School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China.
The School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, China.
Anal Chim Acta. 2021 Oct 9;1181:338908. doi: 10.1016/j.aca.2021.338908. Epub 2021 Aug 4.
Heavy metals are considered as hazardous substances to human because of their toxicity, persistence and bioaccumulation, and the level in serum is an important factor to evaluate the caused health risk, which depends on efficient and sensitive analytical methods. Here, a triple signal-amplified electrochemical sensing platform based on metal-dependent DNAzymes was fabricated for sensitive determination of heavy metals in serum (copper as a model target). Under the optimized conditions, the proposed method showed good sensitivity (limit of detection, 0.33 fM for Cu) with excellent selectivity and stability, which is ascribed to: (i) tetrahedral DNA nanostructures (TDNs) that was used as a promising scaffold to adjust the selective transformation between heterogeneous and homogeneous reactions, preventing the nonspecific binding of electrodes surface and DNA probes; (ii) the magnetic beads (MBs) used which led to signal amplification and decreased background owing to its excellent properties of extracting equivalent targets from the complex samples; (iii) two signal amplification strategy of catalytic hairpin assembly (CHA) and hybridization chain reaction (HCR). In addition, the proposed sensing platform displayed satisfactory accuracy through the validation with inductively coupled plasma-mass spectrometry (ICP-MS) and a spike-recovery analysis (recoveries, 87.92-111.61%; RSD, 4.89-8.85%), indicating the great potential for rapid and sensitive detection of Cu or other metal ions.
重金属因其毒性、持久性和生物累积性而被认为对人类是有害的物质，而血清中的水平是评估所造成的健康风险的一个重要因素，这取决于高效和敏感的分析方法。在这里，我们基于金属依赖型 DNA 酶构建了一种三重信号放大电化学传感平台，用于灵敏地测定血清中的重金属（以铜作为模型靶标）。在优化条件下，该方法表现出良好的灵敏度（铜的检测限为 0.33 fM），具有优异的选择性和稳定性，这归因于：（i）四面体 DNA 纳米结构（TDN），它被用作一种很有前途的支架，以调节异质和同质反应之间的选择性转化，防止电极表面和 DNA 探针的非特异性结合；（ii）使用了磁性珠（MBs），由于其从复杂样品中提取等效靶标的优异性能，导致信号放大和背景降低；（iii）催化发夹组装（CHA）和杂交链式反应（HCR）的两种信号放大策略。此外，通过与电感耦合等离子体质谱（ICP-MS）和加标回收分析（回收率为 87.92-111.61%，RSD 为 4.89-8.85%）的验证，该传感平台显示出令人满意的准确性，表明其具有快速灵敏检测 Cu 或其他金属离子的巨大潜力。
