Categorization & Core Principle All these techniques share the common goal of SELEX (Systematic Evolution of Ligands by EXponential enrichment): isolating high-affinity aptamers from a vast random-sequence library (10^14 - 10^15 sequences) through iterative cycles of Binding → Separation → Amplification → Purification. Your listed techniques primarily differ in the separation method used to partition target-binding sequences from non-binders. Detailed Analysis & Context A. Classical SELEX (Solution-based) What it is: The foundational, versatile protocol. The target is often immobilized to facilitate separation. Separation Method: Filtration, affinity columns, or magnetic beads (if target is tagged/bound to a bead). Note: "SELEX technology" is the umbrella term. Techniques B, C, D, and E are all variants of SELEX that use different separation principles. B. Solid-Phase SELEX (A specific implementation of classical SELEX) Clarification: This is the most common practical implementation for small molecules. The "solid phase carrier" is typically streptavidin-coated beads if the target is biotinylated, or an activated resin if the target is chemically immobilized. Key Advantage: Excellent for counter-selection (to remove sequences that bind to the solid support or similar non-target molecules). C. Centrifugal Precipitation / Particle-Based SELEX Best For: As you noted, it's ideal for cells, bacteria, or large vesicles. For true small molecules, this method is less common unless the small molecule is…
Core Challenge with Small Molecules Small molecules (e.g., drugs, toxins, metabolites, <1000 Da) lack the large, multi-epitope surfaces of proteins. This makes traditional selection methods difficult because: Immobilization: Hard to attach to a solid phase without masking the target area. Limited Binding Interfaces: Offer fewer points for oligonucleotide interaction. Low Signal-to-Noise: Distinguishing specific binders from non-specific binders is tougher. Key Aptamer Screening Techniques Used for Small Molecules KMD Bioscience likely employs a combination of these advanced SELEX (Systematic Evolution of Ligands by EXponential Enrichment) variants: 1. Capture-SELEX (The most common for small molecules) Principle: Instead of immobilizing the small molecule, a DNA library with a fixed primer sequence is immobilized on beads. The small molecule is free in solution. Process: The small molecule is introduced. Sequences that bind to it undergo a conformational change, freeing them from the bead into the solution. These eluted sequences are then amplified. Advantage: The target remains in its native, unmodified state, preserving its structure and function. Ideal for targets that are difficult to tag or immobilize. 2. Graphene Oxide-SELEX (GO-SELEX) Principle: Utilizes graphene oxide's ability to adsorb single-stranded DNA (ssDNA) non-specifically via π-π stacking. Process: The ssDNA library is incubated with GO. Unbound sequences are discarded. The small molecule target is then added. Aptamers…
Aptamer Selection Small molecule aptamer screening techniques generally include the following steps: A. Initial library design: Build a DNA, RNA or peptide library containing a large number of random sequences that have the potential to bind to small target molecules. B. Screening process: The main steps include target binding to the library, isolation and purification of the binding target molecule aptamer PCR amplification, iterative screening and so on. After each round of screening, the screening results can be verified and analyzed through technologies such as sequencing. C. Optimization and validation: The selected aptamers were optimized to improve their affinity, specificity and stability. Subsequently, a series of experiments were carried out to verify its binding ability and application effect. KMD Bioscience Aptamer Screening Service: A Comprehensive Workflow Your description accurately captures the three universal pillars of in vitro selection (SELEX). KMD Bioscience would operationalize these into a robust, client-tailored service. A. Initial Library Design & Preparation Library Diversity: Construction of high-complexity synthetic libraries (typically 10^14 - 10^15 unique sequences) containing a central random region (e.g., 30-60 nucleotides) flanked by constant primer regions. Format Flexibility: Offering DNA, RNA, or modified nucleotide (e.g., 2'-F, 2'-O-Me) libraries to balance stability, cost, and affinity requirements. Target Immobilization: A critical initial step where the small molecule target is…
KMD Bioscience Aptamer Screening Service: Aptamer Types Aptamers are oligonucleotide or peptide sequences obtained through in vitro selection techniques (such as SELEX) that exhibit high specificity and affinity for target molecules. Based on molecular composition, aptamers are primarily categorized into two main types: Nucleic Acid Aptamers and Peptide Aptamers. Both types demonstrate strong target recognition and binding capabilities. Main Types and Characteristics Type Composition Structure and Properties DNA Aptamers Composed of short single-stranded DNA molecules. Can fold into specific three-dimensional structures to recognize and bind targets. Generally more stable than RNA aptamers, and easier to synthesize and modify. RNA Aptamers Composed of short single-stranded RNA molecules. Can also fold into complex three-dimensional structures for high-specificity target binding. Often exhibit greater structural diversity, but natural RNA is susceptible to degradation and often requires chemical modifications for enhanced stability. Peptide Aptamers Consist of short peptide sequences made of amino acids. Typically presented on a stable protein scaffold (e.g., thioredoxin). This design enhances binding affinity and stability towards the target while maintaining peptide flexibility and specificity. Service Value KMD Bioscience's aptamer screening service covers all the above types. Depending on your target characteristics and research objectives (e.g., diagnostics, therapeutics, assay development), we provide end-to-end solutions—from library design and in…
Small molecule aptamers refer to DNA or RNA single strand oligonucleotide sequences with high affinity and high specificity to specific small molecule targets that are screened from random sequence libraries by SELEX technology, and can also be peptides. After years of development, KMD Bioscience has great technical advantages in aptamer selection. With the continuous development and improvement of aptamer technology, the application prospect of small molecule aptamer in the field of biomedicine and medicine research and development will be broader. Small molecule aptamers have important application value in medicine research and development. By obtaining highly specific aptamers for specific small molecules, it can provide important basis for medicine design and optimization, and accelerate the development process of new medicines. In the targeted therapy of diseases such as cancer, aptamers can bind specifically to specific antigens or receptors on the surface of tumor cells, thus achieving precise treatment. KMD Bioscience can provide customized peptide aptamer screening services according to the different experimental and application needs of customers. Aptamer Type According to the type of molecule, aptamers can be divided into two main categories: nucleic acid aptamers and peptide aptamers. Nucleic acid aptamers can be divided into DNA aptamers and RNA aptamers. Both nucleic acid aptamers and peptide aptamers…
Kmdbioscience Aptamer Screening Service We offer comprehensive in vitro aptamer screening services, enabling rapid and accurate identification of aptamers with high affinity and specificity to help clients reduce experimental costs. Our one-stop aptamer screening platform utilizes the natural evolution of ligand systems through the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) method in a flexible and efficient manner. By partnering with us, you will achieve optimal results tailored to your research and development needs.
