Metal ion-induced chemiluminescence recovery for highly intensive chemiluminescence bifunctionalized polydopamine nanospheres†
It is very important to find good nanomaterials as substrates for the immobilization of chemiluminescence (CL) reagents and catalysts in order to achieve high efficiency in CL functionalized nanomaterials. In this work, N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and Co2+ bifunctionalized polydopamine (Co2+–ABEI–PDA) nanospheres were prepared via a facile strategy by using functional group-rich PDA as a platform for the effective immobilization of ABEI and Co2+ in a robust way for the first time. The Co2+–ABEI–PDA nanospheres were uniform spherical particles with an average diameter of 248 ± 48 nm. The as-prepared Co2+–ABEI–PDA nanospheres exhibited excellent CL efficiency. The CL intensity of Co2+–ABEI–PDA was nearly 4000 times higher than that of ABEI functionalized polydopamine (ABEI–PDA) nanospheres without catalyst in the system. Besides, the CL intensity of Co2+–ABEI–PDA was 320 times higher than that of the Co2+ and ABEI bifunctionalized CaCO3 microspheres. The highly intensive CL mechanism was studied in detail. The inhibition effect towards the free radical scavenging ability of PDA derived from Co2+ coordinated to catechol groups on PDA was observed, resulting in CL recovery. In addition, an optimized ratio of ABEI and Co2+ and a decreased spatial distance between them were achieved in Co2+–ABEI–PDA, which produced a superior catalytic effect to the ABEI–H2O2 system, leading to the outstanding performance of Co2+–ABEI–PDA. The Co2+–ABEI–PDA nanospheres show great application prospects in cold light sources, biosensing and bioimaging etc.