[Retracted] Magnetic Resonance Neuroimaging Contrast Agents of Nanomaterials

Table 2

Organic macromolecules and their advantages of functionalized iron oxide NPs.

Types of polymers	Polymers	Characteristics
Natural polymers	Dextran	Enables optimum polar interactions with iron oxide surfaces, improves the blood circulation time, stability, and biocompatibility
	Chitosan	Nontoxic, alkaline, hydrophilic, widely used as nonviral gene delivery system, biocompatible, and hydrophilic
	Starch	Improves the biocompatibility, good for MRI and drug target delivery
	Gelatin	Used as a gelling agent, hydrophilic emulsifier, biocompatible
Synthetic polymers	Polyethylene glycol (PEG)	Enhances the hydrophilicity and water solubility, improves the biocompatibility, blood circulation times
	Polyvinyl alcohol (PVA)	Prevents agglomeration, giving rise to monodispersibility
	Polymethyl methacrylate (PMMA)	Generally used as thermosensitive drug delivery and cell separation
	Polyacrylic acid (PAA)	Improves stability and biocompatibility as well as bioconjugation