Fig 1.
The preparation process of PS-SA.
Fig 2.
Schematic diagram of (a) the synthesis of bio-Ab1 and Ru-Ab2; (b) immuno-sandwich complex (PS-SA/bio-Ab1/CEA/Ru-Ab2) and (c) molecular structures of the Ru-COOH dyes.
Fig 3.
Low magnification SEM images of (a) PS seed particles; (c) PS-M; high magnification SEM images of (b) porous PS-NO2; (d) PS-M; (e) PS-HPG; (f) PS-SA.
Fig 4.
FTIR spectra curves of (a) porous PS microspheres, (b) PS-NO2, (c) PS-M, (d) PS-HPG, (e) PS-tosyl and (f) PS-SA.
Fig 5.
(a) TG curves of PS-M and PS-SA; (b) Magnetization curves of PS-M and PS-SA measured at 298K.
Insets: the photographs of PS-SA before and afer magnetic separation by an extemal magnet.
Fig 6.
Zeta potential results of porous PS microspheres, PS-NO2, PS-M, PS-HPG, PS-tosyl and PS-SA.
Fig 7.
Calibration curve of ECL intensity (a) full range concentration and (b) low concentrations of CEA (ng/mL).
(c) The blank sample was measured repeatedly 20 times.
Table 1.
The mean value (CM) and standard deviation (SD) of the blank sample measured repeatedly 20 times.
Table 2.
The comparison of the linear range and detection limit reported method with that of the developed method for the determination of CEA.
Fig 8.
(A) Specificity investigations of the immunosensor for CEA detection.
(a) blank, (b) AFP (300 ng/mL), (c) CA199 (100 U/mL), (d) TSH (50 uIU/mL), (e) PSA (50 ng/mL), (f) CEA (30 ng/mL), (g) CEA (30 ng/mL) + AFP (300 ng/mL), (h) CEA (30 ng/mL) + CA199 (100 U/mL), (i) CEA (30 ng/mL) + TSH (50 uIU/mL), (j) CEA (30 ng/mL) + PSA (50 ng/mL). (B) Thermostability of the PS-SA beads for the detection at 15 ng/mL of CEA. (C) Reproducibility studies of the immunosensor at 5, 100 and 1000 ng/mL of CEA. (D) The batch-to-batch differences in the electrochemiluminescence detection results among the three independent batches of magnetic beads (PS-SA1, PS-SA2, and PS-SA3).
Fig 9.
The impact of different matrices (artificial serum and PBS) on ECL intensity.
Table 3.
Comparison of detection results from simulated artificial serum samples using homemade reagents and Elecsys CEA reagent kit.