 ng μl−1 bovine serum albumin, 1.0% Triton X-100) were processed in the present system and laser-induced fluorescence was monitored
at 610 nm, an overall extraction/collection efficiency of 70% was achieved by employing identical sample loading and an elution
flow rate of 0.5 μl s−1, along with a precision of 3.8% relative standard deviation. DNA separation and purification from human whole-blood samples
were performed under similar conditions.
Figure Lab-on-valve mesofluidic system employed for DNA separation and purification integrating a demountable fluorescence flow cell
for in-situ laser induced fluorescence detection 相似文献
8.
Maria Mallén María Díaz-González Diana Bonilla Juan P. Salvador María P. Marco Antoni Baldi César Fernández-Sánchez 《Analytica chimica acta》2014
Low-density protein microarrays are emerging tools in diagnostics whose deployment could be primarily limited by the cost of fluorescence detection schemes. This paper describes an electrical readout system of microarrays comprising an array of gold interdigitated microelectrodes and an array of polydimethylsiloxane microwells, which enabled multiplexed detection of up to thirty six biological events on the same substrate. Similarly to fluorescent readout counterparts, the microarray can be developed on disposable glass slide substrates. However, unlike them, the presented approach is compact and requires a simple and inexpensive instrumentation. The system makes use of urease labeled affinity reagents for developing the microarrays and is based on detection of conductivity changes taking place when ionic species are generated in solution due to the catalytic hydrolysis of urea. The use of a polydimethylsiloxane microwell array facilitates the positioning of the measurement solution on every spot of the microarray. Also, it ensures the liquid tightness and isolation from the surrounding ones during the microarray readout process, thereby avoiding evaporation and chemical cross-talk effects that were shown to affect the sensitivity and reliability of the system. The performance of the system is demonstrated by carrying out the readout of a microarray for boldenone anabolic androgenic steroid hormone. Analytical results are comparable to those obtained by fluorescent scanner detection approaches. The estimated detection limit is 4.0 ng mL−1, this being below the threshold value set by the World Anti-Doping Agency and the European Community. 相似文献
9.
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
10.
Amatatongchai M Hofmann O Nacapricha D Chailapakul O deMello AJ 《Analytical and bioanalytical chemistry》2007,387(1):277-285
A microfluidic system incorporating chemiluminescence detection is reported as a new tool for measuring antioxidant capacity.
The detection is based on a peroxyoxalate chemiluminescence (PO-CL) assay with 9,10-bis-(phenylethynyl)anthracene (BPEA) as
the fluorescent probe and hydrogen peroxide as the oxidant. Antioxidant plugs injected into the hydrogen peroxide stream result
in inhibition of the CL emission which can be quantified and correlated with antioxidant capacity. The PO-CL assay is performed
in 800-μm-wide and 800-μm-deep microchannels on a poly(dimethylsiloxane) (PDMS) microchip. Controlled injection of the antioxidant
plugs is performed through an injection valve. Of the plant-food based antioxidants tested, β-carotene was found to be the
most efficient hydrogen peroxide scavenger (SA
HP of 3.27 × 10−3 μmol−1 L), followed by α-tocopherol (SA
HP of 2.36 × 10−3 μmol−1 L) and quercetin (SA
HP of 0.31 × 10−3 μmol−1 L). Although the method is inherently simple and rapid, excellent analytical performance is afforded in terms of sensitivity,
dynamic range, and precision, with RSD values typically below 1.5%. We expect our microfluidic devices to be used for in-the-field
antioxidant capacity screening of plant-sourced food and pharmaceutical supplements.
Figure Assembled PDMS microchip sandwiched between two glass plates with the top plate containing capillary reservoirs 相似文献
11.
Non-contact protein microarray fabrication using a procedure based on liquid bridge formation 总被引:1,自引:1,他引:0
Michael Hartmann Johan Sjödahl Mårten Stjernström Johan Redeby Thomas Joos Johan Roeraade 《Analytical and bioanalytical chemistry》2009,393(2):591-598
Contemporary microarrayers of contact or non-contact format used in protein microarray fabrication still suffer from a number
of problems, e.g. generation of satellite spots, inhomogeneous spots, misplaced or even absent spots, and sample carryover.
In this paper, a new concept of non-contact sample deposition that reduces such problems is introduced. To show the potential
and robustness of this pressure-assisted deposition technique, different sample solutions known to cause severe problems or
to be even impossible to print with conventional microarrayers were accurately printed. The samples included 200 mg mL–1 human serum albumin, highly concentrated sticky cell adhesion proteins, pure high-salt cell-lysis buffer, pure DMSO, and
a suspension of 5-μm polystyrene beads. Additionally, a water-immiscible liquid fluorocarbon, which was shown not to affect
the functionality of the capture molecules, was employed as a lid to reduce evaporation during microarray printing. The fluorocarbon
liquid lid was shown to circumvent hydrolysis of water-sensitive activated surfaces during long-term deposition procedures. 相似文献
12.
