Aptamers targeting different functional groups of 17β-estradiol

Area of Science:

• Biochemistry
• Molecular Biology
• Analytical Chemistry

Background:

• Aptamers are synthetic DNA or RNA molecules used as recognition elements in biosensors.
• Systematic Evolution of Ligands by Exponential Enrichment (SELEX) is an in vitro method for generating high-affinity aptamers.
• 17β-estradiol (E2) is a key steroid hormone with significant biological relevance.

Purpose of the Study:

• To select ssDNA aptamers that bind to distinct functional groups of 17β-estradiol (E2).
• To demonstrate the epitope specificity of the generated aptamers against related steroid hormones.
• To explore the potential application of these aptamers in developing a cross-reactive aptasensor for steroid hormone monitoring.

Main Methods:

• Systematic Evolution of Ligands by Exponential Enrichment (SELEX) was employed for aptamer generation.
• Positive selection steps used E2 as the target molecule.
• Counterselection steps utilized nortestosterone and dexamethasone to ensure specificity for different E2 epitopes.

Main Results:

• Two distinct sets of ssDNA aptamers were successfully selected against E2.
• One aptamer set targets the hydroxylated aromatic A ring of E2.
• Another aptamer set binds to the B, C, and D rings of E2, demonstrating epitope specificity.
• Binding responses to structurally related steroid hormones confirmed aptamer specificity.

Conclusions:

• Selected aptamers exhibit specific binding to different regions of E2.
• These aptamers hold potential for the development of a cross-reactive aptasensor.
• The proposed aptasensor could facilitate real-time, in-field monitoring of various steroid hormones.