Gold nanoflowers labelled lateral flow assay integrated with smartphone for highly sensitive detection of clenbuterol in swine urine

ABSTRACT Here, a gold nanoflowers (AuNFs) labelled lateral flow assay integrated with smartphone was developed. In the proposed assay, high sensitivity was achieved without additional excitation light source as AuNFs was used as label under natural light. Moreover, with smartphone, subtle changes of optical signals from the test line was collected and distinguished portably. Thus, portable quantitative detection of clenbuterol (Clen) with high sensitivity was achieved. The limit of detection (LOD) of the proposed assay for Clen was 12.5？pg/mL, which was 4.9 times lower than that of the traditional lateral flow assay based on gold nanospheres (61.4？pg/mL). The linear range was 0.1–5.0？ng/mL. The average recoveries in swine urine were 92.7–112.0%, with coefficients of variation of 1.8–7.4%. The detection results were highly correlated with those of LC-MS/MS. Therefore, the assay is promising for the extend analysis fields with the advantages of sensitive, portable, and accurate