Recent advances in synthesis and surface modification of superparamagnetic iron oxide nanoparticles with silica

•We present recent advances in synthesis of SPION and various routes of producing silica coated SPION•The synthetic routes of producing SPION can be classified into three: physical, chemical and biological methods.•The chemical method is the most cited method of producing SPION and it sub-classified into liquid and gas phase.•The techniques of producing silica coated SPION is grouped into seeded and non-seeded methods.

Research on synthesis of superparamagnetic iron oxide nanoparticles (SPION) and its surface modification for biomedical applications is of intense interest. Due to superparamagnetic property of SPION, the nanoparticles have large magnetic susceptibility, single magnetic domain and controllable magnetic behaviour. However, owing to easy agglomeration of SPION, surface modification of the magnetic particles with biocompatible materials such as silica nanoparticle has gained much attention in the last decade. In this review, we present recent advances in synthesis of SPION and various routes of producing silica coated SPION.