Design and Validation of a Short Novel Estradiol Aptamer and Exploration of Its Application in Sensor Technology

Abstract

The specific and sensitive detection of 17β-estradiol (E2) is critical for diagnosing and treating numerous diseases, and aptamers have emerged as promising recognition probes for developing detection platforms. However, traditional long-sequence E2 aptamers have demonstrated limited clinical performance due to redundant structures that can affect their stability and recognition ability. There is thus an urgent need to further optimize the structure of the aptamer to build an effective detection platform for E2. In this work, we have designed a novel short aptamer that retains the key binding structure of traditional aptamers to E2 while eliminating the redundant structures. The proposed aptamer was evaluated for its binding properties using microscale thermophoresis, a gold nanoparticle-based colorimetric method, and electrochemical assays. Our results demonstrate that the proposed aptamer has excellent specific recognition ability for E2 and a high affinity with a dissociation constant of 92 nM. Moreover, the aptamer shows great potential as a recognition probe for constructing a highly specific and sensitive clinical estradiol detection platform. The aptamer-based electrochemical sensor enabled the detection of E2 with a linear range between 5 pg mL–1 and 10 ng mL–1 (R2 = 0.973), and the detection capability of a definite low concentration level was 5 pg mL–1 (S/N = 3). Overall, this novel aptamer holds great promise as a valuable tool for future studies on the role of E2 in various physiological and pathological processes and for developing sensitive and specific diagnostic assays for E2 detection in clinical applications.

Ultrahigh-Sensitivity Detection of 17β-Estradiol

“…Recently, the human-urine-based detection of E2 for its early diagnosis is gaining more popularity due to its patient-friendly and comfortable assay in comparison with serum-based assays [17][18][19][20][21], despite the fact that the E2 concentration present in human urine is much smaller than that in human serum [22]. As solutions to the aforementioned challenges associated with the limited sensitivity available from existing sensor strategies, attempts have been made with various detection mechanisms, such as plasmonic-nanoparticle-based sensors [23][24][25][26][27], fluorescence sensors [28][29][30][31][32], Raman-based sensors [33][34][35][36][37][38], electrochemical sensors [39][40][41][42][43][44][45][46][47][48][49], enzyme immunosensors [50,51], and others [52][53][54][55][56][57][58][59]. To achieve a limit of detection (LOD) of E2 comparable or lower than 1 pg/mL, most of the ultrahigh-sensitivity E2 sensors have employed signal amplification mechanisms t...…”