PNIPAAm-functionalized flexible microchip for rapid detection of surface microbial contaminants

Area of Science:

• Microfluidics
• Biosensing
• Surface Science

Background:

• Surface microbial contamination poses significant challenges in detection due to lengthy processes.
• Current methods often involve disconnected sampling and detection steps, increasing time and complexity.

Purpose of the Study:

• To develop an integrated microfluidic system for simultaneous bacterial sampling, transfer, concentration, and detection.
• To overcome the limitations of conventional methods by providing a rapid and efficient solution for surface microbial analysis.

Main Methods:

• An innovative microfluidic chip was designed using a thermos-responsive poly(N-isopropylacrylamide) (PNIPAAm) gel micropillar array for bacterial capture and release.
• A polydimethylsiloxane (PDMS) cover with a canopy-shaped microchannel facilitated sequential bacterial transport, fluorescent labeling, and in situ detection.
• Staphylococcus aureus (S. aureus) was used as a model organism to validate the system's performance.

Main Results:

• The system achieved high sampling (75.6%) and elution (88.4%) efficiencies for S. aureus on stainless steel.
• A low detection limit of 5.15 × 10^3 CFU/cm^2 was demonstrated.
• The entire detection process was completed in under 45 minutes, representing a 32-fold reduction in processing time compared to traditional methods.

Conclusions:

• The integrated microfluidic system offers a rapid, efficient, and comprehensive solution for surface microbial contaminant detection.
• This technology holds significant promise for applications in food safety, medical hygiene, and environmental monitoring.
• The platform streamlines the detection process, minimizing sample handling and analysis time.