QUANTITATIVE LATERAL FLOW IMMUNOASSAY FOR MEASURING PROGESTERONE IN BOVINE MILK

摘要

Milk progesterone has been shown to be an accurate indicator of ovulation, thereby creating the potential for improved reproductive management with the development of appropriate sensors. The objectives of this research were to develop a lateral flow immunoassay for measuring progesterone in bovine milk and to develop a sensor to quantify the assay results. Antigen-capture with antigen-competition was used for the format of the assay, with horseradish peroxidase as the enzyme label. Test strips were made using polyester-backed nitrocellulose membrane. The sensor was configured for measuring transmittance using a 645 nm light-emitting diode as the light source and a large-area photodiode as the detector. Intensity measurements were taken for 4 min at 30 s intervals and converted to optical density. The sensor was calibrated with buffer standards and progesterone-spiked milk. Tukey tests and Duncan multiple range tests showed that the system was able to detect mean differences between 5 and 10 ng/mL progesterone in buffer. For milk, the system was able to detect mean differences between 1 and 50 ng/mL progesterone based on the Tukey test, and between 5 and 50 ng/mL progesterone based on the Duncan multiple range test. A linear regression with a 95% prediction interval was calculated for concentration levels in the linear region, but the wide prediction interval made it difficult to determine the limit of detection.