Smart DNA Machine for Carcinoembryonic Antigen Detection by Exonuclease III-Assisted Target Recycling and DNA Walker Cascade Amplification

Abstract

A synthetic DNA machine performs quasi-mechanical movements in response to external intervention, suggesting the promise of constructing sensitive and specific biosensors. Herein, a smart DNA walker biosensor for label-free detection of carcinoembryonic antigen (CEA) is developed for the first time by a novel cascade amplification strategy of exonuclease (Exo) III-assisted target recycling amplification (ERA) and DNA walker. ERA as the first stage of amplification generates the walker DNA, while the autonomous traveling of the walker DNA on the substrate-modified silica microspheres as the second stage of amplification produces an ultrasensitive fluorescent signal with the help of N-methylmesoporphyrin IX (NMM). The DNA machine as a biosensor could be applied for transducing and quantifying signals from isothermal molecular amplifications, avoiding the complicated reporter elements and thermal cycling. The present biosensor achieves a detection limit of 1.2 pg·mL within a linear range of 10 pg·mL to 100 ng·mL for CEA, along with a favorable specificity. The practical applicability of the biosensor is demonstrated by the detection of CEA in human serum with satisfactory results; thus, it shows great potential in clinical diagnosis.

Clinical Significance of Preoperative Serum CEA, CA125, and CA19-9 Levels in Predicting the Resectability of Cholangiocarcinoma

“…For CEA, the AUC was 0.66, and the optimal cut-off was 2.6 g/mL; the sensitivity of CEA in predicting the resectability was 79.0%, along with a specificity of 48.0%, PPV of 75.5%, and NPV of 53.0%. However, CEA is a broad-spectrum tumor marker and cannot be used as a specific marker for the diagnosis of a malignancy [47, 48]. Therefore, the value of serum CEA in predicting the resectability of cholangiocarcinoma was lower than that of CA19-9 and CA125.…”

A bipedal DNA nanowalker fueled by catalytic assembly for imaging of base-excision repairing in living cells

“…[10][11][12] DNA walkers traversing three-dimensional (3D) tracks confer increased capacity in mimicking complicated biological systems and achieving efficient signal amplication. This advantage has spurred the interest in DNA walkers with 3Dtracks along surfaces of nano-and micro-materials, including carbon nanotubes, 13 microparticles, 14,15 and gold nanoparticles (GNPs or AuNPs). [16][17][18] A prominent example is a DNA walker that uses catalytic hairpin assembly (CHA) to drive walking on DNAcoated microparticle surfaces, allowing amplied microRNA (miRNA) detection.…”

Single-step and ultrasensitive detection of carcinoembryonic antigen based on an aptamer transduction-mediated exonuclease III-assisted dual-amplification strategy

“…† In addition, this single-step detection strategy had a dramatically shorter incubation time in comparison with most of the previously reported amplication strategies. 26,27,[35][36][37] Specicity and reproducibility of this developed strategy…”