Nanoscale Affinity Double Layer Overcomes the Poor Antimatrix Interference Capability of Aptamers

Area of Science:

• Biotechnology
• Analytical Chemistry
• Nanotechnology

Background:

• Aptamers offer high specificity but suffer from poor antimatrix interference, limiting their use in real-world sample analysis.
• Existing detection methods often struggle with sensitivity and specificity in complex biological, food, or environmental matrices.

Purpose of the Study:

• To develop a multifunctional interface, the nanoscale affinity double layer (NADL), to overcome the limitations of aptamer-based detection.
• To achieve simultaneous in situ target enrichment, purification, and detection for enhanced analytical performance.

Main Methods:

• The NADL was constructed with an upper aptamer layer for purification/sensing and a lower nanoscale solid-phase microextraction (SPME) layer for enrichment.
• Targets were sequentially extracted by the aptamer and SPME layers for million-fold enrichment and purification.
• A fiber-optic evanescent wave sensor was utilized to demonstrate the NADL's capabilities.

Main Results:

• The NADL enabled ultrasensitive detection with unprecedented limits ranging from 0.14 fM (human serum albumin) to 800 fM (kanamycin A).
• Detection limits showed significant improvements (2500 to 3 × 10^8-fold) compared to sensors without the NADL.
• High target specificity (>1000) and tunable dynamic ranges were achieved, allowing direct detection in diluted real samples.

Conclusions:

• The NADL effectively addresses antimatrix interference, paving the way for highly sensitive and specific aptamer-based detection in complex samples.
• This technology significantly advances the application of aptamers in environmental monitoring, food safety, and clinical diagnostics.
• The NADL platform offers a versatile approach for developing next-generation biosensors with improved performance characteristics.