A Capillary Flow Dynamics-Based Sensing Modality for Direct Environmental Pathogen Monitoring

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Materials Science

Background:

• Development of simple, field-deployable biosensors is crucial for rapid environmental and health monitoring.
• Existing biosensing technologies often face limitations in terms of complexity, cost, and on-site applicability.
• Interfacial property changes and fluid dynamics offer potential for novel biosensing mechanisms.

Purpose of the Study:

• To develop an ultra-simple and field-ready biosensor assay transducer mechanism.
• To leverage interfacial property changes and capillary flow dynamics for pathogen quantification.
• To demonstrate the applicability of this mechanism for detecting Escherichia coli and Zika virus.

Main Methods:

• Utilized antibody-conjugated submicron particle suspensions and their interfacial property changes.
• Employed a paper-based microfluidic device to observe differential capillary flow.
• Developed flow models incorporating interfacial and rheological properties to correlate flow rate with target-particle aggregation.

Main Results:

• Demonstrated tunable differential capillary flow for pathogen quantification.
• Established a significant relationship between flow rate and interfacial effects due to target-particle aggregation.
• Achieved very low limits of detection: 1 log CFU/mL for Escherichia coli K12 and 20 pg/mL for Zika virus (ZIKV).
• Assays completed within an operating time of 30 seconds.

Conclusions:

• The novel assay transducer mechanism shows significant promise for environmental and health monitoring applications.
• The developed biosensor offers rapid, sensitive, and field-deployable pathogen detection.
• This approach provides an ultra-simple platform for point-of-care diagnostics and water quality assessment.