Role of magnetic Fe3O4 graphene oxide in chemiluminescent aptasensors capable of sensing tumor markers in human serum

Using pi-pi stacking interaction between magnetic Fe3O4 graphene oxide nanoparticles and impurities (e.g., biomolecules, free prostate specific antigen (PSA) aptamer-conjugated TEX615 that does not bind with PSA) in human serum, a rapid aptasensor with 1,1'-oxalyldiimidazole chemiluminescence (ODI-CL) detection was developed for the quantification of PSA, a tumor marker. The complexes, PSA bound with PSA aptamer-conjugated TEX615, were formed in human serum while the mixture (1 : 1 volume ratio) of PSA in 25% human serum diluted in Tris-HCl buffer (pH 7.5) and PSA aptamer-conjugated TEX615 in Tris-HCl buffer was incubated for 30 minutes. After the incubation, the impurities capable of reducing the efficiency of the aptasensor were removed using magnetic Fe3O4 graphene oxide nanoparticles. With the addition of ODI CL reagents (e.g., ODI, H2O2), finally, PSA in each sample was quantified within 1 second. The sensitivity of the aptasensor with good accuracy, precision, and recovery was as good as those of enzyme immunoassays with absorbance and chemiluminescence detections operated using time-consuming procedures such as multiple-time incubation and washing and expensive and intractable antibodies.