“High-throughput aptamer screening” is a method used to rapidly identify aptamers—short single-stranded DNA or RNA molecules—that can bind specifically to a target molecule, such as a protein, small molecule, or even whole cells. Let’s break this down in detail: 1. What Are Aptamers? Aptamers are oligonucleotides (DNA or RNA) that fold into specific three-dimensional shapes allowing them to bind with high affinity and specificity to their targets. They function similarly to antibodies but are synthetic, smaller, more stable, and can be chemically modified. 2. High-Throughput Screening (HTS) in Aptamer Discovery Traditional aptamer discovery uses SELEX (Systematic Evolution of Ligands by Exponential Enrichment), which involves multiple iterative rounds of binding, separation, and amplification. High-throughput aptamer screening accelerates this process by using automation and large-scale technologies to simultaneously test thousands to millions of sequences against the target. 3. Key Techniques in High-Throughput Aptamer Screening Microarray-Based Screening Thousands of aptamer candidates are immobilized on a chip. The target (protein, small molecule, or cell) is fluorescently labeled and applied. Aptamers that bind the target emit signals detected by imaging. Next-Generation Sequencing (NGS)-Coupled SELEX After each SELEX round, sequences are analyzed via NGS. Sequence enrichment patterns reveal high-affinity aptamer candidates without the need for extensive…
The unique secondary and tertiary structures of aptamers provide the specificity to detect even small structural changes in the target molecule, including the presence or absence of methyl or hydroxyl groups or differences in enantiomeric configurations. Aptamers that bind specific targets are identified through a process known as Systematic Evolution of Ligands by Exponential enrichment (SELEX) in which binding molecules are selected from a large and diverse library of nucleic acids (either DNAs or RNAs). In this process, the nucleic acid library is incubated with the target molecule. Non-binding nucleic acids are then washed away, leaving behind only the molecules that have a capacity to bind to the target molecule. The nucleic acids that are not washed away are then used to create a new library of nucleic acids that is enriched for the subset that binds the desired target. Repeating this selection-cycle on each subsequent library with increasing stringency of binding (e.g. lower concentration of target), ensures that nucleic acids that bind to the target with both high specificity and high affinity are enriched. Aptamers are short, single-stranded oligonucleotides (DNA or RNA) that bind to specific target molecules with high affinity and specificity. They are often called "chemical antibodies."…
