An exceptionally intense turn-on fluorescence sensor in the far-red region for common milk allergen, β-lactoglobulin

Common milk allergens, such as, beta-lactoglobulin (beta-LG), poses a major health concern for public, particularly in children. Thus, sensitive and selective methods for detection of common milk allergens are highly warranted. To the best of our knowledge, detection and quantification of ll-lactoglobulin, a common milk allergen, by fluo-rescence based technique has not been reported till date. Herein, we present the first ever fluorescence based report for the selective detection and quantification of milk allergen, beta-LG, using LDS-798 as a fluorogenic probe, which registers an exceptionally large fluorescence enhancement of -2900 fold in the far-red region upon binding with beta-LG with LOD of 6.3 (+/- 0.3) nM for beta-LG in aqueous buffer solution and 0.67 (+/- 0.04) mu M in 5% bovine milk matrix respectively. High sensitivity and selectivity, fast response, high repeatability and reproducibility, easy operation, along with emission in the technologically advantageous far-red region make the fluorometric quantification of beta-LG, using LDS-798 as a fluorogenic probe, far more advantageous than the other techniques, generally used for beta-LG quantification. Importantly, we have demonstrated the applicability of this probe for quantification of beta-LG in real milk samples which has been validated by an established method.

Automated summary

This study presents a novel fluorescence-based method for selective detection and quantification of the common milk allergen beta-LG, demonstrating high sensitivity, selectivity, fast response, and ease of operation. The method utilizes LDS-798 as a fluorogenic probe and achieves a significant fluorescence enhancement upon binding with beta-LG, making it more advantageous than other techniques commonly used for beta-LG quantification. Additionally, the applicability of the probe for quantification of beta-LG in real milk samples has been successfully validated.