Abstract：
In this study, an ultrasensitive photoelectrochemical (PEC) aptasensor based on dual-sensitized heterojunction Ag2S/ZnS/NiS composites as a signal probe was proposed for the detection of tobramycin (TOB) by combining a cascaded quadratic signal amplification strategy. Specifically, compared to the limited visible light-harvesting capability of single sensitized composites, Ag2S/ZnS/NiS composites with p-n and n-n heterojunction could greatly improve the light energy utilization to tremendously strengthen the optical absorption in the entire visible-light region. Moreover, dual-sensitized heterojunction could effectively hinder the rapid recombination of photoelectrons and holes (carriers) to obtain a good photocurrent for improving the sensitivity of the aptasensor. Furthermore, a cascaded quadratic signal amplification strategy was applied to convert trace target TOB into plentiful gold nanoclusters (Au NCs) labelled double-stranded DNA for the construction of PEC aptasensor, with a broad linear detection range from 0.01 to 100 ng mL-1 and a low detection limit of 3.38 pg mL-1. Importantly, this study provided a versatile and sensitive PEC biosensing platform for TOB analysis, and demonstrated its successful application for TOB detection in milk samples. This protocol provides a novel dual-sensitized heterojunction composites to develop a highly efficient and harmfulless PEC aptasensor, which is expected to be used in food safety, environmental monitoring and other areas.
摘要：
在这项研究中,提出了一种基于双敏化异质结Ag2S/ZnS/NiS复合材料作为信号探针的超灵敏光电化学（PEC）传感器，通过结合级联二次信号放大策略来检测妥布霉素（TOB）。具体来说,与单一敏化复合材料有限的可见光捕获能力相比，具有p-n和n-n异质结的Ag2S/ZnS/NiS复合材料可以大大提高光能利用率，从而极大地增强整个可见光区域的光吸收。此外，双敏化异质结可以有效地阻碍光电子和空穴（载流子）的快速复合，从而获得良好的光电流，以提高aptasensor的灵敏度。此外，采用级联二次信号放大策略将痕量目标TOB转化为丰富的金纳米簇（AuNC）标记的双链DNA，用于构建PECaptasensor，具有0.01至100ngmL-1的宽线性检测范围和3.38pgmL-1的低检测限。重要的是,这项研究为TOB分析提供了一个通用而灵敏的PEC生物传感平台，并证明了其在牛奶样品中TOB检测中的成功应用。该协议提供了一种新颖的双敏化异质结复合材料，以开发一种高效且无害的PECaptasensor，有望用于食品安全，环境监测等领域。
