Abstract: Objective: Based on the protective effect of aptamers on the aggregation of graphene oxide (GO) aqueous solution, we established a highly sensitive and specific aptasensor for the detection of streptomycin (STR) residues. Methods: In saturated GO aqueous solution, a STR-specific aptamer could interact with the surface of GO via hydrophobic and π-π stacking interactions between the ring structures in the nucleo-bases and the hexagonal cells of GO to promote its dispersion. When STR entered the system, the aptamer was combines with STR and separated from GO, resulting in decreased GO dispersion and consequently aggregation. After centrifugation, the ultraviolet (UV) absorbance of the supernatant was determined at 230 nm. The linear relationship between the absorbance and STR concentration was established thereby allowing quantitative detection of STR. Results: Under the optimized conditions, the UV absorbance of GO decreased with the increase in STR concentration and had a good linear relationship with the logarithm of STR concentration in the range of 0.002 4–240 ng/mL, which was fitted as follows: A = -0.105 73lgCSTR + 0.471 5 (R2 = 0.994). The detection limit was 0.001 3 ng/mL. The average recoveries for spiked honey samples from two different sources were 89.3%–108.1% and 94.7%–110%, respectively. Conclusion: The aptasensor developed in this study can be used to rapidly detect STR residues with good repeatability and stability and high sensitivity.

Key words: aptamer, sensor, streptomycin, graphene oxide, honey