Enhanced detection sensitivity of pegylated CdSe/ZnS quantum dots-based prostate cancer biomarkers by surface plasmon-coupled emission.

We demonstrate the fabrication and detection of quantum dots (QDs)-based prostate specific antigens (PSAs) cancer protein biochips by using enhanced surface plasmon-coupled emission measurements (SPCE). The PSAs are immobilized on a SiO(2)-protected thin gold substrate and pegylated QDs which conjugated with antibodies of PSA are used as fluorescent probes. Due to the excellent brightness of the QDs and the high directionality of emission, as well as the high light collection efficiency of SPCE, the limit of detection (LOD) is down to 10 fg/mL (equal to 0.3 fM) for the PSA chips by using QDs-based cancer protein. We expect that this QDs-based SPCE measurement system with the low LOD supplies a great potential for detecting various cancer biomarkers that are present in only low concentrations within the human body.