One-pot synthesis of polyamines improved magnetism and fluorescence Fe3O4–carbon dots hybrid NPs for dual modal imaging

Abstract

A one-step hydrothermal method was developed to fabricate Fe₃O₄–carbon dots (Fe₃O₄–CDs) magnetic–fluorescent hybrid nanoparticles (NPs). Ferric ammonium citrate (FAC) was used as a cheap and nontoxic iron precursor and as the carbon source. Moreover, triethylenetetramine (TETA) was used to improve the adhesive strength of CDs on Fe₃O₄ and the fluorescence intensity of CDs. The prepared water-soluble hybrid NPs not only exhibit excellent superparamagnetic properties (M_s = 56.8 emu g⁻¹), but also demonstrate excitation-independent photoluminescence for down-conversion and up-conversion at 445 nm. Moreover, the prepared water-soluble Fe₃O₄–CDs hybrid NPs have a dual modal imaging ability for both magnetic resonance imaging (MRI) and fluorescence imaging.