Indirect Detection of Bacteria on Optically Enhanced Porous Silicon Membrane-Based Biosensors Using Selective Lytic...

Area of Science:

• Biosensor technology
• Nanomaterials
• Microbiology

Background:

• Traditional biosensors often rely on surface-bound bio-probes for selectivity.
• Porous silicon (PSi) offers unique optical and physical properties for sensing applications.
• Bacterial detection requires sensitive and selective methods, especially in complex samples.

Purpose of the Study:

• To develop a novel biosensor for the indirect detection of bacteria via their lysate.
• To enhance selectivity by incorporating lytic enzymes directly into the assay, rather than relying on surface bio-probes.
• To improve the sensitivity and reduce assay time for bacterial detection.

Main Methods:

• Fabrication of porous silicon membranes using standard microfabrication techniques.
• Coating of PSi sensors with titanium dioxide (TiO2) layers via atomic layer deposition for passivation and optical enhancement.
• Utilizing bacteriophage-encoded PlyB221 endolysin as a lytic agent for targeted bacterial lysis.
• Indirect detection of bacterial lysate by monitoring changes in the optical properties of the PSi membrane.

Main Results:

• The developed TiO2-coated PSi biosensor demonstrated high sensitivity for *Bacillus cereus* detection, reaching 10^3 CFU/mL.
• The assay achieved a total detection time of 1 hour and 30 minutes.
• The biosensor exhibited excellent selectivity and versatility, successfully detecting *B. cereus* in a complex sample matrix.

Conclusions:

• The developed biosensor platform offers a sensitive, selective, and rapid method for indirect bacterial detection.
• The strategy of using lytic enzymes for analyte-specific targeting overcomes limitations of traditional bio-probe based sensors.
• This approach holds promise for various applications requiring efficient bacterial identification.