Highly Sensitive β-Lactoglobulin Fluorescent Aptamer Biosensors Based on Tungsten Disulfide Nanosheets and DNase I-Assisted Signal Amplification

Abstract

β-lactoglobulin (β-Lg) is a protein found in milk that can cause severe allergic reactions, including rash, vomiting, and diarrhea. Thus, it is crucial to develop a sensitive β-Lg detection method to protect people who are susceptible to allergies. Here, we introduce a novel and highly sensitive fluorescent aptamer biosensor for detecting β-Lg. First, a fluorescein-based dye (FAM)-labeled β-lactoglobulin aptamer (β-Lg aptamer) is adsorbed on the surface of tungsten disulfide (WS2) nanosheets via van der Waals forces, resulting in fluorescence quenching. When β-Lg is present, the β-Lg aptamer selectively binds to β-Lg, causing a conformational change in the β-Lg aptamer and releasing it from the surface of WS2 nanosheets, which restores the fluorescence signal. Simultaneously, DNase I in the system cleaves the aptamer bound to the target, producing a short oligonucleotide fragment and releasing β-Lg. The released β-Lg then binds to another β-Lg aptamer adsorbed on WS2, initiating the next round of cleavage, resulting in significant amplification of the fluorescence signal. This method has a linear detection range of 1–100 ng mL−1, and the limit of detection is 0.344 ng mL−1. Furthermore, this approach has been successfully used for detecting β-Lg in milk samples with satisfactory results, providing new opportunities for food analysis and quality control.

A rapid and sensitive aptamer-based biosensor for beta-lactoglobulin in milk

“…The spiked milk samples were processed according to the established protocols outlined in a previous study. 34 The samples underwent a series of processes, including heating at 40 °C for 30 min, centrifugation at 8000 rpm for 20 min, cooling for 15 min, the collection of the supernatant, pH adjustment to 4.6, further centrifugation at 8000 rpm for 20 min to precipitate casein, filtration through a 0.2 μm polycarbonate membrane, pH adjustment to 7.5 with 1 M sodium hydroxide, and dilution. The β-Lg solution was then diluted to different concentrations (15, 75, and 750 ng mL −1 ) of the prepared solution for subsequent detection.…”

Recent Advances in Polymer-Based Biosensors for Food Safety Detection

“…β-lactoglobulin (β-LG) is a major milk allergen that can cause a range of allergic reactions, including skin irritation, respiratory distress, gastrointestinal issues, and even systemic allergic reactions [ 81 ]. To detect β-LG, several biosensors have been developed that employ innovative techniques to detect the allergen in real food samples [ 82 ].…”