Au@Pt nanozyme-based smart hydrogel for visual detection of hyaluronic acid

Hyaluronidase (HAase), is a naturally occurring glycosidase with the ability to break down glycosidic bonds within hyaluronic acid (HA) chains. In this paper, we propose a portable smartphone and Surface-enhanced Raman scattering (SERS) dual-mode sensor based on Au@Pt nanozyme coated with HA hydrogel to realize sensitive detection of HAase. Au@Pt nanozyme has excellent peroxidase-like activity, oxidase-like activity and catalase-like activity under acidic conditions. When HAase is present, the hydrogel structure of HA was hydrolyzed and gradually released Au@Pt nanozyme. The released Au@Pt nanozyme is used to catalyze the hydrogen peroxide system, so that 3,3′,5,5′-tetramethylbenzidine (TMB) can be oxidized into blue 3,3′,5,5′-tetramethylbenzidine (TMB ox ). Therefore, based on the above strategies, a dual-mode sensing platform for HAase detection by smartphone and SERS was established. The linear range of the dual-mode sensor platform are 2–30 U/mL and 2–80 U/mL, and the detection limits are 1.0386 U/mL and 0.004 U/mL, respectively. The dual-mode smartphone and SERS sensor platform, a combination of smartphone and Raman spectrometer, is successfully further applied to biological urine samples. This portable dual-mode sensor based on intelligent hydrogel coated nanozyme not only opens up a new way for instant detection, but also has potential applications in clinical diagnosis.