背景:蛇毒毒素(STX)是毒性最强的海洋毒素,这可能会对人类健康造成一些不利影响。灵敏度高,快速反应,和STX污染的低成本检测对于减少渔业和海鲜行业的损失具有重要意义。在各种类型的生物传感器中,电化学生物传感器在STX的检测中得到了广泛的研究,但是电极表面改性材料容易脱落,导致不稳定的电化学信号和较差的再现性。必须有一个用于STX的比率电化学生物传感器。
结果:在这项研究中,我们开发了一种新型的基于适体的电化学传感器(AECs),用于基于用适体修饰的K3Fe(CN)6调节的银纳米颗粒(AgNPs)的STX的灵敏检测。通过将适体固定在AgNP表面上构建AECs。在优化条件下,AECs在0.04~0.15μM范围内对STX呈线性响应,回归方程为Y=-8.0+233.7X(R2=0.9956).检测限(LOD)计算为1nM(基于3N/S),显著低于海鲜中STX的监管限值。此外,AEC表现出优异的灵敏度,重现性和稳定性,以及在可接受的回收率范围为71.2%至93.8%的样品中的检测,在海鲜样品中STX的检测中具有广阔的应用前景。
结论:这项工作提出了一种AECs以实现对STX的灵敏检测。引入K3Fe(CN)6刻蚀AgNPs的反应体系,并将其用作信号源,以避免电化学信号的不稳定性,可以产生比率电化学信号输出模式,提高STX电化学检测的稳定性和灵敏度。
BACKGROUND: Saxitoxin (STX) is the most toxic marine toxin, which can pose several adverse effects on human health. High sensitivity, fast response, and low-cost detection of STX contamination are of significance to reducing the fishery and seafood industries\' loss. Among the various types of biosensors, the electrochemical biosensors have been extensively studied in the detection of STX, but the electrode surface modification material is easy to fall off, resulting in unstable electrochemical signals and poor reproducibility. It is imperative to have a ratiometric electrochemical biosensor for STX.
RESULTS: In this study, we developed a novel aptamer-based electrochemical sensor (AECs) for the sensitive detection of STX based on a K3Fe(CN)6 regulated silver nanoparticles (Ag NPs) modified with aptamer. The AECs was constructed by immobilizing aptamer on Ag NPs surfaces. Under optimized conditions, the AECs showed a linear response towards STX in the range from 0.04 to 0.15 μM with the regression equation of Y = -8.0 + 233.7 X (R2 = 0.9956). The limit of detection (LOD) was calculated to be 1 nM (based on 3 N/S), which is significantly lower than the regulatory limits for STX in seafood. Moreover, the AECs showed excellent sensitivity, reproducibility and stability, as well as the detection in samples with acceptable recovery ranged from 71.2 % to 93.8 %, demonstrating its broad application prospects in detection of STX in seafood samples.
CONCLUSIONS: This work proposed an AECs to achieve sensitive detection of STX. A reaction system of K3Fe(CN)6 etched Ag NPs was introduced and used as the signal source to avoid the instability of the electrochemical signal, which can produce a ratiometric electrochemical signal output mode, improving the stability and sensitivity of electrochemical detection of STX.