Surface acoustic wave immunosensors based on immobilized C60-proteins

Fullerene C60-proteins, C60-hemoglobin (C60-Hb) and C60-myoglobin (C60-Mb), were prepared and applied in surface acoustic wave (SAW) immunosensors to detect the anti-hemoglobin (anti-Hb) and anti-myoglobin (anti-Mb) antibodies, respectively, in aqueous solutions. The immobilizations of Hb and Mb onto fullerene were studied through a C60-coated SAW sensor system in liquid. The partially irreversible responses of these proteins were observed by the desorption study, which implied that fullerene could chemically react with these proteins. Both C60-Hb and C60-Mb coating materials were successfully prepared and identified with an FTIR spectrometer. The C60-protein-coated SAW immunosensors exhibited linear frequency responses to the concentrations of anti-Hb and anti-Mb antibodies with sensitivities of 0.14 and 1.27 kHz/(μg/mL), respectively. Both C60-protein-coated SAW immunosensors showed detection limits of 0.32 and 0.035 μg/mL for anti-Hb and anti-Mb antibodies, respectively. The optimum pH and temperature on the frequency response of the anti-Hb SAW immunosensor were also observed to be at 7.3 and 27 °C, respectively. The interference of various common bio-species in human blood, e.g. urea, ascorbic acid, tyrosine, and metal ions, to the SAW immunosensor coated with C60-Hb was investigated. These common bio-species interferences showed nearly no interference to the SAW immunosensors coated with C60-Hb. The reproducibility and lifetime of these SAW immunosensors immobilized with C60-proteins were also investigated and discussed. Dual-channel SAW immunosensors coated with C60-Hb and C60-Mb were applied to detect anti-Hb and anti-Mb simultaneously.