Electrocatalytic activity of Co3O4 quantum dots supported on aminated carbon nanotubes and their application for sensitive electrochemical immunosensing of prostate-specific antigen

We report here the high electrocatalytic activity of Co3O4 quantum dots (QDs) supported on aminated carbon nanotubes (ACNTs) toward H2O2 reduction and their application for sensitive electrochemical immunosensing of prostate-specific antigen (PSA). High density and uniformCo(3)O(4) QDs with sizes less than 5 nm were facilely prepared on ACNTs. Due to the synergetic effect between Co3O4 QDs and ACNTs, the Co3O4 QDs-ACNTs were used as an efficient electrocatalyst for H2O2 reduction. Because of the ultrasmall size of Co3O4 QDs, the electrocatalytic activity of Co3O4 QDs-ACNTs toward H2O2 reduction was much higher than that of Co3O4 nanoparticles (ca. 18 nm) supported on ACNTs. The Co3O4 QDs-ACNTs were exploited as efficient catalytic labels for the construction of a sandwiched-type immunosensor. The immunosensor showed a broad linear range between 100 fg mL(-1) and 100 ng mL(-1) for PSA detection, and the detection limit is as low as 20 fg mL(-1) (S/N = 3). This immunosensor was successfully used for detecting PSA in a serum sample.

我们在此报道了氨基化碳纳米管（ACNTs）负载的四氧化三钴量子点（QDs）对过氧化氢还原的高电催化活性及其在前列腺特异性抗原（PSA）灵敏电化学免疫传感中的应用。在ACNTs上简便地制备了尺寸小于5nm的高密度且均匀的四氧化三钴量子点。由于四氧化三钴量子点和ACNTs之间的协同效应，四氧化三钴量子点 - ACNTs被用作过氧化氢还原的高效电催化剂。由于四氧化三钴量子点的超小尺寸，四氧化三钴量子点 - ACNTs对过氧化氢还原的电催化活性远高于ACNTs负载的四氧化三钴纳米颗粒（约18nm）。四氧化三钴量子点 - ACNTs被用作构建夹心式免疫传感器的高效催化标记物。该免疫传感器在100fg/mL到100ng/mL之间对PSA检测呈现出较宽的线性范围，检测限低至20fg/mL（信噪比 = 3）。这种免疫传感器已成功用于检测血清样本中的PSA。