Microfiltration sampling in rats and in cows: toward a portable device for continuous glucocorticoid hormone sampling

Area of Science:

• Veterinary Medicine
• Biomedical Engineering
• Endocrinology

Background:

• Traditional blood sampling for monitoring animal hormones is invasive and stressful, especially for repeated measurements.
• Existing methods limit continuous hormone level assessment in freely moving animals.

Purpose of the Study:

• To develop and evaluate a minimally invasive Microfiltration Collection Device (MCD) for continuous, pulse-free monitoring of glucocorticoid hormones in animals.
• To assess the efficacy of different hollow fiber membranes and coatings for optimal device performance.

Main Methods:

• Developed an MCD utilizing a hollow fiber membrane probe, capillary coil, and flow creator.
• Tested three biocompatible hollow fiber membranes in rats with varying placement and heparin coating.
• Optimized probe (polyethylene coated with ethylene vinyl alcohol-heparin) integrated into a device tested in cows for cortisol monitoring.

Main Results:

• The polyethylene probe with ethylene vinyl alcohol-heparin coating demonstrated superior performance.
• The MCD successfully monitored both protein-bound and free cortisol in cows over 7 hours.
• The device proved effective in freely active subjects, inducing minimal stress.

Conclusions:

• The developed MCD offers a less invasive and less stressful alternative to manual blood collection for hormone monitoring in animals.
• This technology facilitates continuous glucocorticoid monitoring in conscious, active animals, enabling remote analysis.
• The MCD is a lightweight, sterilizable, disposable device suitable for field applications and mail-based laboratory analysis.