Magnetic nanostirrs are crucial to achieve rapid mixing of tiny droplets and improve the efficiency of chemical reactions. Its development process mainly went through the following three stages:

1. Magnetotactic bacteria

In 1775, Richard P. Blakemore first proposed the concept of "magnetotactic bacteria". This type of bacteria contains iron-rich particle chains, namely magnetosomes, whose main component is Fe3O4 or/and Fe3S4, so magnetotactic bacteria can Movement occurs under the influence of a magnetic field [1]. Inspired by this magical property, researchers began to use magnetotactic bacteria as magnetic nanostirring elements (MNSR), which were encapsulated in microdroplets and used to stir solutions to accelerate mass transfer and significantly increase the reaction rate [2].

2. Artificial synthesis

Cultivation of magnetotactic bacteria is time-consuming and highly specialized, so researchers began to artificially produce MNSR. MNSR prepared by coating the surface of linear single chains assembled with Fe3O4 particles with silica or polymer is small in size, can remain in a suspended state, generates many vortices during the stirring process, and can achieve effective liquid mixing [3]. Researchers often use magnetic field-induced self-assembly in solution to prepare MNSR, but this method has shortcomings such as small effective induction area, low efficiency, complicated post-processing, and large batch variability. Professor Chen Hongyu's scientific research team creatively used electrospinning technology to quickly prepare Fe3O4 magnetic nanostirrs, achieving a simple, flexible and controllable synthesis of stirrers of different sizes [4].

3. Expand applications

In recent years, MNSR has begun to be used as a catalyst carrier. Yang et al. used the prepared magnetic nanostirr containing palladium nanoparticles (Fe3O4 NC PZS Pd) for the catalytic hydrogenation of methylene blue in a microscopic system, showing better performance than commercial Pd/C Better catalytic activity [5]. Chen Hongyu's research group coated the surface of the prepared magnetic nanostirr NSB-4 with a layer of gold nanowires for the catalytic reduction of 4-nitrophenol, and the color of the yellow solution quickly became lighter (Figure 1) [4][4]

Professor Chen Hongyu of Nanjing University of Technology has focused on the synthesis of magnetic nanostirrs for more than ten years. The Fe3O4 magnetic nanostirr developed has a uniform appearance and stable quality, and can meet the requirements of stirring in small spaces in different scenarios. This product is exclusively sold by J&K Scientific:

Product name:

Magnetic nano-stir bars, silica coated iron oxide (II,III), 0.1 mg/ml in ethanol

References

1. Blakemore R. Magnetotactic bacteria[J][J][J][J][J]. Angewandte Chemie International Edition, 2015, 54(9): 2661-2664.