A dual-signals response electrochemiluminescence immunosensor based on PTC-DEPA/KCC-1 NCs for detection of procalcitonin

Taking advantage of the dual-signals response at both positive and negative cycles in S2O82− solution, perylene-3,4,9,10-tetracarboxylic acid- N,N-Diisopropylethylenediamine/mesoporous fibrous silica nanocomposites (PTC-DEPA/KCC-1 NCs) were chosen as the luminophore signal probe for procalcitonin detection in this paper. In addition, a sandwich-type of electrochemiluminescene (ECL) immunosensor based on PTC-DEPA/KCC-1 NCs was developed for the first time. Because N,N-Diisopropylethylenediamine (DPEA) could provide electron to perylene-3,4,9,10-tetracarboxylic acid (PTCA), PTC-DEPA exhibited much higher luminous intensity compared with the PTCA molecule. Moreover, mesoporous fibrous silica particle (KCC-1) possessed a unique feature to further reduce diffusion limitation due to the dendritic fiber, which could enhance the loading amount and further increase the luminous intensity. Therefore, the functionalized PTC-DEPA/KCC-1 NCs were used to load the detection antibody (Ab2). In addition, Au@Ag core/shell nanoparticles (Au@Ag NPs) with excellent conductivity were synthesized to immobilize antibody (Ab1) with increased amount. Based on sandwiched immunoreactions, this developed strategy combining ECL immunosensor with excellent linearity in concentrations of procalcitonin from 0.05 pg mL−1 to 10 ng mL−1 and a detection limit of 0.017 pg mL−1, provided ample potential for further bioanalysis and clinical study.