Title:A Label-Free Fluorescent AND Logic Gate Aptasensor for Carbohydrate
Antigen 15-3 Detection Based on Graphene Oxide
Volume: 25
Issue: 4
Author(s): Wenxiao Hu, Yafei Dong*, Luhui Wang, Yue Wang, Mengyao Qian and Sunfan Xi
Affiliation:
- College of Life Science, Shaanxi Normal University, Xi’an,China
- School of Computer Sciences, Shaanxi Normal
University, Xi’an, P.R. China
Keywords:
DNA logic gate, CA15-3, G-quadruplex, graphene oxide, label-free detection, fluorescence biosensor.
Abstract: Background: Molecular logic gate always makes use of fluorescent dyes to realize
fluorescence signals. The labeling of the fluorophore is relatively expensive, resulting in low yield,
and singly labeled impurities affect the affinity between the target and the aptamer. Label-free
fluorescent aptamer biosensor strategy has attracted widespread interest due to lower cost and
simplicity.
Objective: Herein, we have designed an AND logic gate fluorescent aptasensor for detecting
carbohydrate antigen 15-3(CA15-3) based on label-free fluorescence signal output.
Materials and Methods: A hairpin DNA probe consists of CA15-3 aptamer and partly anti-CA15-
3 aptamer sequences as a long stem and G-rich sequences of the middle ring as a quadruplexforming
oligomer. G-rich sequences can fold into a quadruplex by K+, and then G-quadruplex
interacts specifically with N-methylmesoporphyrin IX(NMM), leading to a dramatic increase in
fluorescence of NMM. With CA15-3 and NMM as the two inputs, the fluorescence intensity of the
NMM is the output signal. Lacking CA15-3 or NMM, there is no significant fluorescence
enhancement, and the output of the signal is “0”. The fluorescence signal dramatically increases
and the output of the signal is “1” only when CA15-3 protein and NMM are added at the same
time.
Results: This biosensor strategy was observed to possess selectivity and high sensitivity for detecting
CA15-3 protein from 10 to 500 U mL-1 and the detection limit was found to be 10 U mL-1, which also
showed good reproducibility in spiked human serum.
Conclusion: In summary, the proposed AND logic gate fluorescent aptasensor could specifically
detect CA15-3.