Conjugated polyelectrolytes-initiated chemiluminescence: A biosensing platform for label-free and homogeneous DNA detection

► It was found that conjugated polyelectrolytes (CPEs) would initiate the strong chemiluminescence (CL) emission of luminol–H2O2 in weak basic media.
► The catalytic mechanism of CPEs on luminol–H2O2 CL was discussed in detail.
► It was found that the catalytic activity of PMNT (a kind of cationic CPEs) on the luminol–H2O2 CL system was closely relevant to the conformation of PMNT.
► The CL intensity of luminol–H2O2–PMNT system in the presence of single-stranded DNA was much larger than that in the presence of double-stranded DNA.
► A label-free and homogeneous CL method for DNA hybridization detection was developed.

In this study, it was found that conjugated polyelectrolytes (CPEs) would initiate the strong chemiluminescence (CL) emission of luminol–H2O2 in weak basic media. Using CL spectra, ultraviolet visible light spectra, fluorescence spectra and electron spin resonance (ESR) spectra, the catalytic mechanism of CPEs on luminol–H2O2 CL was discussed in detail. Furthermore, it was found that the catalytic activity of poly [3-(3′-N,N,N-triethylamino-1′-propyloxy)-4-methyl-2,5-thiophene hydro chloride] (PMNT) (a kind of cationic CPEs) on the luminol–H2O2 CL system was closely relevant to the conformation of PMNT. The CL intensity of luminol–H2O2–PMNT system in the presence of single-stranded DNA was much larger than that in the presence of double-stranded DNA. By taking advantage of this phenomenon, a label-free and homogeneous CL detection of DNA hybridization is proposed. The detection limit of target DNA (3σ) was estimated to be as low as 3.7×10−13 M. The present CL method for DNA hybridization detection offers the advantages of being simple, cheap, rapid and sensitive.