Affinity immunosensor for milk progesterone: identification of critical parameters

Area of Science:

• Analytical Chemistry
• Biotechnology
• Veterinary Diagnostics

Background:

• Accurate milk progesterone measurement is crucial for dairy herd reproductive management.
• Competitive-type immunochromatographic assays offer rapid on-site testing capabilities.
• Optimizing assay parameters is essential for reliable and sensitive progesterone detection.

Purpose of the Study:

• To investigate the impact of key experimental parameters on a milk progesterone immunochromatographic assay.
• To identify optimal conditions for enhancing assay sensitivity and signal output.
• To evaluate buffer system compatibility for robust assay performance.

Main Methods:

• A competitive-type immunochromatographic assay for milk progesterone was developed.
• Colloidal gold particle size, antibody concentration in the detection zone, and buffer systems were systematically varied.
• Assay performance was evaluated based on maximal signal and sensitivity (slope of the standard curve).

Main Results:

• Increasing colloidal gold particle size led to higher maximal signal and improved assay sensitivity.
• Antibody concentration in the detection zone was critical; low concentrations severely reduced sensitivity.
• The assay demonstrated good performance across a broad pH range (4.5-8.5) with various buffer systems.

Conclusions:

• Colloidal gold particle size and antibody concentration are critical factors for optimizing milk progesterone immunochromatographic assays.
• These findings provide a basis for developing more sensitive and reliable on-farm progesterone testing methods.
• The assay's robustness across a wide pH range facilitates its application in diverse field conditions.