DNA-Functionalized MFe<sub>2</sub>O<sub>4</sub> (M = Fe, Co, or Mn) Nanoparticles and Their Hybridization to DNA-Functionalized Surfaces

Robinson, David B.; Persson, Henrik; Zeng, Hao; Li, Guanxiong; Pourmand, Nader; Sun, Shouheng; Wang, Shan X.

doi:10.1021/la047206o

Cited by 97 publications

(67 citation statements)

References 27 publications

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“…For the past several years, giant magnetoresistance (GMR)-based magnetic biodetection technology, which involves labeling biomolecules with magnetic micro-or nanometer-sized particles and detecting the magnetic fringing fields of the particle labels by GMR sensors after capture by target-probe biomolecular recognition, has received increasing research and development efforts [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. This is because the GMR biosensors are promising for sensitive, large-scale, inexpensive, and portable biomolecular identification.…”

Section: Introductionmentioning

confidence: 99%

Spin valve sensors for ultrasensitive detection of superparamagnetic nanoparticles for biological applications

Sun

Wilson

et al. 2006

Sensors and Actuators A: Physical

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We present giant magnetoresistance (GMR) spin valve sensors designed for detection of superparamagnetic nanoparticles as potential biomolecular labels in magnetic biodetection technology. We discuss the sensor design and experimentally demonstrate that as few as ∼23 monodisperse 16-nm superparamagnetic Fe 3 O 4 nanoparticles can be detected by submicron spin valve sensors at room temperature without resorting to lock-in detection. A patterned self-assembly method of nanoparticles, based on a polymer-mediated process and fine lithography, is developed for the detection. It is found that sensor signal increases linearly with the number of nanoparticles.

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Section: Introductionmentioning

confidence: 99%

Spin valve sensors for ultrasensitive detection of superparamagnetic nanoparticles for biological applications

Sun

Wilson

et al. 2006

Sensors and Actuators A: Physical

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208

106

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“…Magnetic particles are currently used for magnetic separation, to collect tagged cells or DNA sequences, [1][2][3] and for magnetically guided drug delivery. [4][5][6] A key advantage of magnetism lies in the ability to control motion at a distance without perturbing the biological system, as would occur with a large electric field.…”

mentioning

confidence: 99%

Synthesis and Single‐Particle Optical Detection of Low‐Polydispersity Plasmonic‐Superparamagnetic Nanoparticles

et al. 2008

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Both magnetic and plasmonic particles are of increasing interest for biomedical applications. Magnetic particles are currently used for magnetic separation, to collect tagged cells or DNA sequences, [1][2][3] and for magnetically guided drug delivery. [4][5][6] A key advantage of magnetism lies in the ability to control motion at a distance without perturbing the biological system, as would occur with a large electric field. Noble-metal nanostructures are beneficial not only because of their relative ease of biofunctionalization, but also for plasmonic biosensing. [7][8][9][10] Unlike quantum dots, [11] these particles do not show optical bistability or blinking making them competitive with fluorophores for quantifying the number of cell surface markers. [12,13] The main advantages of plasmonic particles are their extremely large molar extinction coefficients and resonant Rayleigh scattering efficiencies, [8] and the exceptional sensitivity of the surface plasmon resonance peak wavelength to changes in the local dielectric environment. Individual plasmonic nanoparticles and nanorods have been detected by using dark field optical microscopy. [13][14][15][16][17] In fact, by using nonmagnetically responsive gold-coated silica particles ($150 nm), Halas and co-workers have demonstrated the capability of gold-shell nanoparticles in detecting low concentrations of analytes in whole blood within minutes without any sample preparation.[18]Here we describe the preparation of iron oxide/gold core/ shell nanoparticles that can be moved magnetically and imaged optically. The synthesis of large-diameter ($150 nm) magnetic plasmonic three-layer composite particles has previously been reported, [19] but our focus here is on smaller particles. The small size of these nanoparticles approaches that of cellmembrane-bound antigens, and is in a range in which particles can be spontaneously internalized by endocytosis. We expect that the combination of magnetic responsiveness, facile bioconjugation, and a localized surface plasmon resonance in these smaller nanoparticles will open new possibilities for in vitro molecular and cell biological applications, including intracellular mechanical and chemical composition analyses, and magnetophoretic cell sorting according to the expression level of cell surface receptors. The magnetic forcẽ F m ¼ ðm pt Á rÞB * that can be applied to a particle depends on the particle magnetic moment m pt . Since m pt ¼ M s V pt , where M s is the saturation magnetization of the material and V pt is the particle volume, a larger size is generally preferable for a strong magnetic response. Thus there is a compromise between large magnetic moments and the desirability of small sizes for new applications.Gold, silver, and SiO 2 core/Au shell particles have been used for plasmonic sensing, where the surface plasmon peak wavelength shifts in response to small changes in the dielectric environment near the particle surface. A core/shell structure with the noble metal in the shell enables the surface plasmon resona...

