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Biosample Concentration Using Microscale Forward Osmosis with Electrochemical Monitoring
Martin K Kimani1, Rachel Loo1, Edgar D Goluch1,2
1Department of Chemical Engineering , Northeastern University , Boston , Massachusetts 02115 , United States.
Analytical Chemistry
|May 10, 2019
Summary
This study presents a microfluidics system using dialysis membranes for concentrating biofluid samples. The novel osmotic system enhances electrochemical signals for pathogen detection, improving diagnostics.
Area of Science:
- Biomedical Engineering
- Analytical Chemistry
- Microfluidics
Background:
- Dialysis membranes are typically used for buffer exchange.
- Current methods for sample concentration lack quantitative inline monitoring.
- Microfluidics offers potential for miniaturized diagnostic systems.
Purpose of the Study:
- To develop and evaluate an integrated microfluidics system for biofluid sample concentration.
- To assess the feasibility of using cellulose ester dialysis membranes for sample concentration.
- To investigate the system's performance in enhancing electrochemical detection of biomarkers.
Main Methods:
- Designed an integrated microfluidics system with cellulose ester dialysis membranes and disposable electrodes.
- Evaluated membranes with 100-500 Da molecular weight cut-off (MWCO) for concentration.
- Studied parameters like draw solution, osmotic gradient, pH, and temperature.
- Tested the system with phosphate-buffered saline (PBS), urine, and saliva samples.
- Assessed electrochemical signal enhancement for pyocyanin detection.
Main Results:
- Optimized system using sucrose draw solution achieved water removal rates of 0.023 mL/min.
- Concentrated PBS up to 20-fold, urine 15-fold, and saliva 5-fold in under 3 hours.
- Demonstrated a 5-fold increase in electrochemical signal for pyocyanin detection.
- Identified pyocyanin as a biomarker for Pseudomonas aeruginosa diagnostics.
Conclusions:
- The microfluidics system effectively concentrates microliter biofluid samples using osmotic principles.
- The system enhances electrochemical signals, improving detection limits for biomarkers like pyocyanin.
- This technology offers a low-cost solution for signal amplification in point-of-care diagnostics.
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