Chemiluminescent magnetic nanoparticles with good catalytic activity and rapid separation capability and sensitive...

It is of considerable importance to develop chemiluminescent functionalized nanomaterials (CF-NMs) with good catalytic activity, high chemiluminescence (CL) efficiency and good stability, and rapid magnetic separation capability, achieving excellent performance in CL biosensing. In this study, N-(4-aminobutyl)-N-ethylisoluminol (ABEI)-functionalized CuFe₂O₄ magnetic nanomaterial (ABEI/CuFe₂O₄) with high catalytic activity was synthesized by virtue of a solvothermal and post-functionalization method. ABEI/CuFe₂O₄ showed outstanding CL properties, superior to ABEI-CuFe₂O₄ in liquid phase. This reveals that the immobilization of ABEI on the surface of CuFe₂O₄ exhibits unique heterogeneous catalytic property. The catalytic ability of CuFe₂O₄ was better than that of CoFe₂O₄, ZnFe₂O₄, MnFe₂O₄, and NiFe₂O₄. It is suggested that the peroxide-like activity as well as Cu²⁺ and Cu⁰ enriched on the surface of ABEI/CuFe₂O₄ opened up a dual route for synergistic catalysis of H₂O₂. ABEI/CuFe₂O₄ also demonstrated good superparamagnetism and magnetic separation could be carried out in 2 min, which is advantageous for the separation and purification of ABEI/CuFe₂O₄ during the synthetic procedures and bioassays. Owing to the sensitive response of ABEI/CuFe₂O₄ to H₂O₂, an enzyme-free sensor was developed for the detection of H₂O₂ with a wide linear range over 5 orders of magnitude of H₂O₂ concentrations and a low detection limit of 5.6 nM. The as-developed sensor is sensitive, stable, and convenient. This work provides a new family member of nanomaterials with good magnetism and CL activity as well as good stability. The developed ABEI/CuFe₂O₄ shows great prospects in biocatalysis, bioassays, biosensing, and bioimaging, etc.