*Review* **Application of Nanomaterial Modified Aptamer-Based Electrochemical Sensor in Detection of Heavy Metal Ions**

**Zanlin Chen 1, Miaojia Xie 1, Fengguang Zhao <sup>2</sup> and Shuangyan Han 1,\***


**Abstract:** Heavy metal pollution resulting from significant heavy metal waste discharge is increasingly serious. Traditional methods for the detection of heavy metal ions have high requirements on external conditions, so developing a sensitive, simple, and reproducible detection method is becoming an urgent need. The aptamer, as a new kind of artificial probe, has received more attention in recent years for its high sensitivity, easy acquisition, wide target range, and wide use in the detection of various harmful substances. The detection platform that an aptamer-based electrochemical biosensor (E-apt sensor) provides is a new approach for the detection of heavy metal ions. Nanomaterials are particularly important in the construction of E-apt sensors, as they can be used as aptamer carriers or sensitizers to stimulate or inhibit electrochemical signals, thus significantly improving the detection sensitivity. This review summarizes the application of different types of nanomaterials in E-apt sensors. The construction methods and research progress of the E-apt sensor based on different working principles are systematically introduced. Moreover, the advantages and challenges of the E-apt sensor in heavy metal ion detection are summarized.

**Keywords:** heavy metal ions; aptamer; electrochemical biosensor; nanomaterials
