Selection and elution of aptamers using nanoporous sol-gel arrays with integrated microheaters

Abstract

RNA and DNA aptamers that bind to target molecules with high specificity and affinity have been a focus of diagnostics and therapeutic research. These aptamers are obtained by SELEX (Systematic Evolution of Ligands by EXponential enrichment) often requiring more than 10 successive cycles of selection and amplification, where each cycle normally takes 2 days per cycle of SELEX. Here, we have demonstrated the use of sol-gel arrays of proteins in a microfluidic system for efficient selection of RNA aptamers against multiple target molecules. The microfluidic chip incorporates five sol-gel binding droplets, within which specific target proteins are imbedded. The droplets are patterned on top of individually addressable electrical microheaters used for selective elution of aptamers bound to target proteins in the sol-gel droplets. We demonstrate that specific aptamers bind their respective protein targets and can be selectively eluted by micro-heating. Finally, our microfluidic SELEX system greatly improved selection efficiency, reducing the number of selection cycles needed to produce high affinity aptamers. The process is readily scalable to larger arrays of sol-gel-embedded proteins. To our knowledge, this is the first demonstration of a chip-based selection of aptamers using microfluidics, thereby allowing development of a high throughput and efficient SELEX procedures.

Development of Single-Stranded DNA Aptamers for Specific Bisphenol A Detection

“…These features enhance stability and sensitivity of aptamer sensing. Therefore, we believe that sol-gel chips are suitable platforms for aptamer screening and detection (Park et al, 2009). …”

Nanomaterial-assisted aptamers for optical sensing

“…Up to now, approximately 250 aptamers have been sequenced. The recent progress in SELEX techniques enables rapid and efficient selections of aptamers for targets within only a few hours (Lou et al, 2009;Park et al, 2009) compared to traditional SELEX requiring several weeks to months. Nanomaterials with different optical, magnetic and electric properties provide powerful tools to design ideal signal-enhanced optical NAAs, which are summarized in Table 1.…”

Selection of aptamers in SELEX process

“…Seung-min and Jiyoung et al [46][47][48] reported a novel method to develop a microfluidic sol-gel device that could allow high-throughput aptamer selection and characterization of RNA aptamers. Their microchip utilized nanoporous sol-gel networks to immobilize the target protein and a localized aluminum heat source to selectively elute the RNA aptamers from target protein.…”