Metal ion-induced chemiluminescence recovery for highly intensive chemiluminescence bifunctionalized polydopamine nanospheres

Abstract

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.