One round-SELEX

May 8, 2024 • Bo Fu

Introduction

The concept of one round-SELEX emerged from the need to expedite the aptamer selection process while maintaining high specificity and affinity. Advances in high-throughput sequencing and bioinformatics have played a crucial role in enabling the development of one round-SELEX. Early studies focused on demonstrating that high-affinity aptamers could indeed be isolated in a single round of selection using optimized conditions and advanced analytical techniques.

One round-SELEX is an evolution of the traditional SELEX methodology, designed to address some of the limitations and inefficiencies associated with multiple rounds of selection. Traditional SELEX typically involves multiple cycles of binding, separation, and amplification to enrich high-affinity nucleic acid ligands (aptamers) from a large pool of random sequences. However, this process is time-consuming and labor-intensive. One round-SELEX was developed to streamline the selection process by reducing the number of rounds required to identify high-affinity aptamers, thereby saving time and resources.

One round-SELEX is designed to be compatible with high-throughput screening techniques, allowing for the rapid identification of aptamers. The defining character of one round-SELEX is the ability to select high-affinity aptamers in a single round of selection, making the process faster and more efficient. This method can be applied to a wide range of targets, from small molecules to proteins and even cells.

Ensuring that the selection process remains both high-throughput and accurate, without the iterative enrichment steps, posed significant technical challenges. Optimization of Selection Conditions: One of the main challenges in developing one round-SELEX was optimizing the selection conditions to ensure that high-affinity aptamers could be isolated in a single round. Balancing Specificity and Efficiency: Another difficulty was balancing the need for specificity with the efficiency of the selection process, as fewer rounds could potentially lead to higher levels of non-specific binding.

One round-SELEX represents a significant advancement in the field of aptamer selection, offering a more efficient and faster method for identifying high-affinity nucleic acid ligands, which can have a wide range of applications in diagnostics, therapeutics, and biotechnology. One round-SELEX significantly reduces the time and labor required to identify high-affinity aptamers, making the process more efficient. The method can be applied to a wide range of targets, including those that are difficult to work with using traditional SELEX methods. By streamlining the selection process, one round-SELEX facilitates the rapid development of aptamers for diagnostic, therapeutic, and research applications. Faster identification of aptamers can accelerate the development of novel therapeutics, particularly in situations where time is critical, such as in response to emerging infectious diseases.

Process

One round-SELEX usually consists of the following steps: (1) Library Preparation: A diverse library of nucleic acid sequences (RNA or DNA) is generated. (2) Target Interaction: The library is exposed to the target molecule under optimized conditions designed to maximize specific binding in a single round. (3) Separation of Bound and Unbound Sequences: After incubation, the bound sequences are separated from the unbound sequences using techniques such as affinity chromatography or magnetic separation. (4) Recovery of Bound Sequences: The bound sequences are recovered and amplified using PCR (for DNA libraries) or reverse transcription followed by PCR (for RNA libraries). (5) High-throughput Analysis: The enriched sequences are analyzed using high-throughput sequencing and bioinformatics tools to identify high-affinity aptamers.