Fig 1.
Photographs of the fabricated micro devices.
(A) The MEMS-fluxgate sensor. (B) The Au film substrates (5×3 mm2).
Fig 2.
AFM images and roughness analysis of the modified Au film.
(A) The blank Au film. (B) The Au film after 11-MUA modification. (C) The Au film after antibody modification.
Fig 3.
Immunoassay and detection method for CRP based on our system.
(A) The immunoassay process of CRP. (B) Illustration of the detection method based on fluxgate sensor (C) The photograph of the fluxgate sensing circuit-system, the inlet shows the illustration of the relative position of the CRP sample in relation to the sensor. (D) CRP-labeled Dynabeads detection mechanism of the proposed system.
Fig 4.
SEM images of immobilized CRP-bead labels of different CRP concentration samples.
(A) 0.002 μg/mL. (B) 0.005 μg/mL. (C) 0.01 μg/mL. (D) 0.1 μg/mL. (E) 1 μg/mL. (F) 10 μg/mL.
Fig 5.
Detection sensitivity for CRP.
(A) Full view of the output voltage towards different CRP concentration. (B) The partial enlargement of the field range corresponding to 250–370 μT.
Fig 6.
Linear range for the CRP detection with applied He = 330 μT.
Fig 7.
Reproducibility and stability test.
(A) Reproducibility of the proposed biosystem to detect various CRP concentrations. (B) Stability test of the system with respect to 1 μg/mL CRP.
Fig 8.
Specificity investigations of the biosystem.
(A) Blank. (B) AFP (0.02 μg/mL). (C) CEA (0.02 μg/mL). (D) CRP (0.002 μg/mL). (E) CRP (0.002 μg/mL) +AFP (0.02 μg/mL). (F) CRP (0.002 μg/mL) + CEA (0.02 μg/mL).
Table 1.
Comparison of different immunosensors for CRP detection.