动态自组装载体使二磁粒子能够通过弱磁铁引导
Olga Chovnik1, Renata Balgley, Joel R Goldman
1Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
Journal of the American Chemical Society
|November 28, 2012
概括
研究人员使用可切换光的超偏磁纳米粒子远程引导二磁粒子. 这些纳米粒子可逆地与二磁粒子结合,使得有针对性的输送和释放能够通过光和热进行.
科学领域:
- 材料科学 材料科学 材料科学
- 纳米技术纳米技术
- 磁力学 磁力学 是一种
背景情况:
- 二磁性材料通常被磁场驱逐.
- 微/纳米颗粒的远程操纵对于有针对性的交付和组装至关重要.
- 在纳米级控制粒子相互作用需要先进的响应性材料.
研究的目的:
- 开发一种远程操纵二磁粒子的方法.
- 为了利用双响应纳米粒子用于受控的粒子组装和拆卸.
- 用光和磁场来证明有针对性的输送和释放二磁粒子.
主要方法:
- 具有可光切换和超偏磁性质的双响应纳米粒子的合成.
- 证明可逆纳米粒子吸附在紫外线激发的二磁粒子表面.
- 使用热或环境光进行纳米粒子脱吸.
- 通过纳米粒子膜的动态自我组装诱导有吸引力的相互作用.
- 磁导和功能化二磁粒子的远程传送.
主要成果:
- 通过使用外部磁铁成功实现了对二磁性粒子的远程操纵.
- 使用紫外线和可见光分别证明了可逆纳米粒子吸附/脱附.
- 展示了纳米粒子层拆卸的热和环境光可逆性.
- 具有双响应的纳米粒子的催化量足以用于粒子引导.
- 实现了有针对性的输送和对二磁粒子的控制释放.
结论:
- 双响应纳米粒子能够有效地对二磁粒子进行远程磁性操纵.
- 以光触发的可逆组装/拆卸提供了对粒子相互作用和定位的精确控制.
- 这种技术为各种领域的有针对性的交付和受控释放应用提供了一个新的平台.
相关概念视频
Diamagnetism
Materials consisting of paired electrons have zero net magnetic moments. However, when these materials are placed under an external magnetic field, the moments opposite to the field are induced. Such materials are called diamagnets. Diamagnetism is the response of the diamagnets when placed in an external magnetic field.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
Diamagnetic Shielding of Nuclei: Local Diamagnetic Current
An applied magnetic field causes the electrons present in the molecule to circulate, setting up a local diamagnetic current within the molecule. The local diamagnetic current arising from circulating sigma-bonding electrons induces a magnetic field, Blocal that opposes the applied magnetic field, B0. The effective magnetic field experienced by these nuclei is given by the difference between the applied and local magnetic fields in a phenomenon called local diamagnetic shielding. Essentially,...
Magnetic Damping
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a strong magnet, significant drag acts on the bob as it enters and leaves the field, quickly damping the motion.
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
Ferromagnetism
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
Other Unique Bacteria
Magnetic bacteria exhibit a directed movement called magnetotaxis, driven by structures called magnetosomes. These magnetosomes consist of chains of magnetic particles made of either magnetite (Fe₃O₄) or greigite (Fe₃S₄) and are organized in a linear conformation by a protein scaffold within invaginations of the cell membrane. The bacteria align along the north–south magnetic field lines, much like a compass needle. They are typically microaerophilic or anaerobic and are commonly found near the...
Magnetic Force On A Current-Carrying Conductor
Moving charges experience a force in a magnetic field. Since the magnetic fields produced by moving charges are proportional to the current, a conductor carrying a current creates a magnetic field around it.
Consider a compass placed near a current-carrying wire. The wire experiences a force that aligns the needle of the compass tangentially around the wire. Thus, the current-carrying wire produces concentric circular loops of magnetic field. The magnetic field generated by a wire can be...
Consider a compass placed near a current-carrying wire. The wire experiences a force that aligns the needle of the compass tangentially around the wire. Thus, the current-carrying wire produces concentric circular loops of magnetic field. The magnetic field generated by a wire can be...


