Using fluorescent sensors for highly sensitive and selective detection of biomolecules is a very important strategy in clinical diagnoses as well as biomedical applications. But fluorescent sensors usually suffer from high background signal, which greatly hinders their detection sensitivity. In this work, a novel background-eliminated fluorescence assay for sensitive and selective detection of biomolecule has been developed by coupling feroxyhyte nanosheets (δ-FeOOH) with amino-functionalized silicon quantum dot (Si QDs). We select hyaluronidase (HAase) as the modal target to verify the concept. Si QDs/HA-δ-FeOOH nanoassembly was fabricated by self-assembly of positive Si QDs together with negative HA-δ-FeOOH through electrostatic adsorption. By the introduction of hyaluronidase, the nanoassembly exhibits obviously fluorescence signal recovered. Research suggests that under optimized conditions, this strategy exhibits a good linear response to the concentration of HAase in the range of 0.1 to 12 ng/mL. The detection limit for HAase was 0.02 ng/mL (based on 3σ/S), which was three-order lower than most of the reported fluorescence biosensors for the detection of HAase. Furthermore, this new biosensor has already been applied in the study of urine samples, and the detection results were consistent with those obtained by the clinical tests.
Keywords: Eliminated background signal; High sensitivity; Hyaluronidase; Si QDs/HA-δ-FeOOH nanoprobes.
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