Surface engineering strategies of gold nanomaterials and their applications in biomedicine and detection.

Gold nanomaterials have potential applications in biosensors and biomedicine due to their controllable synthesis steps, high biocompatibility, low toxicity and easy surface modification. However, there are still various limitations including low water solubility and stability, which greatly affect their applications. In addition, some synthetic methods are very complicated and costly. Therefore, huge efforts have been made to improve their properties. This review mainly introduces the strategies for surface modification of gold nanomaterials, such as amines, biological small molecules and organic small molecules as well as the biological applications of these functionalized AuNPs. We aim to provide effective ideas for better functionalization of gold nanomaterials in the future.

Specifically immobilizing His-tagged allergens to magnetic nanoparticles for fast and quantitative detection of allergen-specific IgE in serum samples.

Fast and accurate detection of specific IgE (sIgE) is essential for diagnosis of allergic diseases. In this study, we developed a nano-capturer Fe3O4@SiO2-NTA based on magnetic nanoparticles with surface modification of Ni-NTA moieties. Results showed that our immunosensor based on the specifically immobilization of recombinant allergen protein on the Fe3O4@SiO2-NTA could realize fast, high efficiency and low-cost detection of sIgEs in serum samples. In vitro experiments demonstrated that the chemiluminescence (CL) response of the immunosensor to sIgEs showed an obviously discrimination between positive and negative serum samples. The CL intensity values were proportional to the sIgE concentrations in the range of 2.52-14.02 ng/mL with detection limit of 0.35 ng/mL, which offered a promising platform for fast and quantitative determination of sIgEs. Furthermore, our method was successfully utilized for allergic disease diagnosis in 46 serum samples and satisfied results were achieved in comparison with the commercial ELISA kit. In particular, by simply changing various recombinant allergen proteins immobilized on the surface of Fe3O4@SiO2-NTA, our strategy showed great potential for high-throughput analysis of allergen screening.