Two microsensors obtained by the physical immobilization of 5,10,15,20-tetraphenyl-21H,23H-porphine (TPP) and 5,10,15,20-tetrakis (pentafluorophenyl chloride)-21H,23H-iron (III) porphyrin (Fe(TPFPP)Cl) in carbon nanopowder decorated with gold nanoparticles (AuNp) were designed, characterized, validated and used for the molecular recognition and simultaneous ultrasensitive determination of CEA, CA15-3 and HER2 in whole blood. High sensitivities were recorded for both microsensors. Low limits of quantification were recorded for all biomarkers: CEA (12.8 pg mL-1 by using Fe(TPFPP)Cl/AuNp, and 190 fg mL-1 by using TPP/AuNp), CA 15-3 (100 fU mL-1 for both microsensors) and HER2 (3.9 fg mL-1 by using Fe(TPFPP)Cl/AuNp, and 35 fg mL-1 by using TPP/AuNp). A very good correlation between the results obtained using the proposed microsensors and ELISA, certified by the Student t-test, proves that the screening test can be used for ultrasensitive assays of the three biomarkers in whole blood.
Keywords: CA15-3; CEA; HER2; nanocarbon; stochastic microsensor.