Phenylboronic acid decorated SiO2@Fe3O4 magnetic nanoparticle coupled with peroxidase-like Au,Pt,Cu@polydopamine immunoprobe based sandwich approach for the detection of transferrin.

Transferrin (TRF) is the main iron-containing protein in plasma, responsible for carrying iron from digestive absorption and released from the erythrocyte degradation. The plasma TRF levels can be used to diagnose anemia and monitor treatment. Herein, a sandwich type biosensor was developed for the sensitive and efficient TRF detection utilizing the affinity of boronic acid and specific recognition of antibody. TRF can be captured by the facilely synthesized phenylboronic acid decorated SiO2@Fe3O4 magnetic nanoparticle (PBA-SiO2@Fe3O4), and then the antibody functionalized Au,Pt,Cu@polydopamine (Ab-Au,Pt,Cu@PDA) with peroxidase-like activity was bond to TRF to form the sandwich conjugate. After the prompt magnetic separation and catalysis with the chromogenic substrates (TMB and H2O2), the distinct color development can be observed and measured for the TRF quantification. The proposed method shows satisfied performance with a detection range of 0.128-2000 ng/mL and LOD of 0.051 ng/mL. Moreover, this approach possesses excellent stability and simple operation, without complicated sample pretreatment. Consequently, this biosensor poses a significant potential for the diagnosis and monitoring of abnormal TRF levels-related diseases.