polish the following sentence：In this work we designed a multicolor visual colorimetric sensor for the determination of HAase activity in human serum The strategy utilized enzyme-responsive smart hydr

In this study, we have crafted a multicolor visual colorimetric sensor that can accurately determine the activity of HAase in human serum. Our approach involved utilizing enzyme-responsive smart hydrogels to recognize HAase, and etching Au NBPs to generate multi-color for read-out. As the HAase activity increased, the LSPR of Au NBPs gradually shifted towards the blue spectrum, accompanied by bright color changes. This visual cue can be easily observed by the naked eye, allowing for a simple yet effective means of detecting HAase activity. Additionally, the shift of LSPR of Au NBPs can provide an accurate quantification of the activity. Our method is not only low-cost and sensitive, but it can also be applied to the point-of-care testing of HAase in various biological and medical applications