A universal assay strategy for sensitive and simultaneous quantitation of multiplex tumor markers based on the stirring rod-immobilized DNA-LaMnO₃ perovskite-metal ions encoded probes

It was extremely urgent to develop some simultaneous and sensitive biosensors for detecting multiplex serum tumor markers (TMs) for early screening of cancers. Herein, a multiplex assay was developed based on the DNA-LaMnO₃ (DNA-LMO) perovskite encoded probes and targets mediated competitive replacement strategy. Alpha fetoprotein (AFP), carcinoembryonic antigen (CEA) and prostate specific antigen (PSA) markers were employed as representative target TMs. Aptasensor is prepared by a series of DNA-LMO-M encode probes which were prepared by three hyperbranched DNA firstly immobilized on LMO encapsulating Pb, Cd or Cu ions. Then, three TMs aptamers were labeled on the stirring-rod and hybridized with the probes. After the developed encoded probes was incubated the TMs, the encoded probes corresponding to different TMs can be released into the supernatant through the competitive replacement. The inner metal ion can be simultaneously detected by square wave voltammetry corresponding to various TMs. Since the stirring rod can enrich many encoded probes containing a lot of metal ions, multiplex signal amplification can be realized. Due to the enrichment and easy separation of the stirring rod, the signal-to-noise ratio was also obviously improved and thus to results in good sensitivity and accuracy. Moreover, it took only 20 min to detect three targets which much faster than many same types of aptasensor. Under the optimal conditions, the low detection limit for CEA (3.6 × 10^-4 ng/mL), AFP (3.4 × 10^-4 ng/mL) and PSA (2.8 × 10^-4 ng/mL) were obtained. Therefore, this method is likely to be used for early and sensitive screening of tumors.