Effect of dispersants on cytotoxic properties of magnetic nanoparticles: a review

Magnetic nanoparticles (MNPs) are widely investigated to evaluate their efficacy for therapeutic carriers, biosensors, contrast agents, therapeutic agents (hyperthermia generators), antimicrobial agents, etc., in extracellular space. When MNPs are used for biomedical applications, the nanoparticles are usually dispersed in phosphate buffer saline or body fluids. Bare MNPs tends to agglomerate and aggregate due to high specific surface energy and magnetic dipolar interactions. Further non-specific adsorption of proteins and salts on bare MNPs leads to collapse of colloidal properties. In order to mitigate the above problems, bare MNPs are ligated with biocompatible dispersants for colloidal stability. Majority MNPs are ligated with dispersants such as oleic acid, oleylamine, dopamine derivatives, zwitterionic compounds and polyethylene glycol, to obtain surfactant ligand monolayer on MNPs. Sometimes, polymers are also used as capping agent or encapsulation material. Surfactant monolayer can further be functionalized with therapeutics, proteins, immunoreceptor, etc., for a specific application. Hence one need to understand biocompatible properties, especially cytotoxicity, of nanoparticles with different dispersant monolayers. In addition, biocompatibility testing is also important because the presence of extractable chemical compounds and agents from synthesis process may influence biocompatibility. Cytotoxicity is most sensitive of the biocompatibility tests and is useful for evaluating these types of harmful reactions. Effect of dispersants on cytotoxicity of MNPs are not reviewed in the literature. The effect of various dispersant on cytocompatibility of various MNPs are systematically presented here. Among all, polyethylene glycol polymer is a universal dispersant with high colloidal stability and very low cytotoxicity. Short-chain zwitterionic surfactant ligands are next best dispersants.

Automated summary

Magnetic nanoparticles are commonly functionalized with dispersants in biomedical applications to enhance stability and reduce toxicity, with polyethylene glycol polymer being a preferable option due to its high colloidal stability and low cytotoxicity.