A hyaluronic acid fluorescent hydrogel based on fluorescence resonance energy transfer for sensitive detection of hyaluronidase.

Due to its important role in tumor development and treatment, hyaluronidase (HAase) has been widely investigated in vitro and in vivo. However, such investigation was limited by the absence of sensitive and in situ detection methods. Herein, a hyaluronic acid (HA) hydrogel based on the fluorescence resonance energy transfer (FRET) effect was constructed for the detection of HAase. FITC and AuNPs were covalently coupled with two HA derivatives respectively to form a fluorescent donor-acceptor pair. In the presence of HAase, the hydrogel established by cross-linking of HA derivatives was hydrolyzed specifically. The FRET effect in the hydrogel disappeared and the fluorescence intensity increased proportionally with the changes in the concentration of the HAase. Experiments proved that the HAase sensing system had a wide response range (0.5-100 U/mL), good anti-interference, and excellent biocompatibility. When the hydrogel was used for 3D culture of lung cancer cells, in situ fluorescent response could be achieved. Graphical abstract.