Efficient Collection and Sensitive Detection Using Conducting Magnetic Microbeads

Shiigi, Hiroshi; Kinoshita, Takamasa; Shibutani, Naoki; Nishino, Tomoaki; Nagaoka, Tsutomu

doi:10.1021/ac500452w

Cited by 14 publications

(8 citation statements)

References 39 publications

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“…Normally, this flux is determined by diffusion, and because particles are large in comparison to molecules, their diffusion coefficients, the hence the limits of detection (LODs) of collision experiments, are generally not very low. To achieve lower LODs, diffusion must be supplemented by a second means of mass transfer like electrophoresis,4 pressure-driven flow,24,25 or, as in the present case, a magnetic force 32–37. Note that attempts to use electrophoresis and pressure-driven flow to lower LODs have not been very successful.…”

Section: Resultsmentioning

confidence: 95%

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Direct electrochemical detection of individual collisions between magnetic microbead/silver nanoparticle conjugates and a magnetized ultramicroelectrode

2015

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Section: Resultsmentioning

confidence: 95%

“…The procedure for preparing cMμBs is described in detail in the ESI† but is briefly outlined here 32. We start with commercially available iMμBs surface-functionalized with negatively charged carboxylate groups.…”

Section: Resultsmentioning

confidence: 99%

Direct electrochemical detection of individual collisions between magnetic microbead/silver nanoparticle conjugates and a magnetized ultramicroelectrode

2015

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“…The Au-coated MMBs were prepared with the procedure in the previous report, 42 which were characterized by scanning electron microscope (JSM-7800F; JEOL, Tokyo, Japan) and energy-dispersive spectroscopy (NS7; Thermo Fisher Scientific, Waltham, MA, USA; Figure 1A). Immobilization of the thiolated peptide (DAHSSKLQLAPPC) was performed by mixing 50 mg Au-coated MMBs with 0.5 mL of 1 mM peptide in phosphate buffer for 3 hours.…”

Section: Preparation Of Peptide-functionalized Mmbsmentioning

confidence: 99%

Gold nanoparticle-based colorimetric method for the detection of prostate-specific antigen

Xia¹,

Deng²,

Wang³

et al. 2018

IJN

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BackgroundProstate-specific antigen (PSA), a serine protease, is a biomarker for preoperative diagnosis and screening of prostate cancer and monitoring of its posttreatment.MethodsIn this work, we reported a colorimetric method for clinical detection of PSA using gold nanoparticles (AuNPs) as the reporters. The method is based on ascorbic acid (AA)-induced in situ formation of AuNPs and Cu2+-catalyzed oxidation of AA. Specifically, HAuCl4 can be reduced into AuNPs by AA; Cu2+ ion can catalyze the oxidation of AA by O2 to inhibit the formation of AuNPs. In the presence of the PSA-specific peptide (DAHSSKLQLAPP)-modified gold-coated magnetic microbeads (MMBs; denoted as DAHSSKLQLAPP-MMBs), complexation of Cu2+ by the MMBs through the DAH–Cu2+ interaction depressed the catalyzed oxidation of AA and thus allowed for the formation of red AuNPs. However, once the peptide immobilized on the MMB surface was cleaved by PSA, the DAHSSKLQ segment would be released. The resultant LAPP fragment remaining on the MMB surface could not sequestrate Cu2+ to depress its catalytic activity toward AA oxidation. Consequently, no or less AuNPs were generated.ResultsThe linear range for PSA detection was found to be 0~0.8 ng/mL with a detection limit of 0.02 ng/mL. Because of the separation of cleavage step and measurement step, the interference of matrix components in biological samples was avoided.ConclusionThe high extinction coefficient of AuNPs facilitates the colorimetric analysis of PSA in serum samples. This work is helpful for designing of other protease biosensors by matching specific peptide substrates.

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“…Magnetic beads have drawn great concern because of their convenience, quick magnetic responsiveness, easy automation and good liquid-phase kinetics [79], which have been increasingly used in the miRNA sensing field. Generally, they are utilized as the first step in the detection procedure to achieve additional signal amplification.…”

Section: Additional Micro- and Nano-materialsmentioning

confidence: 99%

Avenues Toward microRNA Detection In Vitro: A Review of Technical Advances and Challenges

Zhu

Tan

et al. 2019

Computational and Structural Biotechnology Journal

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Over the decades, the biological role of microRNAs (miRNAs) in the post-transcriptional regulation of gene expression has been discovered in many cancer types, thus initiating the tremendous expectation of their application as biomarkers in the diagnosis, prognosis, and treatment of cancer. Hence, the development of efficient miRNA detection methods in vitro is in high demand. Extensive efforts have been made based on the intrinsic properties of miRNAs, such as low expression levels, high sequence homology, and short length, to develop novel in vitro miRNA detection methods with high accuracy, low cost, practicality, and multiplexity at point-of-care settings. In this review, we mainly summarized the newly developed in vitro miRNA detection methods classified by three key elements, including biological recognition elements, additional micro-/nano-materials and signal transduction/readout elements, their current challenges and further applications are also discussed.

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Efficient Collection and Sensitive Detection Using Conducting Magnetic Microbeads

Cited by 14 publications

References 39 publications

Direct electrochemical detection of individual collisions between magnetic microbead/silver nanoparticle conjugates and a magnetized ultramicroelectrode

Direct electrochemical detection of individual collisions between magnetic microbead/silver nanoparticle conjugates and a magnetized ultramicroelectrode

Gold nanoparticle-based colorimetric method for the detection of prostate-specific antigen

Avenues Toward microRNA Detection In Vitro: A Review of Technical Advances and Challenges

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