Sample concentration and purification for point-of-care diagnostics

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Microfluidics

Background:

• Concentrating target analytes enhances biosensing sensitivity for infectious disease diagnosis.
• Evaporation-based concentration is effective but challenged by high protein and electrolyte levels in human samples like plasma.
• Protein dehydration and electrolyte imbalance can lead to sample gelling and pathogen lysis, hindering detection.

Purpose of the Study:

• To develop a microfluidic chip integrating dialysis and concentration for efficient sample preparation.
• To overcome limitations of traditional evaporation methods for complex biological samples.
• To improve the limit of detection for biosensing techniques, particularly for viral load testing.

Main Methods:

• Fabrication of a microfluidic chip combining dialysis and concentration functionalities.
• Processing of plasma or serum samples to remove proteins and adjust electrolyte concentrations.
• Demonstration of sample concentration by a factor of 10 in under 30 minutes.

Main Results:

• The microfluidic chip successfully dialyzed proteins while maintaining optimal electrolyte concentrations.
• Achieved a 10-fold concentration of plasma or serum samples within 30 minutes.
• Demonstrated proof-of-concept using a defective Human Immunodeficiency Virus (HIV) sample.

Conclusions:

• The developed microfluidic chip offers an effective solution for sample preparation in biosensing.
• This technology has the potential to significantly improve the sensitivity of molecular point-of-care viral load tests.
• Enables more accurate detection of low viral loads, crucial for managing conditions like HIV infection.