Size and Composition Control of Magnetic Nanoparticles

Abstract

Magnetite nanoparticles are a type of magnetic nanoparticle (MNP) that are inexpensive to make and can be formed in different shapes and sizes. MNPs can be used in DNA/ RNA purification, drug delivery, and other biomedical applications. The commonly employed solvothermal route to make these MNPs gives the most uniform products with the smallest size distribution, but there is a need to identify easily controlled changes to reaction parameters that can reliably tune the size and composition of the MNPs made by this method. In this work we report simple and reliable methods whereby adjusting the total water content and basic salt concentration affords size and composition control, respectively. We employ synchrotron X-ray absorption measurements to prove our method offers monotonic control over MNP composition from maghemite-rich (γ-Fe 2 O 3 ) to the more magnetic magnetite (Fe 3 O 4 ). This demonstrates a simple, general method to produce particles with high magnetite concentration and the desired size.

Effects of Synthesis Conditions on Magnetic Field Sensitive Colloidal Nanoparticle Properties

“…Increasing the nanoparticle size increases the saturated magnetization and creates a superparamagneticferromagnetic transition, so the solubility of these nanoparticles in solution is not long-lived. While the magnetite nanoparticle clusters are synthesized, the desired behavior of the particle is to maintain its superparamagnetic properties and to increase the magnetization in a controlled manner [14].…”