A novel chemiluminescence imaging immunosensor for prostate specific antigen detection based on a multiple signal amplification strategy.

A novel chemiluminescence (CL) imaging platform was constructed for prostate specific antigen (PSA) detection in a multiple signal amplifying manner. To construct the platform, the primary antibody for PSA was firstly immobilized on a O-ring area of a glass slide for recognizing the PSA. The horseradish peroxidase (HRP) and the secondary antibody of PSA (Ab) functionalized Au NPs (HRP-Au NPs-Ab) were modified on the platform through immunoreaction between PSA and Ab. The excellent catalytic effect of Au NPs and HRP on the HRP-Au NPs-Ab to the luminol-HO CL system provided the dual-signal amplification for PSA detection. To further enhance the sensitivity, tyramine signal amplification (TSA) strategy was introduced: tyramine-HRP conjugates were added into the O-ring reservoir and thus tyramine-HRP repeats formed in the presence of HO, generating a multiple signal amplification because of the large amounts of HRP on the sensing interface. The excellent performance of HRP-Au NPs-Ab and TSA strategy endows the CL platform with high sensitivity. The PSA was detected with a photomultiplier tube (PMT) and visually analyzed by a charge coupled device (CCD), respectively. The linear ranges of PMT and CCD for PSA are 0.1-100.0 ng mL with a detection limit of 0.05 pg mL and 0.5 - 100.0 ng mL with a detection limit of 0.1 pg mL, respectively. The levels of PSA in several human serum samples were determined and the recoveries are ranged from 82.5% - 117.0%. This CL immunosensing platform holds great potential for bioactive molecules detection visually and sensitively.