Self-Responsive Fluorescence Aptasensor for Lactoferrin Determination in Dairy Products

• Published in: Molecules (Basel, Switzerland) Switzerland), 2024-06, Vol.29 (13), p.3013
• Main Authors: Liu, Hao, Gao, Xibao, Qin, Hongwei, Yan, Mengmeng, Zhu, Chao, Li, Linsen, Qu, Feng
• Format: Article
• Language: English
• Subjects: Amino acids; Antibodies; aptamer; Aptamers, Nucleotide - chemistry; Baby foods; Biosensing Techniques - methods; Biosensors; Breastfeeding & lactation; Chromatography; Dairy products; Dairy Products - analysis; Enzymes; Fluorescence; fluorescence aptasensor; Fluorescence Resonance Energy Transfer - methods; Food Analysis - methods; Immunoassay; Lactoferrin - analysis; Lactoferrin - chemistry; lactoferrin detection; Limit of Detection; Medical diagnosis; Proteins; self-responsive; Spectrometry, Fluorescence - methods
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules29133013

In this study, a self-responsive fluorescence aptasensor was established for the determination of lactoferrin (Lf) in dairy products. Herein, the aptamer itself functions as both a recognition element that specifically binds to Lf and a fluorescent signal reporter in conjunction with fluorescent moiety. In the presence of Lf, the aptamer preferentially binds to Lf due to its specific and high-affinity recognition by folding into a self-assembled and three-dimensional spatial structure. Meanwhile, its reduced spatial distance in the aptamer-Lf complex induces a FRET phenomenon based on the quenching of 6-FAM by amino acids in the Lf protein, resulting in a turn-off of the fluorescence of the system. As a result, the Lf concentration can be determined straightforwardly corresponding to the change in the self-responsive fluorescence signal. Under the optimized conditions, good linearities (R > 0.99) were achieved in an Lf concentration range of 2~10 μg/mL for both standard solutions and the spiked matrix, as well as with the desirable detection limits of 0.68 μg/mL and 0.46 μg/mL, respectively. Moreover, the fluorescence aptasensor exhibited reliable recoveries (89.5-104.3%) in terms of detecting Lf in three commercial samples, which is comparable to the accuracy of the HPCE method. The fluorescence aptasensor offers a user-friendly, cost-efficient, and promising sensor platform for point-of-need detection.