Sandwich-type immunosensors and immunoassays exploiting nanostructure labels: A review.
TL;DR: This articles reviews recent advances, exploiting nanoparticle labels, in the sandwich-type immunosensors and immunoassays for detection of multivalent antigens/analytes with more than one eptiope due to the use of two matched antibodies.
About: This article is published in Analytica Chimica Acta.The article was published on 2013-01-03. It has received 381 citations till now.
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TL;DR: This review presents the working principles and reaction mechanism of paper-based diagnostics, including dipstick assays, lateral flow assays (LFAs), and microfluidic paper- based analytical devices (μPADs), as well as the selection of substrates and fabrication methods.
796 citations
Cites methods from "Sandwich-type immunosensors and imm..."
...Since electrochemical detection possesses features such as high sensitivity and selectivity, low cost, and portability, it has been extensively applied in various assays, thus providing an alternative detection scheme for paper-based diagnostics (Dungchai et al., 2009; Pei et al., 2013)....
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TL;DR: In this review, it is shown that in the recent years a significant progress was done in the EC analysis of practically all proteins, based on electroactivity of amino acid (aa) residues in proteins.
Abstract: In this review, we wish to show that in the recent years a
significant progress was done in the EC analysis of practically
all proteins, based on electroactivity of amino acid (aa)
residues in proteins. Also electrochemistry of polysaccharides,
oligosaccharides and glycoproteins greatly advanced in creating
important steps for its larger application in the glycoprotein
research. In recent decades, a great effort was devoted to the
discovery and application of biomarkers for analysis of
different diseases, including cancer. In the following
paragraphs, special attention will be paid (i) to intrinsic
electroactivity of peptides and proteins, including the
sensitivity to changes in protein 3D structures, as well as to
recent advances in EC investigations of DNA-protein
interactions, (ii) to intrinsic electroactivity of glycans and
polysaccharides, advances in EC detection of
lectin-glycoprotein interactions and to introduction of
electroactive labels to polysaccharides and glycans and finally
(iii) to EC detection of protein biomarkers, based
predominantly on application of antibodies in immunoassays,
nucleic acid and peptide aptamers for construction of
aptasensors, and lectin biosensors for detection of
glycoprotein biomarkers.
260 citations
TL;DR: This review presents a general picture of the current trends and developments (2008-2013) related to electrochemiluminescence-based immunosensors, and an immuno-like electrochemILuminescent sensor (based on synthetic receptors-molecularly imprinted polymers) is highlighted.
178 citations
TL;DR: The principle of operation, analytical features, various signal amplification strategies as well as the adaptability of the afore-mentioned types of immunosensors to multiplexed formats, (micro) fluidic platforms and paper-based approaches are critically discussed.
Abstract: This review describes the most popular architectures and transduction strategies that have been proposed for the development of electrochemical immunosensors. Relative published work has been classified into four main categories: i) enzyme-labelled immunosensors, ii) metal nanoparticle- and quantum dot-labelled immunosensors, iii) capacitive and (faradic) impedimetric immunosensors, and iv) magnetoimmunosensors. The principle of operation, analytical features, various signal amplification strategies as well as the adaptability of the afore-mentioned types of immunosensors to multiplexed formats, (micro) fluidic platforms and paper-based approaches are critically discussed. Perspectives in point-of-care analysis and commercialization opportunities are also discussed.
176 citations
TL;DR: Several ways of diagnostics have been formulated, which include enzyme-linked immunosorbent assay, chemiluminescent, fluoro-immunoassays, electrical detections, surface plasmon resonance, and colorimetric protein assay, which elucidates the strategies, methods and detection levels involved in these diagnostics on cardiac superior biomarkers.
169 citations
Cites methods from "Sandwich-type immunosensors and imm..."
...When CL systems are combined with the immunoreactions, they became a method to determine the concentrations of samples according to the intensity of the luminescence that the chemical reaction emit (Pei et al., 2013), called the chemiluminescence immunoassays (CLIA)....
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References
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TL;DR: In this paper, eigenfrequenz der Platte infolge Vergroserung der schwingenden Masse is vermessen, so das eine empirische Eichung bei der Schichtwagung mit Schwingquarzen entfallt.