Oztekin Algul Asiye Meric Serpil Polat N. Didem Yuksek Mehmet S. Serin 《Central European Journal of Chemistry》2009,7(3):337-342
Comparative studies were performed on a series of 2,4-di and 2,3,4-trisubstituted benzimidazo[1,2-a]pyrimidines, which were
synthesized with conventional and microwave heating methods. In microwave irradiation method, approximately, 95–97.5% of the
reaction time was increased and 1–45% yield increase was obtained. All compounds were able to inhibit the growth of the screened
microorganisms in vitro with MIC values between 3.9–250 μg mL−1. The highest activity was expressed by compound IIId (2,4-diphenyl-benzo[4,5]imidazo[1,2-a] pyrimidine), which has the MIC
value of 3.9 μg mL−1 and 31.2 μg mL-1 for Penicillium natatum ATCC 24791 and E. faecalis ATCC 29212, respectively.
相似文献
13.
Competitive adsorption on adsorptive solid-phase microextraction (SPME) fibres implies careful determination of operating
conditions for reliable quantitative analysis of VOCs in indoor air. With this objective, two analytical approaches, involving
non-equilibrium and equilibrium extraction, were compared. The average detection limit obtained for GC-MS analysis of nine
VOCs by the equilibrium method is 0.2 μg m−3, compared with 1.9 μg m−3 with the non-equilibrium method. The effect of the relative humidity of the air on the calibration plots was studied, and
shown to affect acetone adsorption only. Hence, the concentrations that can be accurately determined are up to 9 μmol m−3. The methods were then applied to indoor air containing different concentrations of VOCs. The non-equilibrium method, involving
short extraction time, can be used for detection of pollution peaks whereas equilibrium extraction is preferable for measurement
of sub-μg m−3 ground concentration levels.
相似文献
14.
An improvement of the peak parking technique is described for the serial determination of cations (Na+, , K+, Mg2+, and Ca2+) and anions (Cl−, , and ) using a single pump, a single eluent and a single detector. The present system used commercially-available unmodified cation
exchange and anion exchange columns, which were attached to each switching valve. When 1.75 mM 5-sulfosalicylic acid was
used as the eluent, serial separation of the above cations and anions was achieved in less than 20 min. The proposed ion chromatographic
method was successfully applied to the serial determination of cations and anions in tap water and river water samples. The
limits of detection at S/N=3 for an injection of 20 μl were 16–68 ppb (μg/l) for cations and 15–28 ppb for anions. 相似文献
15.
Determination of norfloxacin in human urine by capillary electrophoresis with electrochemiluminescence detection 总被引:3,自引:0,他引:3
A fast and sensitive approach that can be used to detect norfloxacin in human urine using capillary electrophoresis with end-column
electrochemiluminescence (ECL) detection of is described. The separation column was a 75-μm i.d. capillary. The running buffer was 15 mmol L−1 sodium phosphate (pH 8.2). The solution in the detection cell was 50 mmol L−1 sodium phosphate (pH 8.0) and 5 mmol L−1
The ECL intensity varied linearly with norfloxacin concentration from 0.05 to 10 μmol L−1. The detection limit (S/N=3) was 0.0048 μmol L−1, and the relative standard deviations of the ECL intensity and the migration time for eleven consecutive injections of 1.0 μmol L−1 norfloxacin (n=11) were 2.6% and 0.8%, respectively. The method was successfully applied to the determination of norfloxacin spiked in human
urine without sample pretreatment. The recoveries were 92.7–97.9%.
相似文献
16.
Mohammad Amjadi Jamshid L. Manzoori Javad Hassanzadeh 《Central European Journal of Chemistry》2010,8(3):536-542
The surfactant to dye binding degree (SBDB) methodology was used to determine fluvoxamine maleate and citalopram hydrobromide.
Neutral red and sodium dodecyl sulfate (SDS) were used as the dye and surfactant, respectively, to form dye-surfactant aggregates.
When a cationic drug is added to dye-surfactant mixture, it interacts with the surfactant and decreases the dye-surfactant
binding degree. This decrease is proportional to the drug concentration. This was measured by monitoring the absorbance changes
of the dye at 532 nm. Under the optimum conditions, the calibration graphs were linear over the range of 1.2–15 μg mL−1 and 1.1–15 μg mL−1 for fluvoxamine maleate and citalopram hydrobromide, respectively. The detection limits (signal to noise ratio = 3) were
found to be 0.37 and 0.35 μg mL−1, for fluvoxamine maleate and citalopram hydrobromide, respectively.
