A magnetic relaxation switch sensor for determination of 17β-Estradiol in milk and eggs based on aptamer-functionalized Fe 3 O 4 @Au nanoparticles.

Background A simple and rapid detection method for 17β-Estradiol (E2 ) in complex food matrix is greatly desirable. A magnetic relaxation switch (MRS) sensor for detecting E2 based on the aptamer-functionalized Fe3 O4 @Au was designed in this study. Fe3 O4 @Au NPs played as a 'switch' between dispersed and aggregated states, while aptamer served as the recognition unit. Results According to the sensing effect of monocomponent relaxation time (T2W ) for E2 , the volume ratio of aptamers to Fe3 O4 @Au, the NaCl concentration, the concentration of Fe3 O4 @Au@Apt, and reaction time were optimized to be 4:1, 0.03 M, 4 μM and 15 min, respectively. For the analysis of food sample, the E2 was quantified over a concentration range of 1 nM to 100 nM with a detection limit of 7.6 nM for milk samples, while a linearity range of 20-100 nM and a detection limit of 8.57 nM for egg samples. Conclusion These results exhibited that the MRS sensor could be a promising platform for the rapid detecting of E2 in food sample. This article is protected by copyright. All rights reserved.