High sensitivity detection of human serum albumin using a novel magnetoelastic immunosensor

In this paper, a novel and wireless magnetoelastic (ME) immunosensor for human serum albumin (HSA) detection is presented. Gold nanoparticles layer on the sensor surface can enhance its biocompatibility, stability and sensitivity. The anti-HSA IgG, as a capture probe, was immobilized on the gold-plated ME sensor surface to specifically recognize the target HSA. The binding complex accumulated on the immunosensor surface leads to a decrease in the immunosensor's resonance frequency, corresponding to the HSA concentrations. The atomic force microscopy, the Raman spectrum and the X-ray electron spectroscopy were used to confirm that the antibody immobilization was successful. Furthermore, to enhance its sensitivity, the working concentration of the antibody was optimized to be 25 mu gml(-1). The experimental results demonstrated that the immunosensor exhibited a linear response to the logarithm of HSA concentrations ranging from 0.01 to 100 mu gml(-1), with the sensitivity of 9.3Hz/gml(-1) and the detection limit of 0.01 mu gml(-1), which is significantly lower than the minimum diagnosis limit of urine microalbumin.