An ultrasensitive electrochemical sensor for 17β-estradiol using split aptamers.

Herein, a simple electrochemical sensor is proposed for 17β-estradiol (E2) determination. In this sensing platform, split DNA aptamers for E2 were applied as recognizing agents. In the presence of E2, split aptamers are bound to E2 and establish split1-E2-split2 complex as a bridge on the surface of electrode. This physical bar leads to ultrasensitive detection of E2. This aptasensor is capable of recognizing E2 within 30 min without complicated procedures and expensive equipment. This sensing approach indicated a wide linear range with detection limits of 0.5 pM and 0.7 pM for E2 in tap water and milk samples, respectively. Simplicity and high specificity of the proposed electrochemical aptasensor make it an ideal sensing platform for ultra-low detection of other targets in complicated samples by replacement of split DNA aptamers.