Label-Free Fluorescence Detection of Carbohydrate Antigen 15-3 via DNA AND Logic Gate Based on Graphene Oxide

In this work, we have developed a DNA AND logic gate based on graphene oxide (GO) absorbing single DNA and G-quadruplex interacting with N-methyl mesoporphyrin IX(NMM) for detecting breast cancer biomarker carbohydrate antigen 15-3 (CA15-3). With CA15-3 and NMM as the two inputs, the fluorescence intensity of the NMM is the output signal. A hairpin DNA probe is designed, consisting of CA15-3 aptamer and partly anti-CA15-3 aptamer sequences as a long stem and G-rich sequences as a quadruplex-forming oligomer. In the presence of CA15-3 or NMM alone, there is no significant fluorescence enhancing, and the output of the signal is “0”. While in the presence of CA15-3 protein and NMM, the fluorescence signal was dramatically increasing and the output of the signal is “1”. This biosensor platform also exhibited good reproducibility, selectivity and showed high sensitivity for CA15-3 protein in a range of 10U/mL-500U/mL with the detection limit of 10U/mL. In addition, the fluorescence DNA AND logic gate can successfully be applied to the determination of CA15-3 in spiked human serum. In summary, the proposed fluorescent DNA AND logic gate could construct a simple, fast, label-free and highly specific sensing methods for CA15-3.