DNAzyme biosensors: Frontiers in design, clinical applications, performance optimization, and future perspectives

DNAzymes are catalytic single-stranded DNA molecules that integrate the programmability and stability of nucleic acids with enzyme-like activity. These attributes make DNAzymes ideal candidates for use as recognition and signal-amplification elements in next-generation biosensors. They offer high specificity, design flexibility, and cost-effective production. This review provides a systematic analysis of DNAzyme biosensors. It begins with their fundamental design principles and core classifications, detailing the modular logic of target recognition, catalytic activation, and signal transduction. Subsequently, we summarizes their advanced diagnostic applications. These include the highly sensitive detection and live-cell imaging of tumor biomarkers, the specific identification of pathogens, and the dynamic monitoring of intracellular metal ions. Finally, the review discusses performance optimization strategies, such as advanced signal amplification cascades, stability-enhancement modifications, and anti-interference nanodevice designs. By synthesizing current challenges with emerging solutions, we present a future outlook for DNAzyme technology, from engineered molecular tools to intelligent, cell-integrated systems, and highlight its transformative potential for precision medicine and on-site testing.