Core Components of a Small Molecule Target Service A comprehensive service follows the early drug discovery workflow: 1. Target Identification & Prioritization Bioinformatics & Omics Analysis: Mining genomic, proteomic, and clinical data to find proteins or pathways dysregulated in a disease. Genetic Screens: Using CRISPR-Cas9 or RNAi to knock out/knock down genes and identify which are essential for disease cell survival. Literature & Database Mining: Systematic review of existing scientific and patent data to propose novel or repurposable targets. 2. Target Validation In Vitro Models: Confirming the target's role in disease using engineered cell lines (overexpression, knockout) and relevant disease models (e.g., cancer cell lines, neuronal cultures). In Vivo Models: Using animal models (e.g., zebrafish, mice) to see if modulating the target (genetically or with a tool compound) has the desired therapeutic effect and is safe. Biochemical Validation: Demonstrating the target protein is expressed, has the expected activity, and is "druggable" (has a pocket where a small molecule can bind). 3. Assay Development & Screening This is a critical service. Providers develop robust tests ("assays") to measure target activity. Types of Assays: Biochemical Assays: Test compound binding/interaction with the purified target protein (e.g., enzymatic activity, protein-protein interaction). Cell-Based Assays: Test compound function in a living cell (e.g., reporter…
What is Live Cell SELEX? Traditional SELEX uses purified target proteins. Live Cell SELEX uses intact, living cells in their native state. This is crucial because: It selects for aptamers that bind to targets in their natural conformation and post-translational modifications (e.g., glycosylation). It inherently selects for cell-specificity (e.g., cancer cell vs. healthy cell) without needing to know the exact molecular target upfront. It can discover aptamers against unknown or membrane-bound targets that are difficult to purify. Core Workflow of a Typical Service A full-service provider will manage the entire pipeline: 1. Project Design & Consultation Target Cell Line Definition: Defining the "positive" cell line (e.g., patient-derived cancer cells, activated immune cells). Counter-Selection Strategy: Choosing the "negative" cell line(s) (e.g., healthy counterpart, isogenic control) to eliminate non-specific binders. Library Design: Recommending or customizing the starting random oligonucleotide library (length, modifications like 2'-F pyrimidines for RNA aptamers for stability). 2. The Selection Phase (The Iterative SELEX Cycles) Incubation: The random library is incubated with the counter-selection cells. Unbound/non-specific sequences are collected. Positive Selection: The pre-cleared library is incubated with the target cells. Cells are washed stringently. Recovery: Cell-bound aptamers are recovered (e.g., by cell lysis, heat elution, or protease treatment). Amplification: Recovered sequences are amplified by PCR (for DNA) or RT-PCR (for…
Aptamers are short, single-stranded DNA or RNA sequences that fold into 3D shapes capable of binding specific targets—proteins, small molecules, ions, cells, or even complex mixtures—with high affinity and selectivity. Because they are chemically synthesized, readily modified, and often less immunogenic than protein binders, aptamers have matured into a versatile “molecular toolkit” used across diagnostics, biosensing, therapeutics, imaging, and bioprocessing. This article explains APTAMER APPLICATIONS from fundamentals to advanced use-cases, with an emphasis on how teams translate an aptamer sequence into a functioning assay, sensor, drug carrier, or imaging probe. 1) How Aptamers Are Created (Why Selection Method Shapes Applications) Most aptamers are discovered through SELEX (Systematic Evolution of Ligands by EXponential enrichment): iterative rounds of binding, separation, and amplification that enrich sequences best suited to a chosen target and conditions. Modern SELEX variants—such as cell-SELEX, microfluidic SELEX, and capillary electrophoresis SELEX—aim to shorten selection time, improve specificity, and better match real-world sample environments. The practical result is that application performance often depends as much on selection constraints (buffer, temperature, counter-selection targets, matrix effects) as on the final nucleotide sequence. Key takeaway: If the intended application involves serum, saliva, food extracts, or environmental water, designing SELEX conditions to…
