HBV is a major global health challenge, with an estimated 300 million chronic carriers worldwide. Chronic HBV infection is a leading cause of liver cirrhosis worldwide and is implicated in a significant percentage of liver cancer cases. - Thus, sensitive detection of HBV is crucial for early diagnosis and protection of people's health and safety. The hepatitis B surface antigen (HBsAg) is an important biomarker and is commonly used as a serologic marker for HBV infection. - Therefore, rapid, sensitive, and reliable detection of HBsAg is critically needed for HBV diagnosis, especially for point-of-care (POC) diagnosis in resource-limited settings.