A portable colorimetric biosensor using MOF-Pt@Cu for Salmonella detection

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Food Safety

Background:

• Bacterial contamination, particularly Salmonella, poses a significant threat to public health and food safety.
• Current detection methods often lack the sensitivity, speed, or portability required for effective field applications.
• Development of advanced nanomaterials and integrated systems is crucial for overcoming these limitations.

Purpose of the Study:

• To develop a novel, highly sensitive, and rapid detection platform for Salmonella using bimetallic nanozymes integrated with immunomagnetic beads.
• To evaluate the performance of the developed system in terms of sensitivity, specificity, and reliability in complex food matrices.
• To create a portable, user-friendly device for on-site Salmonella detection.

Main Methods:

• Synthesis of a bimetallic nanozyme (Pt/Cu-loaded MOF, MOF-Pt@Cu) with enhanced peroxidase-like activity.
• Integration of the nanozyme with immunomagnetic beads (IMB) for efficient capture and concentration of Salmonella.
• Development of a low-cost, portable detection instrument coupled with smartphone data analysis.
• Validation of the method using spiked milk and chicken samples.

Main Results:

• The MOF-Pt@Cu nanozyme exhibited significantly enhanced peroxidase activity and stability.
• The integrated IMB-nanozyme system achieved a low detection limit of 2.4 CFU/mL for Salmonella.
• High average recoveries (105.59% in milk, 102.17% in chicken) with low relative standard deviations (≤5.80%) demonstrated reliability.
• The portable device provided real-time data and accurate bacterial concentration conversion via smartphone.

Conclusions:

• The novel bimetallic nanozyme-based immunomagnetic bead assay offers a highly sensitive and rapid method for Salmonella detection.
• The developed portable system is reliable, practical, and suitable for field-deployable pathogen screening.
• This approach holds significant potential for improving food safety and public health surveillance.