Double-Codified Gold Nanolabels for Enhanced Immunoanalysis

Ambrosi, Adriano; Castañeda, María Teresa Uriarte; Killard, Anthony J.; Smyth, Malcolm R.; Alegret, Salvador; Merkoçi, Arben

doi:10.1021/ac070357m

Cited by 347 publications

(240 citation statements)

References 28 publications

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“…[21] The MBs were surface functionalized with AuNPs through Au-S bonds. [22] Briefly, 100 μL SH-MBs solution was added into 1200 μL of TCEP solution with vigorous stirring, which is to make sure all thiols are in reduced form.…”

Section: Scheme 1 Schematic Representation Of the Enzyme Batch Reactomentioning

confidence: 99%

Preparation of Magnetic Microsphere‐Gold Nanoparticle‐Immobilized Enzyme Batch Reactor and Its Application to Enzyme Inhibitor Screening in Natural Extracts by Capillary Electrophoresis

et al. 2017

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A novel strategy for screening the enzyme inhibitors from the natural products by capillary electrophoresis (CE) with a pre column enzyme batch reactor prepared by magnetic microsphere (MB)-gold nanoparticles (AuNPs) is reported. The enzyme batch reactor was prepared by immobilizing the enzymes on the MB conjugated AuNPs (MB-AuNPs). To demonstrate this strategy, xanthine oxidase (XOD) was employed as a model for the activity of the enzyme, inhibition study, and inhibitor screening. With the developed CE method, the enzyme activity was determined by the quantification of the peak area of the product. Enzyme inhibition can be read out directly from the reduced peak area of product in comparison to a reference electropherogram obtained in the absence of any inhibitor. A statistical parameter Z' factor was recommended for evaluation of the accuracy of a drug screening system. In the present study, it was calculated to be 0.7, implying a good accuracy. The screening of two natural extracts from Cortex Phellodendri and Rhizoma Galangae showed that they were positive for XOD inhibition by the present method. Using this immobilized enzyme technology combined with CE separation not only provides the advantages such as convenience, rapidity and low cost, but also provides a new platform for discovering enzyme-inhibitor drug lead compounds.

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Section: Scheme 1 Schematic Representation Of the Enzyme Batch Reactomentioning

confidence: 99%

Preparation of Magnetic Microsphere‐Gold Nanoparticle‐Immobilized Enzyme Batch Reactor and Its Application to Enzyme Inhibitor Screening in Natural Extracts by Capillary Electrophoresis

et al. 2017

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“…[37][38][39] Further, gold nanoparticles can provide a natural environment for bimolecular immobilization and facilitate electron transfer of biosensors because of their large surface area, interesting electrochemical properties, and good biocompatibility. [40][41][42] Therefore, magnetic composite Fe 3 O 4 /Au nanoparticles have had more and more applications in areas such as immunoassays, protein immobilization, cell purification, and magnetically controlled transport of anticancer drugs. [43][44][45][46] Our present work focuses on enzyme-enriched, magnetic functionalized nanoparticles in signal amplification and separation for ultrasensitive detection of AFP.…”

Section: Introductionmentioning

confidence: 99%

Fe3O4/Au magnetic nanoparticle amplification strategies for ultrasensitive electrochemical immunoassay of alfa-fetoprotein

Gan¹,

Jin²,

Li³

et al. 2011

IJN

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Background The purpose of this study was to devise a novel electrochemical immunosensor for ultrasensitive detection of alfa-fetoprotein based on Fe 3 O 4 /Au nanoparticles as a carrier using a multienzyme amplification strategy. Methods and results Greatly enhanced sensitivity was achieved using bioconjugates containing horseradish peroxidase (HRP) and a secondary antibody (Ab 2 ) linked to Fe 3 O 4 /Au nanoparticles (Fe 3 O 4 /Au-HRP-Ab 2 ) at a high HRP/Ab 2 ratio. After a sandwich immunoreaction, the Fe 3 O 4 /Au-HRP-Ab 2 captured on the electrode surface produced an amplified electrocatalytic response by reduction of enzymatically oxidized hydroquinone in the presence of hydrogen peroxide. The high content of HRP in the Fe 3 O 4 /Au-HRP-Ab 2 could greatly amplify the electrochemical signal. Under optimal conditions, the reduction current increased with increasing alfa-fetoprotein concentration in the sample, and exhibited a dynamic range of 0.005–10 ng/mL with a detection limit of 3 pg/mL. Conclusion The amplified immunoassay developed in this work shows good precision, acceptable stability, and reproducibility, and can be used for detection of alfa-fetoprotein in real samples, so provides a potential alternative tool for detection of protein in the laboratory. Furthermore, this immunosensor could be regenerated by simply using an external magnetic field.

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“…[36] Trisodium citrate (5 mL, 1 %) was added to a boiling solution of HAuCl 4 (200 mL, 0.01 %). The solution changed from pale yellow to deep red within several minutes.…”

Section: Methodsmentioning

confidence: 99%

Visual Scanometric Detection of DNA through Silver Enhancement Regulated by Gold‐Nanoparticle Aggregation with a Molecular Beacon as the Trigger

Dong

Yan

et al. 2011

Chemistry A European J

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A convenient and label-free scanometric approach for DNA assay was designed by integrating a metal-ion-mediated conformational molecular beacon (MB) and silver-signal amplification regulated by gold-nanoparticle (AuNP) aggregation. The strategy was based on displacing the interaction between the target DNA sequence and a competitor Hg(2+) ion with a link DNA sequence. In the absence of the target DNA sequence, a link DNA sequence interacted with the Hg(2+) ions, thus forming an inactive cyclic conformation of the MB. This result led to the poor aggregation of polyadenosine-functionalized AuNPs (A-AuNP). In the presence of a target DNA sequence with a stronger affinity than that of the competitor, hybridization between the link DNA and target DNA sequences turned on the trigger. The polythymidine end of the resulting linear duplex structure could react with A-AuNP, thus leading to a cross-linking aggregation. This aggregation weakened AuNP-catalyzed silver enhancement on a spot substrate. Further, by using scanometric detection, the concentration of the target DNA sequence could be conveniently read out within a linear range from 1.0 to 30 nM. Interestingly, in the same amount of Hg(2+) ions, one-base mismatched DNA showed only 22% of the relative gray-scale intensity for the target DNA sequence at the same concentration, thus indicating good specificity. The designed approach, with the help of the ion-mediated conformational MB, was simple, cost effective, adaptable, and convenient and provided significant potential applications in clinical analysis.

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Double-Codified Gold Nanolabels for Enhanced Immunoanalysis

Cited by 347 publications

References 28 publications

Preparation of Magnetic Microsphere‐Gold Nanoparticle‐Immobilized Enzyme Batch Reactor and Its Application to Enzyme Inhibitor Screening in Natural Extracts by Capillary Electrophoresis

Preparation of Magnetic Microsphere‐Gold Nanoparticle‐Immobilized Enzyme Batch Reactor and Its Application to Enzyme Inhibitor Screening in Natural Extracts by Capillary Electrophoresis

Fe3O4/Au magnetic nanoparticle amplification strategies for ultrasensitive electrochemical immunoassay of alfa-fetoprotein

Visual Scanometric Detection of DNA through Silver Enhancement Regulated by Gold‐Nanoparticle Aggregation with a Molecular Beacon as the Trigger

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