Hook-Like DNAzyme-Activated Autocatalytic Biosensor for the Universal Detection of Pathogenic Bacteria

Area of Science:

• Biotechnology
• Molecular Biology
• Biosensors

Background:

• DNAzyme-based assays are useful for detecting pathogenic bacteria but often lack sensitivity and specificity.
• Existing signal amplification methods require extensive modifications, limiting their use for detecting a wide range of bacteria.

Purpose of the Study:

• To develop a novel, universal platform for pathogenic bacteria detection using a DNAzyme-activated autocatalytic nucleic acid circuit.
• To enhance the sensitivity and specificity of DNAzyme-based assays through exponential signal amplification.

Main Methods:

• A hook-like connector DNA was designed to integrate DNAzymes with isothermal, enzyme-free autocatalytic hybridization chain reaction and catalytic hairpin assembly.
• This circuit enables exponential signal amplification from DNAzyme recognition events.
• The platform's universality was demonstrated by modifying the connector DNA to detect various pathogenic bacteria.

Main Results:

• The biosensor showed a linear response from 1.5 × 10^3 to 3.7 × 10^7 CFU/mL with a detection limit of 1.3 × 10^3 CFU/mL.
• The platform successfully detected *Escherichia coli*, *Staphylococcus aureus*, *Klebsiella pneumoniae*, and *Salmonella typhimurium*.
• Signal amplification significantly improved the specificity of DNAzyme-based bacterial detection.

Conclusions:

• The hook-like DNAzyme-activated autocatalytic platform offers a versatile, sensitive, and specific approach for pathogenic bacteria detection.
• This innovative circuit overcomes inherent DNAzyme sensitivity limitations.
• The platform holds promise for expanding DNAzyme applications in bacteria detection.