Centrifugation assembly proceeded tube-based SERS sensor for field-deployable solution detection

A novel tube-based SERS sensor is proposed to simplify the SERS fabrication and achieve field-deployable detection via a successive process of in-situ synthesis of Ag-NPs solution, centrifugal assembly of Ag-NPs film and separation-free detection of complex matrix, which offers the outstanding advantages of user-friendly operation, easy integration, and mass production. The high-density Ag-NPs are uniformly assembled on the inner surface of centrifuge tube, providing large amounts of SERS hotspots to enlarge the high sensitivity for targeted molecules. The tube-based sensor exhibits ultrahigh sensitivity with an average enhancement factor of 8.7 × 107, and improved reproducibility with a relative signal deviation down to 3.92%. Based on the tube-based sensor, the field-deployable rapid detection of thiram and melamine added in milk can be directly realized without any pretreatment. Therefore, the demonstrated portable and cost-effective tube-based SERS sensors offer promising potentials for field-deployable detection in environmental monitoring and food safety.