共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
On‐Chip Magnetic Platform for Single‐Particle Manipulation with Integrated Electrical Feedback 下载免费PDF全文
Marco Monticelli Andrea Torti Matteo Cantoni Daniela Petti Edoardo Albisetti Alessandra Manzin Erica Guerriero Roman Sordan Giacomo Gervasoni Marco Carminati Giorgio Ferrari Marco Sampietro Riccardo Bertacco 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(7):921-929
Methods for the manipulation of single magnetic particles have become very interesting, in particular for in vitro biological studies. Most of these studies require an external microscope to provide the operator with feedback for controlling the particle motion, thus preventing the use of magnetic particles in high‐throughput experiments. In this paper, a simple and compact system with integrated electrical feedback is presented, implementing in the very same device both the manipulation and detection of the transit of single particles. The proposed platform is based on zig‐zag shaped magnetic nanostructures, where transverse magnetic domain walls are pinned at the corners and attract magnetic particles in suspension. By applying suitable external magnetic fields, the domain walls move to the nearest corner, thus causing the step by step displacement of the particles along the nanostructure. The very same structure is also employed for detecting the bead transit. Indeed, the presence of the magnetic particle in suspension over the domain wall affects the depinning field required for its displacement. This characteristic field can be monitored through anisotropic magnetoresistance measurements, thus implementing an integrated electrical feedback of the bead transit. In particular, the individual manipulation and detection of single 1‐μm sized beads is demonstrated. 相似文献
3.
4.
George Chatzipirpiridis Carmela de Marco Eva Pellicer Olgaç Ergeneman Jordi Sort Bradley J. Nelson Salvador Pané 《Advanced Engineering Materials》2018,20(9)
5.
Magnetic Susceptibility Study of Sub‐Pico‐emu Sample Using a Micromagnetometer: An Investigation through Bistable Spin‐Crossover Materials 下载免费PDF全文
Souleymane Kamara Quang‐Hung Tran Vincent Davesne Gautier Félix Lionel Salmon Kunwoo Kim CheolGi Kim Azzedine Bousseksou Ferial Terki 《Advanced materials (Deerfield Beach, Fla.)》2017,29(46)
A promising and original method to study the spin‐transition in bistable spin‐crossover (SCO) materials using a magnetoresistive multiring sensor and its self‐generated magnetic field is reported. Qualitative and quantitative studies are carried out combining theoretical and experimental approaches. The results show that only a small part of matter dropped on the sensor surface is probed by the device. At a low bias‐current range, the number of detected nanoparticles depends on the amplitude of the current. However, in agreement with the theoretical model, the stray voltage from the particles is proportional to the current squared. By changing both the bias current and the concentration of particle droplet, the thermal hysteresis of an ultrasmall volume, 1 × 10?4 mm3, of SCO particles is measured. The local probe of the experimental setup allows a highest resolution of 4 × 10?14 emu to be reached, which is never achieved by experimental methods at room temperature. 相似文献
6.
Although strong magnetic fields cannot be conveniently “focused” like light, modern microfabrication techniques enable preparation of microstructures with which the field gradients – and resulting magnetic forces – can be localized to very small dimensions. This ability provides the foundation for magnetic tweezers which in their classical variant can address magnetic targets. More recently, the so‐called negative magnetophoretic tweezers have also been developed which enable trapping and manipulations of completely nonmagnetic particles provided that they are suspended in a high‐magnetic‐susceptibility liquid. These two modes of magnetic tweezing are complimentary techniques tailorable for different types of applications. This Progress Report provides the theoretical basis for both modalities and illustrates their specific uses ranging from the manipulation of colloids in 2D and 3D, to trapping of living cells, control of cell function, experiments with single molecules, and more. 相似文献
7.
8.
Qilong Li Haitao Chen Xueyan Feng Chanchan Yu Feng Feng Yahong Chai Pan Lu Tao Song Xiuyu Wang Li Yao 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(15)
Micro‐/nanomotors are widely used in micro‐/nanoprocessing, cargo transportation, and other microscale tasks because of their ability to move independently. Many biological hybrid motors based on bacteria have been developed. Magnetotactic bacteria (MTB) have been employed as motors in biological systems because of their good biocompatibility and magnetotactic motion in magnetic fields. However, the magnetotaxis of MTB is difficult to control due to the lack of effective methods. Herein, a strategy that enables control over the motion of MTB is presented. By depositing synthetic Fe3O4 magnetic nanoparticles on the surface of MTB, semiartificial magnetotactic bacteria (SAMTB) are produced. The overall magnetic properties of SAMTB, including saturation magnetization, residual magnetization, and blocking temperature, are regulated in a multivariate and multilevel fashion, thus regulating the magnetic sensitivity of SAMTB. This strategy provides a feasible method to manoeuvre MTB for applications in complex fluid environments, such as magnetic drug release systems and real‐time tracking systems. Furthermore, this concept and methodology provide a paradigm for controlling the mobility of micro‐/nanomotors based on natural small organisms. 相似文献
9.
10.
11.
12.
Spin‐Crossover Materials: Magnetic Susceptibility Study of Sub‐Pico‐emu Sample Using a Micromagnetometer: An Investigation through Bistable Spin‐Crossover Materials (Adv. Mater. 46/2017) 下载免费PDF全文
Souleymane Kamara Quang‐Hung Tran Vincent Davesne Gautier Félix Lionel Salmon Kunwoo Kim CheolGi Kim Azzedine Bousseksou Ferial Terki 《Advanced materials (Deerfield Beach, Fla.)》2017,29(46)
13.
