An electrochemiluminescence sensing for DNA glycosylase assay with enhanced host-guest recognition technique based on α-cyclodextrin functionalized gold/silica cell-shell nanoparticles

An electrochemiluminescence (ECL) sensing for sensitive assaying of active DNA glycosylase was developed using the enhanced host-guest recognition technique. The α-cyclodextrin was selected as the host molecule which captured the guest-labeled ECL probe to the surface of electrode by the host-guest recognition. The ECL probe can be protected from the digestion of exonuclease I (Exo I) and exonuclease III (Exo III) with the presence of the target enzyme human 8-oxoguanine DNA glycosylase 1 (hOGG 1), resulting in the ECL emission intensity was correlated with the quantity of hOGG 1. The α-cyclodextrin functionalized gold/silica (Au/SiO2) cell-shell nanoparticles was prepared to enhance the host-guest recognition sensitivity. Because of the increased recognition sites provided by α-cyclodextrin functionalized Au/SiO2 cell-shell nanoparticles, the nanoparticle-modified electrode displayed a high capacity for the guest ECL probe, and four fold enhancement of the ECL signals was achieved. The as-prepared ECL sensing exhibits excellent analytical property for the detection of hOGG 1 in the linear range of 2–100 U mL−1 with a detection limit of 0.225 U mL−1 (S/N = 3). Interference tests show that the ECL intensity of the interferents human apurinic/apyrimidinic endonuclease (APE 1), T4 endonuclease V (T4 PDG) and endonuclease III (Endo III) is within 36.5 to 44.7% of that of hOGG 1. The ECL sensing exhibits long-term stability with a relative standard deviation (RSD) of 1.6% for 16 cycles of continuous potential scans, and the life time of the ECL sensing is up to 20 days. The obtained results in this study indicate that the proposed ECL sensing possesses high sensitivity, specificity and stability and provides a powerful tool for assaying hOGG 1 activity.