Abstract: Wird eine Fremdschicht auf eine zu Dickenscherungsschwingungen angeregte Schwingquarzplatte aufgebracht, so andert sich die Eigenfrequenz der Platte infolge Vergroserung der schwingenden Masse. Da die Frequenzanderung eines Schwingquarzes sehr genau vermessen werden kann, ergibt sich daraus eine sehr empfindliche Methode zur Wagung dunner Schichten. Massenbelegung der Fremdschicht und Frequenzanderung sind einander proportional. Die Proportionalitatskonstante last sich aus der Eigenfrequenz des Schwingquarzes berechnen, so das eine empirische Eichung bei der Schichtwagung mit Schwingquarzen entfallt. Die Genauigkeit des Schichtwageverfahrens ist in erster Linie durch die Temperaturabhangigkeit der Quarzeigenfrequenz begrenzt und betragt bei 1° C zugelassener Temperaturschwankung etwa ±4 · 10−9 g · cm−2. Das entspricht einer mittleren Dicke von 0,4 A bei der Dichte ϱ=1 g · cm−3. Das Verfahren wurde auch zur direkten Wagung einer Masse ausgenutzt (Mikrowagung). Dabei lies sich eine Genauigkeit von 10−10g erreichen.
8,035 citations
01 Jan 1959
7,057 citations
TL;DR: This tutorial review focuses on the recent development of various synthetic approaches and possibilities for chemical tuning of upconversion properties, as well as giving an overview of biological applications of these luminescent nanocrystals.
Abstract: Lanthanide ions exhibit unique luminescent properties, including the ability to convert near infrared long-wavelength excitation radiation into shorter visible wavelengths through a process known as photon upconversion. In recent years lanthanide-doped upconversion nanocrystals have been developed as a new class of luminescent optical labels that have become promising alternatives to organic fluorophores and quantum dots for applications in biological assays and medical imaging. These techniques offer low autofluorescence background, large anti-Stokes shifts, sharp emission bandwidths, high resistance to photobleaching, and high penetration depth and temporal resolution. Such techniques also show potential for improving the selectivity and sensitivity of conventional methods. They also pave the way for high throughput screening and miniaturization. This tutorial review focuses on the recent development of various synthetic approaches and possibilities for chemical tuning of upconversion properties, as well as giving an overview of biological applications of these luminescent nanocrystals.
2,594 citations
TL;DR: Using QDs linked to immunoglobulin G and streptavidin to label the breast cancer marker Her2, to stain actin and microtubule fibers in the cytoplasm, and to detect nuclear antigens inside the nucleus indicate that QD-based probes can be very effective in cellular imaging and offer substantial advantages over organic dyes in multiplex target detection.
Abstract: Semiconductor quantum dots (QDs) are among the most promising emerging fluorescent labels for cellular imaging. However, it is unclear whether QDs, which are nanoparticles rather than small molecules, can specifically and effectively label molecular targets at a subcellular level. Here we have used QDs linked to immunoglobulin G (IgG) and streptavidin to label the breast cancer marker Her2 on the surface of fixed and live cancer cells, to stain actin and microtubule fibers in the cytoplasm, and to detect nuclear antigens inside the nucleus. All labeling signals are specific for the intended targets and are brighter and considerably more photostable than comparable organic dyes. Using QDs with different emission spectra conjugated to IgG and streptavidin, we simultaneously detected two cellular targets with one excitation wavelength. The results indicate that QD-based probes can be very effective in cellular imaging and offer substantial advantages over organic dyes in multiplex target detection.
2,509 citations
TL;DR: An ultrasensitive method for detecting protein analytes has been developed and comparable clinically accepted conventional assays for detecting the same target have sensitivity limits of ∼3 picomdar, six orders of magnitude less sensitive than what is observed with this method.
Abstract: An ultrasensitive method for detecting protein analytes has been developed. The system relies on magnetic microparticle probes with antibodies that specifically bind a target of interest [prostate-specific antigen (PSA) in this case] and nanoparticle probes that are encoded with DNA that is unique to the protein target of interest and antibodies that can sandwich the target captured by the microparticle probes. Magnetic separation of the complexed probes and target followed by dehybridization of the oligonucleotides on the nanoparticle probe surface allows the determination of the presence of the target protein by identifying the oligonucleotide sequence released from the nanoparticle probe. Because the nanoparticle probe carries with it a large number of oligonucleotides per protein binding event, there is substantial amplification and PSA can be detected at 30 attomolar concentration. Alternatively, a polymerase chain reaction on the oligonucleotide bar codes can boost the sensitivity to 3 attomolar. Comparable clinically accepted conventional assays for detecting the same target have sensitivity limits of ∼3 picomdar, six orders of magnitude less sensitive than what is observed with this method.
2,430 citations