Waterborne protozoan parasite detection using two-frequency impedance flow cytometry

Area of Science:

• Environmental Science
• Biotechnology
• Analytical Chemistry

Background:

• Waterborne parasitic protozoa cause significant gastrointestinal diseases in humans and animals.
• Existing water treatment methods are insufficient, necessitating continuous monitoring for early detection of parasites.

Purpose of the Study:

• To develop and validate a microfluidic system for real-time detection and identification of waterborne parasitic protozoa.
• To discriminate between Giardia and Cryptosporidium (oo)cysts at the individual level in flowing water.

Main Methods:

• A microfluidic channel with micromachined differential coplanar microelectrodes was designed.
• Two-frequency impedance flow cytometry (IFC) was employed, applying simultaneous low and high frequencies.
• Amplitude and phase variances were measured to characterize and identify parasitic (oo)cysts and non-parasitic particles.

Main Results:

• The system achieved a detection limit of <0.1% volume ratio for individual (oo)cysts.
• High discrimination between parasitic (oo)cysts and polystyrene particles was demonstrated.
• Successful detection and identification were achieved in both deionized and filtered creek water.

Conclusions:

• The proposed IFC system offers a sensitive and specific method for continuous monitoring of waterborne parasitic protozoa.
• The use of differential coplanar electrodes and dual-frequency analysis enhances detection capabilities in natural water environments.