Analytical Sciences

Portable Smartphone-based Colorimetric Analyzer with Enhanced Gold Nanoparticles for On-site Tests of Seafood Safety

Longjie ZHONG,*,** Jiadi SUN,* Ying GAN,* Shuqi ZHOU,* Zijian WAN,* Quchao ZOU,*,*** Kaiqi SU,* and Ping WANG*,**

*Key Laboratory for Biomedical Engineering of Ministry of Education, Biosensor National Special Laboratory, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China
**State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai, 200050, China
***Department of Clinical Engineering, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, Zhejiang Province, China

Saxitoxin (STX) is one of the paralytic shellfish poisons (PSP) that endanger people’s health. It is necessary to develop methods for the on-site rapid detection for STX in order to prevent safety accidents. An enzyme-linked immunosorbent assay (ELISA) is timesaving and effective, but it is not suitable for large-scale in-field tests due to the expensiveness of commercial ELISA kits and the bulkiness of a microtiter plate reader (MTPR). In this study, a portable smartphone-based colorimetric analyzer (SBCA) with a cost-effictive enhanced gold nanoparticle-based ELISA (EGNB-ELISA) was proposed for STX detection. In a bicinchoninic acid (BCA) protein assay (R² = 0.9939) and a glucose assay (R² = 0.9937), SBCA was shown to be in good agreement with MTPR. EGNB-ELISA had a 12.5-fold lower detection limit (0.4 ng/mL) and a lower detection range (1 – 50 ng/mL, Y = 0.4037X + 0.3564, R² = 0.9797) than the classical ELISA. The recovery rate ranged over 89.1 – 112.2%. The whole detection system, combining both homemade SBCA and ENGB-ELISA, is expected to satisfy the needs of on-site STX sample tests to guarantee seafood safety.

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