Dual-modal improved biosensing platform for sugarcane smut pathogen based on biological enzyme-Mg²⁺ DNAzyme coupled...

Sugarcane smut is a major disease affecting the yield and quality of sugarcane, and its early detection is crucial for the healthy development of sugarcane industry. In this work, a dual-modal biosensing platform is designed based on Au-V-MOF and 3D DNA walker for highly sensitive and precise detection of the sugarcane smut pathogen. This detection system utilizes the catalytic properties of biocatalysts and the precise cleavage of DNAzymes, along with 3D DNA walker nanotechnology and a designed "walking track", to achieve amplified detection signals and accurate target recognition. The detection platform utilizes catalytic hairpin assembly for target recycling. Output strand T1 interacts with DNAzyme via a 3D transporter, cleaving S1 in Mg²⁺ presence. This triggers cascading hybridization chain reaction to form long double-stranded DNA structures that absorb substantial methylene blue (MB). This amplifies the electrical signal and causes a proportional color change due to the redox reaction of MB, which enables electrochemical and colorimetric detection of the target. The method shows a linear response range from 0.0001 to 10,000 pM with a detection limit of 56.76 aM (S/N = 3). It features high sensitivity, specificity, and accuracy, which offers significant potential for early warning and precise detection of sugarcane smut.