相似文献
17.
Du D Huang X Cai J Zhang A Ding J Chen S 《Analytical and bioanalytical chemistry》2007,387(3):1059-1065
A simple method has been devised for immobilization of acetylcholinesterase (AChE)—covalent bonding to a multiwall carbon
nanotube (MWNT)–cross-linked chitosan composite (CMC)—and a sensitive amperometric sensor for rapid detection of acetylthiocholine
(ATCl) has been based on this. Fourier-transform infrared spectroscopy proved that the native structure of the immobilized
enzyme was preserved on this chemically clean and homogeneous composite film, because of the excellent biocompatibility and
non-toxicity of chitosan. Glutaraldehyde was used as cross-linker to covalently bond the AChE, and efficiently prevented leakage
of the enzyme from the film. Because of the inherent conductive properties of the MWNT, the immobilized AChE had greater affinity
for ATCl and excellent catalytic effect in the hydrolysis of ATCl, with a value of 132 μmol L−1, forming thiocholine, which was then oxidized to produce a detectable and rapid response. Under optimum conditions the amperometric
current increased linearly with the increasing concentration of ATCl in the range 2.0–400 μmol L−1, with a detection limit of 0.10 μmol L−1. Fabrication reproducibility of the sensor was good and the stability was acceptable. The sensor is a promising new tool
for characterization of enzyme inhibitors and for pesticide analysis.
Abstract 相似文献
18.
Hong-Juan Qi Su-Hong Chen Min-Li Zhang Hua Shi Sheng-Qi Wang 《Analytical and bioanalytical chemistry》2010,398(6):2745-2750
The utility of DNA microarrays is severely limited by their restricted sensitivity. Tyramine signal amplification (TSA) coupled
with gold label silver stain (GLSS) was introduced in DNA microarrays for visual detection of human pathogenic microorganisms.
First, a TSA system was introduced to the microarrays after the microarrays were prepared and hybridized with biotinylated
targets. This procedure leads to large amounts of biotin-conjugated tyramine depositing at the site of enzyme reaction under
HRP catalysis. Second, streptavidin–nanogold was introduced and accumulated by specific binding of biotin and streptavidin.
Finally, silver staining was performed. The images of the spots were scanned with a visible light scanner and quantified with
ArrayVision 7.0 software. Detection conditions were systematically optimized. Then the sensitivity among TSA coupled with
GLSS, GLSS, and TSA coupled with Cy3 was compared. The optimized conditions were: streptavidin–HRP (1 mg mL−1) dilution 1:1500, biotin–tyramine dilution 1:200 (+0.5% H2O2), streptavidin–nanogold dilution 1:100 (all diluted in 1 × PBS + 1% BSA) and silver stain time of 10 min. The sensitivity
of TSA coupled with GLSS was 100-fold higher than that of GLSS, and was identical with that of TSA coupled with Cy3. Meanwhile,
the specificity of the microarrays were not affected. This implied that TSA coupled with GLSS was a sensitive visual detection
method and would be an ideal alternative to fluorescence-based detection for DNA microarrays. 相似文献
19.
Dispersive liquid-liquid microextraction and liquid chromatographic determination of pentachlorophenol in water 总被引:1,自引:0,他引:1
Khalil Farhadi Mir A. Farajzadeh Amir A. Matin Paria Hashemi 《Central European Journal of Chemistry》2009,7(3):369-374
A simple and sensitive dispersive liquid-liquid microextraction method for extraction and preconcentration of pentachlorophenol
(PCP) in water samples is presented. After adjusting the sample pH to 3, extraction was performed in the presence of 1% W/V
sodium chloride by injecting 1 mL acetone as disperser solvent containing 15 μL tetrachloroethylene as extraction solvent.
The proposed DLLME method was followed by HPLC-DAD for determination of PCP. It has good linearity (0.994) with wide linear
dynamic range (0.1–1000 μg L−1) and low detection limit (0.03 μg L−1), which makes it suitable for determination of PCP in water samples.
相似文献
20.
In-torch LA–ICP–MS was implemented into an in-house-built ICP–TOFMS system. The fast data acquisition capabilities of the
new configuration allowed simultaneous multi-element measurement and readout of in-torch LA–ICP–MS signals with 30 μs time
resolution. The measurements confirmed previously observed fine structures of in-torch generated signals and provided new
insights in the dynamic processes in the plasma on a microsecond time scale. The new setup is described in detail and first
figures of merit are given.
Figure Time dependent multi element signal after laser ablation in the torch of an ICP-TOFMS instrument 相似文献