Low fouling strategy of electrochemical biosensor based on chondroitin sulfate functionalized gold magnetic particle for voltammetric determination of mycoplasma ovipneumonia in whole serum

Based on the successful design and preparation of Fe 3 O 4 @ [email protected] glycol (PEG)@chondroitin sulfate (CS) nanoparticles , a novel electrochemical biosensor was elaborately developed for MO determination by the drop coating method. This biosensor demonstrates ultra-low fouling properties in complex biological systems, especially in whole serum. Only 2.40% of the differential pulse voltammetry (DPV) signal changes are shown in the resistance test of electrode interface to 100% goat serum. The constructed biosensor also presented a good selectivity (DNA samples for M1, M2 and M3give a response around 14.2–21.4%of that obtained by the target analyte), reproducibility (the relative standard deviation (RSD) is only 4.82%) and storage stability (93.2% of the initial response is maintained after 20 day). Moreover, this biosensor exhibits high analytical performance with a wide line arranges (10 −17  M ∼ 10 −12  M) in buffer, even in 100% goat serum. In both cases, a low limit of detection (LOD) of 3.3 aM(S/N = 3)is showed. To our knowledge, a few examples reported the application of electrochemical biosensors to the direct ultrahigh sensitive determination of MO, especially in whole serum.