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“…The silane-coated chips were immersed immediately in a 1 mM solution of mercaptoundecanol in ethanol for at least 16 h. The gold substrates were removed from the thiol solution, washed with ethanol, and dried under an argon stream. The hydroxyl-terminated monolayer was transformed into a thiol-reactive moiety by exposure to a 2.3 mM solution of N-(p-maleimidophenyl) isocyanates (Pierce) in anhydrous toluene at 40°C for 2 h under an argon atmosphere (25,26). Maleimide-modified gold electrodes were washed with anhydrous toluene and dried in a stream of argon.…”

Section: Methodsmentioning

confidence: 99%

Direct electrical detection of DNA synthesis

Pourmand

Karhánek

Persson

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Rapid, sequence-specific DNA detection is essential for applications in medical diagnostics and genetic screening. Electrical biosensors that use immobilized nucleic acids are especially promising in these applications because of their potential for miniaturization and automation. Current DNA detection methods based on sequencing by synthesis rely on optical readouts; however, a direct electrical detection method for this technique is not available. We report here an approach for direct electrical detection of enzymatically catalyzed DNA synthesis by induced surface charge perturbation. We discovered that incorporation of a complementary deoxynucleotide (dNTP) into a self-primed single-stranded DNA attached to the surface of a gold electrode evokes an electrode surface charge perturbation. This event can be detected as a transient current by a voltage-clamp amplifier. Based on current understanding of polarizable interfaces, we propose that the electrode detects proton removal from the 3 -hydroxyl group of the DNA molecule during phosphodiester bond formation.biosensors ͉ charge perturbation detection ͉ polymerization T he label-free, electronic detection of DNA synthesis, without the use of specialized reagents, would greatly simplify the sequencing-by-synthesis technique and accelerate its implementation for rapid DNA sequencing and diagnostics. In this article, we describe the label-free electrical detection method, charge perturbation detection (CPD), applied to sequencing by synthesis, and we discuss its underlying principles. Application of this method could be used to detect any enzymatic DNA or RNA synthesis as well as other biochemical reactions based on similar principles.Self-priming, single-stranded DNA molecules were immobilized on the surface of a gold electrode through a thiol-reactive self-assembled monolayer. The electrode was equilibrated with 10 units of the Klenow (exo Ϫ ) fragment (KF) of DNA polymerase. Fig. 1A shows the signal resulting from the addition of a solution containing a single dNTP (1 mM concentration in the final solution volume) complementary to the nucleotide in the template sequence (top black trace). With no measurable delay, the current rises to a peak of Ϸ400 pA within Ϸ50 ms, decreases rapidly to Ϸ50 pA, and then shows a further, slower transient increase to Ϸ150 pA within 300 ms. The current transient is almost completed at 1 s (Ͻ5% of the peak current). The integral of the measured current is 87 pC (pA⅐s), corresponding to nucleotide incorporation to Ϸ6.0 ϫ 10 11 DNA molecules per cm 2 of the electrode. In contrast, if a solution containing a noncomplementary dNTP was added, no current transient was observed (Fig. 1 A, blue trace). No signal was produced when the complementary dNTP was added in the absence of DNA polymerase (green trace), in the absence of DNA (magenta trace), or if DNA was not immobilized on the electrode surface (orange trace). The lack of a detectable signal in the control experiments demonstrates the clear dependence of the current transient on the...

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DNA-Functionalized MFe₂O₄ (M = Fe, Co, or Mn) Nanoparticles and Their Hybridization to DNA-Functionalized Surfaces

Cited by 97 publications

References 27 publications

Spin valve sensors for ultrasensitive detection of superparamagnetic nanoparticles for biological applications

Spin valve sensors for ultrasensitive detection of superparamagnetic nanoparticles for biological applications

Synthesis and Single‐Particle Optical Detection of Low‐Polydispersity Plasmonic‐Superparamagnetic Nanoparticles

Direct electrical detection of DNA synthesis

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DNA-Functionalized MFe2O4 (M = Fe, Co, or Mn) Nanoparticles and Their Hybridization to DNA-Functionalized Surfaces

Cited by 97 publications

References 27 publications

Spin valve sensors for ultrasensitive detection of superparamagnetic nanoparticles for biological applications

Spin valve sensors for ultrasensitive detection of superparamagnetic nanoparticles for biological applications

Synthesis and Single‐Particle Optical Detection of Low‐Polydispersity Plasmonic‐Superparamagnetic Nanoparticles

Direct electrical detection of DNA synthesis

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DNA-Functionalized MFe₂O₄ (M = Fe, Co, or Mn) Nanoparticles and Their Hybridization to DNA-Functionalized Surfaces