A novel electrochemical immunosensor for hepatitis B surface antigen based on Fe3O4 nanoflowers and heterogeneous chain reaction signal amplification strategy
Authors: Li, Xiaoyan; Liu, Tianchen; Zhang, Yun; Ni, Xiao; Hossain, M. Nur; Chen, Xiaojun; Huang, He; Kraatz, Heinz-Bernhard
Herein, a novel sandwich-type electrochemical immunosensor was fabricated based on Fe3O4 nanoflowers (Fe3O4 NFs) and heterogeneous chain reaction (HCR) signal amplification strategy for the sensitive detection of hepatitis B surface antigen (HBsAg). The aldehyde-functionalized Fe3O4 NFs are used as a supporting matrix to immobilize the hepatitis B surface antibody 1 (HBsAb1). The biotin-modified single-strand DNA (biotin-SO) was connected onto the biotin-HBsAb2 via linkage of streptavidin (SA), followed by addition of methylene blue (MB) modified single strand DNA1 (MB-S1) and DNA2 (MB-S2) for HCR signal amplification. The designed immunosensor exhibited a detection linear range of 0.5 pg mL(-1)-0.25 ng mL(-1) and a low detection limit of 0.16 pg mL(-1), with excellent stability, selectivity and reproducibility. Furthermore, HBsAg is detected in the serum samples with a stable and fast response, indicating that the proposed immunosensor has a promising potential application in clinical analysis.
Natural protein-templated fluorescent gold nanoclusters: Syntheses and applications
Authors: Guo, Yahui; Amunyela, Helena T. N. N.; Cheng, Yuliang; Xie, Yunfei; Yu, Hang; Yao, Weirong; Li, Hung-Wing; Qian, He
For the past decades, the synthesis of metal nanoclusters has been a great interest for research, for their unique physicochemical properties and great contributions to the catalytic, electrical and biomedical applications. Protein-templated gold nanoclusters (AuNCs) is a kind of fluorescent nanomaterials with good solubility, excellent stability, biocompatibility, decent quantum yields and active groups (-COOH, -NH2) for facilitating modifications. Natural proteins are easily available, commercially affordable, diverse and multitudinous in animals, plants and foods, which provide a template pool for the exploration of AuNCs. This is one of the few reviews of specifically focusing on the natural protein-templated fluorescent AuNCs. The syntheses, properties and applications of different AuNCs were enumerated. Prospects were given on utilizing structure-modified proteins, bioactive enzymes, antibodies which should endow the AuNCs more favourable fluorescence performances and functional characteristics. The applications of AuNCs in analytical, biomedical and food sciences would be further heightened.