Highly sensitive metal-enhanced fluorescence platform based on high-quality CdSe/ZnS quantum dots and gold nanodendrites

Fluorescence immunosensors are highly demanded for diagnosing, monitoring and pathogenesis of diseases. Yet, the low sensitivity due to the weak fluorescence intensity of commonly employed fluorescent materials is the major obstacle towards early accurate diagnosis of targeted diseases. Herein, we resolve this issue by designing a highly sensitive fluorescence platform via employing colloidal quantum dots (QDs)-metal nanoparticles hybrid system. The QDs exhibit high chemical, thermal, and optical stability, excellent biocompatibility with ultrahigh quantum yield (∼88 %). They exhibit a core/shell architecture with type-I band alignment. The gold nanodendrites (AuNDs) synthesized via seed growth method with controllable sizes exhibit anisotropic shape, which maximizes the impacts of local surface plasmon resonance to amplify the fluorescence performance of colloidal QDs. Utilizing the designed platform and taking C-reactive protein as a testcase, we achieve ∼17-fold sensitivity improvement compared with metal nanoparticles free sensing platform, and a wide detection range between 0.25 ng/mL and 1000 ng/mL, and a low detection limit of 0.056 ng/mL. The designed sensing platform has been extended for the detection of real blood and tissue samples, and competing results have been delivered compared with the prevailing detecting technique. The present work reports a novel route of designing biological sensing platform through fluorescence amplification, which holds great potential for highly sensitive and throughput detection in clinical applications, and is widely applicable for highly sensitive detection of other biomarkers in biomedical applications.