Recently
we have demonstrated that the surface plasmon of noble
metal nanoparticles can effectively enhance the ECL intensity of Ru(bpy)3
2+, and we named this detection principle as surface-enhanced
electrochemiluminescence (SEECL-I). However, SEECL based on photomultiplier
tube (PMT) detection can only detect one target at a time, which is
not suitable for multiple targets detection. In this work, we combined
our previous developed SEECL with a bioimaging device to develop a
novel multiplexed immunassay for simultaneous and fast analysis of
cancer markers. A core–shell nanocomposite consisted of gold–silicon
dioxide nanoparticles doped with Ru(bpy)3
2+(Au@SiO2-Ru) with strong ECL emission was employed as ECL label due
to the localized surface plasmon resonance (LSPR) of AuNPs, which
can significantly enhance the ECL emission of Ru(bpy)3
2+. The ECL signals from the 4 × 4 electrode arrays were
collected using the constant potential method (current–time
curve method) imaging with a sCOMS camera. As a proof-of-concept application,
we demonstrated the use of the proposed SEECL-I for simultaneous detection
of carcinoembryonic antigen (CEA), neuron specific enolase (NSE),
and squamous cell carcinoma antigen (SCC) in exhaled breath condensates
(EBCs) with low detection limit (LOD) of 0.17, 0.33, and 0.33 pg/mL
(S/N = 3), respectively. The results demonstrated that the proposed
SEECL-I strategy can provide a high sensitivity, fast analysis, and
high-throughput platform for clinical diagnosis of cancer markers
in EBCs.