Sensitivity-enhanced self-powered biosensing platform for detection of sugarcane smut using Mn-doped ZIF-67, RCA-DNA...

Sugarcane smut is a widespread fungal disease, which severely impairs the quality and sugar yield of sugarcane. Early detection is crucial for mitigating its impact, which makes the development of a highly sensitive and accurate detection method essential. Herein, the Mn-doped zeolite imidazolate framework (ZIF-67), synthesized via a nano-confined-reactor approach, is designed to significantly enhance electron transport and boost the enzyme loading capacity within biofuel cells, thereby potentially enhancing their overall performance. By integrating rolling circle amplification (RCA) with DNA nano-grid array, an sensitive detection platform is engineered based on biofuel cells that can specifically identify the sugarcane smut gene fragment (bE4'). Upon recognition of the target gene bE4', the arm strands of the locked bridge DNA is triggered to open to initiate a series of reactions. This process not only anchores DNA to the electrode, but also promotes RCA under the catalysis of enzymes to produce long single-stranded DNA to capture DNA nano-grid array. The formation of double-stranded DNA can capture [Ru(NH₃)₆]³⁺ to further amplify the output signal. Furthermore, a capacitor is integrated into the detection system and a 16.7-fold increase in sensitivity is therefore obtained. In the concentration from 10^-4 to 10⁴ pM, the method shows a robust linear response with a detection limit of 34.5 aM (S/N = 3). This work presents a dependable, high-sensitivity and portable detection solution for the early and efficient detection of sugarcane smut, exhibiting great potential for agricultural disease management and monitoring.