Aptamer Screening Service: Key Features Broad Target Compatibility: Our screening services are effective for both purified proteins and small chemical molecules. Target Sourcing Flexibility: We can either provide the target or procure it commercially, eliminating the need for clients to supply physical samples. High-Precision Affinity Measurement: The binding affinity (Kd) of selected aptamers is accurately determined using Capillary Electrophoresis (CE). Multiple Candidate Delivery: Depending on screening outcomes, we typically provide several aptamer sequences for further evaluation. Transparent Process: A detailed selection protocol is included, offering full insight into how the aptamers are developed. Efficient Timeline: The standard project duration is approximately three months. Note: Our current screening success rate stands at approximately 80%. Please be aware that developing aptamers for small-sized proteins or small chemical molecules remains particularly challenging. We are continuously refining our methods to enhance screening performance and success rates.
Custom Aptamer Discovery Service: Our Tailored Development Process Curious about how we identify precision-targeting aptamers? Our step-by-step workflow is designed to isolate high-affinity molecular binders for your specific target. Our Proven Development Pathway: 1. Design & Synthesis of Custom ssDNA Library We construct a diverse single-stranded DNA library with randomized sequences, tailored to your target's properties for optimal screening potential. 2. Target-Specific Binding Selection Your target molecule (protein, small molecule, or cell) is incubated with our curated DNA library under optimized conditions to capture specific binders. 3. Rigorous SELEX Enrichment Cycles Through multiple iterative rounds of: Stringent Washing – Removal of non-specific binders Selective Elution – Recovery of target-bound sequences Controlled PCR Amplification – Enrichment of high-affinity candidates 4. Next-Generation Sequencing & Bioinformatics Analysis Deep sequencing of enriched pools followed by advanced computational analysis to identify conserved binding motifs and candidate families. 5. Comprehensive Affinity Validation Each candidate undergoes thorough characterization including: Kd Determination – Precise binding affinity measurement Specificity Profiling – Cross-reactivity assessment Functional Validation – Performance evaluation in your intended application format Deliverables: Fully characterized aptamer sequences with binding parameters Specificity validation data Optimization for your required buffer conditions Technical support for implementation Our Advantage: Proprietary screening methodologies, stringent counter-selection protocols, and integrated computational design…
Nucleic acid aptamers are short, single-stranded oligonucleotides (ssDNA or ssRNA) capable of binding with high affinity and specificity to diverse targets, ranging from small molecules and proteins to entire cells. Due to their versatility and stability, aptamers have become invaluable tools in both basic research and clinical applications. The standard method for aptamer identification is Systematic Evolution of Ligands by Exponential Enrichment (SELEX), an iterative process involving repeated cycles of incubation, separation, elution, amplification, and single-strand purification, followed by sequencing. At KMDbioscience, we have established a proprietary and highly optimized platform for efficient and reliable aptamer screening. Our services cover aptamer development against both purified protein targets and small chemical molecules. Through our refined selection process, we consistently generate DNA aptamers with dissociation constants (Kd) in the range of 0.1–10 nM. Typically, multiple unique aptamer sequences can be identified through successive selection rounds. Depending on client needs, we can provide the full panel of candidate aptamers obtained from the screening campaign. Choose KMDbioscience as your partner to accelerate and enhance your aptamer-based projects. Let us help you advance your research and development goals with precision and expertise. Aptamer Screening Service | Aptamer Development
Custom-Tailored Aptamers with Exceptional Affinity and Specificity for Your Target Molecules Aptamers are powerful tools in biotechnology and therapeutic development, offering molecular recognition properties that rival traditional antibodies. In addition to their high targeting precision, custom aptamers provide distinct advantages: they are developed entirely in vitro, can be rapidly produced through chemical synthesis, exhibit excellent stability in storage, and show minimal immunogenicity in therapeutic contexts. KMDbioscience delivers a dedicated service to generate high-quality aptamers against your chosen targets, achieving reliable results even with complex or challenging molecules. Our aptamers are available with a range of fluorescent labeling options to support convenient detection and visualization in your applications. Our custom aptamer development utilizes a proprietary SELEX technology, enabling the rapid generation of aptamers with high binding affinity for your target molecules. Our custom aptamer services include: Aptamer Discovery Advanced SELEX using modified nucleotides Traditional SELEX using natural nucleotides Competitive and/or negative selection strategies Maturation SELEX (second-round selection using a pre-screened focused library) Aptamer Modification End-Group Modification (5’ and/or 3’): Amine, Thiol, Biotin, various fluorescent dyes, PC Biotin, PC Amine, idT, Cholesterol, etc., with or without linkers (dT, dA, HEG, PEG, etc.) Internal Modification: 2’-OMe, internal amine, internal biotin, etc. Conjugation: Pegylation (linear, branched, lysine-branched),…