Guy Koplovitz Darinka Primc Oren Ben Dor Shira Yochelis Dvir Rotem Danny Porath Yossi Paltiel 《Advanced materials (Deerfield Beach, Fla.)》2017,29(17)
There is an increasing demand for realizing a simple Si based universal memory device working at ambient temperatures. In principle, nonvolatile magnetic memory can operate at low power consumption and high frequencies. However, in order to compete with existing memory technology, size reduction and simplification of the used material systems are essential. In this work, the chiral‐induced spin selectivity effect is used along with 30–50 nm ferromagnetic nanoplatelets in order to realize a simple magnetic memory device. The vertical memory is Si compatible, easy to fabricate, and in principle can be scaled down to a single nanoparticle size. Results show clear dual magnetization behavior with threefold enhancement between the one and zero states. The magnetization of the device is accompanied with large avalanche like noise that is ascribed to the redistribution of current densities due to spin accumulation inducing coupling effects between the different nanoplatelets. 相似文献
14.
Multitheragnostic Multi‐GNRs Crystal‐Seeded Magnetic Nanoseaurchin for Enhanced In Vivo Mesenchymal‐Stem‐Cell Homing,Multimodal Imaging,and Stroke Therapy 下载免费PDF全文
Po‐Jung Chen Yi‐Da Kang Chen‐Huan Lin San‐Yuan Chen Chia‐Hung Hsieh You‐Yin Chen Chun‐Wei Chiang Wei Lee Chung‐Y Hsu Lun‐De Liao Chih‐Tai Fan Meng‐Lin Li Woei‐Cherng Shyu 《Advanced materials (Deerfield Beach, Fla.)》2015,27(41):6488-6495
15.
16.
17.
Julia M. McCoey Robert W. de Gille Babak Nasr Jean‐Philippe Tetienne Liam T. Hall David A. Simpson Lloyd C. L. Hollenberg 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(18)
Magnetic microparticles or “beads” are used in a variety of research applications from cell sorting through to optical force traction microscopy. The magnetic properties of such particles can be tailored for specific applications with the uniformity of individual beads critical to their function. However, the majority of magnetic characterization techniques quantify the magnetic properties from large bead ensembles. Developing new magnetic imaging techniques to evaluate and visualize the magnetic fields from single beads will allow detailed insight into the magnetic uniformity, anisotropy, and alignment of magnetic domains. Here, diamond‐based magnetic microscopy is applied to image and characterize individual magnetic beads with varying magnetic and structural properties: ferromagnetic and superparamagnetic/paramagnetic, shell (coated with magnetic material), and solid (magnetic material dispersed in matrix). The single‐bead magnetic images identify irregularities in the magnetic profiles from individual bead populations. Magnetic simulations account for the varying magnetic profiles and allow to infer the magnetization of individual beads. Additionally, this work shows that the imaging technique can be adapted to achieve illumination‐free tracking of magnetic beads, opening the possibility of tracking cell movements and mechanics in photosensitive contexts. 相似文献
18.
19.
Alberto Ghirri Andrea Candini Marco Evangelisti Gian Carlo Gazzadi Florence Volatron Benoit Fleury Laure Catala Christophe David Talal Mallah Marco Affronte 《Small (Weinheim an der Bergstrasse, Germany)》2008,4(12):2240-2246
Prussian blue CsNiCr nanoparticles are used to decorate selected portions of a Si substrate. For successful grafting to take place, the Si surface needs first to be chemically functionalized. Low‐dose focused ion beam patterning on uniformly functionalized surfaces selects those portions that will not participate in the grafting process. Step‐by‐step control is assured by atomic force and high‐resolution scanning electron microscopy, revealing a submonolayer distribution of the grafted nanoparticles. By novel scanning Hall‐probe microscopy, an in‐depth investigation of the magnetic response of the nanoparticles to varying temperature and applied magnetic field is provided. The magnetic images acquired suggest that low‐temperature canted ferromagnetism is found in the grafted nanoparticles, similar to what is observed in the equivalent bulk material. 相似文献
20.
Benjamin Gollnick Carolina Carrasco Mark S. Dillingham Fernando Moreno‐Herrero 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(11):1273-1284
Motor protein functions like adenosine triphosphate (ATP) hydrolysis or translocation along molecular substrates take place at nanometric scales and consequently depend on the amount of available thermal energy. The associated rates can hence be investigated by actively varying the temperature conditions. In this article, a thermally controlled magnetic tweezers (MT) system for single‐molecule experiments at up to 40 °C is presented. Its compact thermostat module yields a precision of 0.1 °C and can in principle be tailored to any other surface‐coupled microscopy technique, such as tethered particle motion (TPM), nanopore‐based sensing of biomolecules, or super‐resolution fluorescence imaging. The instrument is used to examine the temperature dependence of translocation along double‐stranded (ds)DNA by individual copies of the protein complex AddAB, a helicase‐nuclease motor involved in dsDNA break repair. Despite moderately lower mean velocities measured at sub‐saturating ATP concentrations, almost identical estimates of the enzymatic reaction barrier (around 21–24 kBT) are obtained by comparing results from MT and stopped‐flow bulk assays. Single‐molecule rates approach ensemble values at optimized chemical energy conditions near the motor, which can withstand opposing loads of up to 14 piconewtons (pN). Having proven its reliability, the temperature‐controlled MT described herein will eventually represent a routinely applied method within the toolbox for nano‐biotechnology. 相似文献