One-step facile synthesis of hyaluronic acid functionalized fluorescent gold nanoprobes sensitive to hyaluronidase in urine specimen from bladder cancer patients

Gold nanoparticles (AuNPs) have been widely used to develop fluorescence resonance energy transfer (FRET) sensors to detect biological substances, environmental pollutants, and disease markers due to their superior quenching capacity to fluorescence signals. In this study, we report the one-step facile synthesis of fluorescein isothiocyanate-labeled hyaluronic acid (FITC–HA) functionalized fluorescent AuNPs based FRET nanoprobes (FITC–HA–AuNPs) via chemical reduction of HAuCl4 by using FITC–HA as both a reducing and stabilizing agent. Then the FITC–HA–AuNPs FRET nanoprobes were used to detect hyaluronidase (HAase), a new type of disease marker, based on the specific enzymatic degradation of HAase to HA. Compared with similar work, the FITC–HA–AuNPs nanoprobes were much easier to prepare and the detection sensitivity was also high for HAase to reach a detection limit of 0.63 U mL−1. More importantly, they also allowed for rapid HAase detection (within 3 h) even in complex biological specimens (urine specimens from patients with bladder cancer) with satisfactory accuracy (recovery efficiency in the range of 92.8–106.9% with RSD≤4.85%). Our studies suggested that such a novel design of FITC–HA–AuNPs FRET nanoprobes developed for sensitive, rapid and accurate detection of HAase had exciting potentials for clinical diagnosis of HAase-related diseases, such as bladder cancer.