Stringing beads with magnets

A team of researchers came up with a way to use magnetic fields to guide the assembly of nano-sized chains of magnetic material, surrounded by a porous shell, showing promise for application in biocatalysis, biosensing and drug targeting.

The researchers from China and Qatar¹ coated iron (IV) oxide particles with silica, followed by a layer of long-chain surfactant (a compound that lowers the surface tension between two liquids) to form a porous outer shell. The silica coating was done in a magnetic field to force the coated particles to assemble in chains, not unlike beads on a string. 

The scientists then used electron microscopy, thermal measurements and X-ray diffraction to verify the formation of their desired product. 

The team went on to show that their magnetic porous nanochains can be used to decrease the side effects of treatments for bone diseases such as osteoporosis and osteoarthritis by specifically targeting osteoclasts, giant bone cells that break down bone tissue and are responsible for bone resorption, a part of the natural regeneration process. When hyperactivated, however, these cells can result in inflammatory bone conditions, and are therefore the target of inhibition of osteoporosis and arthritis therapeutics.

According to the study, the nanochains can be loaded with Zoledronate, an osteoclast inhibitor, and are specifically taken up by cells called Bone Marrow-derived Macrophages (BMMs), but not other cell types, which carry the loaded chains to the osteoclasts where the inhibitor can specifically perform its function. Applying a dynamic magnetic field helped accelerate reactions.‪

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