Dual nanozyme-powered self-sensing platform with cascaded amplification for ultrasensitive detection of sugarcane...

Early detection of Fusarium sacchari, the causative agent of sugarcane pokkah boeng disease, is critically hindered by the insufficient sensitivity of existing detection methods. This limited sensitivity leads to diagnostic delays, thereby complicating timely disease management and control in sugarcane cultivation. Early and accurate detection is essential to preventing the spread of the disease and minimizing crop loss, thus highlighting the urgent need for innovative diagnostic solutions. These solutions must overcome the limitations of traditional methods, offering more sensitive, reliable, and efficient approaches for early intervention and disease prevention in agricultural practices.

To overcome these limitations, we developed a self-powered electrochemical biosensing platform incorporating a cascaded amplification strategy. This platform utilizes a carbon cloth (CC)-based enzymatic biofuel cell, with a bioanode modified by a dual nanozyme system (AuNPs/Mn₃O₄) coupled with sulfur-doped graphdiyne (S-GDY). This modification significantly enhances glucose oxidation kinetics and electron transfer efficiency, thereby generating robust self-powered signals. The biocathode is functionalized with a DNA probe targeting Fusarium sacchari DNA. Upon binding, a multiplexed localized catalytic hairpin assembly (ML-CHA) triggers rolling circle amplification (RCA), which generates long repetitive DNA sequences. These sequences bind to the probe, inducing structural reconfiguration and amplifying the electrostatic interaction with [Ru(NH₃)₆]³⁺, producing a significantly enhanced open-circuit voltage (E^OCV) signal. This dual nanozyme-based amplification enables ultrasensitive detection with a limit of 40.7 aM and a broad linear range from 0.0001 to 10,000 pM.

This innovative biosensing platform demonstrates superior performance over conventional qPCR methods for detecting Fusarium sacchari in authentic sugarcane samples. Its self-powered nature and portable signal readout enable on-site, rapid diagnostics, offering a powerful tool for agricultural pathogen detection. The platform holds great potential for early disease prevention, offering an efficient solution for managing pokkah boeng disease in sugarcane cultivation.