Ming Li,Weipeng Teng,Wenying Lu,Mingna Sun,Jinsheng Duan,Xuchun Qiu
The improvement of dual-mode techniques was of particular interest to researchers, which might enhance the detection performance and applicability. Here, a dual-mode optical aptasensor (DO-aptasensor) platform based on exonuclease I (Exo I) cyclic digestion and synergistic enhancement strategy had proposed for zearalenone (ZEN). Following the preparation of dumbbell-shaped signal probe, the Exo I-based cyclic digestion amplification performed, and then the synergistic enhancement effect carried out to achieve the Poly-HRP-based colorimetry and FAM-SGI-based fluorescence. The efficient homogeneous system realized through the magnetic separation, while the signal interference further eliminated by the graphene oxide (GO). The LOD values were as low as 0.067 ng mL −1 for colorimetry mode and 0.009 ng mL −1 for fluorescence mode, which reduced 23-fold and 172-fold than ELASA by same ZEN-Apt. This promising platform gave rise to a dual-mode optical readout, improved sensitivity and positively correlated detection. Meanwhile, the DO-aptasensor also exhibited the acceptable specificity, desirable reliability and excellent practicability. This novel avenue of aptasensor platform hold great potential for dual-mode optical monitoring of other targets, which can further expand the application scope of Exo I-based signal amplification and synergistic enhancement effect.
The establishment of a highly sensitive and efficient platform for detecting circulating miRNA in serum is important for disease diagnosis and prognosis. To this end, a self-assembled horseradish peroxidase (HRP)-based polymer (poly-HRP) dual signal amplification strategy, via skillful combination of functionalized magnetic nanoparticles as the capture nanoprobes and the poly-HRP as signal amplification probes, has been developed for highl-sensitive and accurate detection of circulating miR-142-3p in human serum. Just by mixing building blocks together at one time, the poly-HRP used for dual signal amplification can be engineered by only one-step assembly. As the poly-HRP can be directly prepared ahead, avoiding chain amplification reaction in the detection process, the assay can be rapidly accomplished in about one hour. The measured limit-of-detection (LOD) is down to 100 fM. Standard miR-142-3p spiked in human serum is measured with ideal recovery rates ranging from 97.46% to 115.90%. More importantly, this method was validated to be applicable to direct detection of miR-142-3p in serums, and the results suggested that the miR-142-3p levels of serum samples obtained from T-cell acute lymphoblastic leukemia children (n = 25) are significantly higher than those from healthy control groups (n = 25) ( P < 0.01). To conclude, the ingenious combination of functionalized magnetic nanoparticles and the poly-HRP presented in this work brings forth a rapid, convenient, yet simple, sensitive, and specific biosensing method that can potentially be applied for clinical diagnosis.
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