Fabrication of composite Fe₃O₄ nanoparticles coupled by thermo-responsive and fluorescent Eu complex on surface

Abstract

Stimuli-responsive luminescent hybrid nanoparticles consisting of a magnetite Fe₃O₄ core and a hydrophilic outer shell were synthesized. The shell was a thermo-responsive Eu(III) complex shell, which was synthesized as follows: first, 3-Methacryloxypropyl-trimethoxysilane (MEMO)-co-poly(N-isopropylacrylamide) (NIPAM) (MEMO-co-PNIPAM) copolymer was prepared by free radical polymerization. Subsequently, the copolymer chelated with Europium(III) ions to form a luminescent polymeric layer. Finally, the polymeric shell was grafted onto the Fe₃O₄ nanoparticles surface through chemical action. The sizes of fabricated nanoparticles with core–shell structure were controlled at about 30-45 nm. The as-synthesized nanocomposite particles had excellent fluorescence performance and thermo-responsive behavior, which possessed high color purity and produced red-emission at 613 nm. The lower critical solution temperature (LCST) of thermo-sensitive magnetic nanoparticles was at around 37–38 °C. Cell viability assays suggested that these nanoparticles showed excellent biocompatibility and fluorescence-intensity in vitro.

Graphical Abstract

Keywords:

• Poly(N-isopropylacrylamide)
• Europium
• Fluorescence
• Magnetic Nanoparticles
• 3-Methacryloxypropyltrimethoxysilane (MEMO)

Acknowledgements

The authors would like to thank all of the reviewers of this article for their comments and suggestions. We are grateful to the financially supported by the Keypoint Research and Invention Program (AWS17J016), the Grant of Jilin Province Science & Technology Committee (20170520149JH, 2018101194JC, 20200201098JC), Jilin province science and technology project of traditional Chinese medicine (2017103), Jilin province education department the science and technology development project (JJKH20170408KJ, JJKH 20191059KJ), the Jilin Province Health and health Commission (2014Q049, 2018J114), Jilin City Science & Technology Innovation and Development Projects (No.20190104139), National college student innovation training program (201913706004). The authors would like to thank all of the reviewers of this article for their comments and suggestions.

Additional information

Funding

We are grateful to the financially supported by the Keypoint Research and Invention Program [AWS17J016], the Grant of Jilin Province Science & Technology Committee [20170520149JH, 2018101194JC, 20200201098JC], Jilin province science and technology project of traditional Chinese medicine [2017103], Jilin province education department the science and technology development project [JJKH20170408KJ, JJKH 20191059KJ], the Jilin Province Health and health Commission [2014Q049, 2018J114], Jilin City Science & Technology Innovation and Development Projects [No.20190104139], National college student innovation training program [201913706004].