What are Aptamers? Aptamers are single-stranded DNA or RNA molecules obtained through in vitro selection techniques (such as SELEX) from synthetic, randomized nucleic acid libraries. They can bind to target molecules (such as proteins, small molecules, cells, etc.) with high affinity and specificity through unique three-dimensional structures, earning them the titles "chemical antibodies" or "nucleic acid antibodies." Key Characteristics Chemical Nature Mostly single-stranded DNA or RNA, producible via chemical synthesis, offering good stability and ease of modification or labeling. Binding Mechanism Form hydrogen bonds, electrostatic interactions, etc., through spatial conformations (e.g., hairpins, pockets, bulges) to recognize targets with atomic-level precision. High Affinity & Specificity Capable of distinguishing structurally similar molecules (e.g., caffeine vs. theophylline), with dissociation constants (Kd) reaching nanomolar (nM) or even picomolar (pM) levels. Strong Stability Resistant to high temperatures, reversible denaturation, and less susceptible to damage in acidic/basic environments (especially DNA aptamers), making them suitable for complex applications. Advantages Compared to Antibodies Feature Aptamers Antibodies (Traditional Protein Antibodies) Production Time In vitro selection (weeks), chemical synthesis, high batch consistency Animal immunization or cell culture (months), significant batch variability Stability Heat-resistant, easy storage, transportable at room temperature Prone to denaturation, requires cold storage Modification Flexibility Easy labeling with fluorescent dyes, isotopes, etc. Modifications may affect structure Immunogenicity…
Aptamers are nucleic acid sequences that specifically bind with target molecules and are vital to applications such as biosensing, drug development, disease diagnostics, etc. The traditional selection procedure of aptamers is based on the Systematic Evolution of Ligands by an Exponential Enrichment (SELEX) process, which relies on repeating cycles of screening and amplification. With the rapid development of aptamer applications, RNA and XNA aptamers draw more attention than before. But their selection is troublesome due to the necessary reverse transcription and transcription process (RNA) or low efficiency and accuracy of enzymes for amplification (XNA). In light of this, we review the recent advances in aptamer selection methods and give an outlook on future development in a non-SELEX approach, which simplifies the procedure and reduces the experimental costs. We first provide an overview of the traditional SELEX methods mostly designed for screening DNA aptamers to introduce the common tools and methods. Then a section on the current screening methods for RNA and XNA is prepared to demonstrate the efforts put into screening these aptamers and the current difficulties. We further predict that the future trend of aptamer selection lies in non-SELEX methods that do not require nucleic acid amplification. We divide…
KMD Bioscience offers comprehensive aptamer discovery services that cover the full workflow—from nucleic acid aptamer design and synthesis, to multi-target SELEX screening, to final affinity and specificity validation. With advanced laboratory platforms and experienced scientists, we provide reliable and efficient one-stop aptamer solutions for diagnostics, therapeutics, biosensors and research applications. Nucleic Acid Aptamer Introduction Aptamers are single-stranded nucleic acid molecules (DNA or RNA) that fold into stable three-dimensional structures capable of binding specific targets with high affinity. Compared with antibodies, aptamers offer several advantages, including small molecular size, low immunogenicity, chemical synthesis, batch consistency and flexible modification. They can bind diverse targets such as proteins, peptides, cells, small molecules and ions, making them valuable tools in biotechnology and analytical applications. DNA Aptamer: DNA aptamers are aptamers composed of deoxyribonucleic acid (DNA). They usually have a double helix structure and are composed of four bases (adenine A, thymine T, guanine G, cytosine C) connected by phosphodiester bonds. They are single-stranded oligonucleotide sequences, typically with 56-120 bases, that bind the target sequence efficiently by recognizing specific spatial structures. DNA aptamers are widely used in biological analysis, biomedicine, and other fields because of their stability and easy chemical modification. RNA Aptamers: RNA aptamers are aptamers…
1. What is metal ion aptamer screening? A: The aptamer is a small nucleic acid folded in a three-dimensional conformation to make the aptamer a specific binding target. The target has a variety of species, either proteins small molecules, or metal ions. In contrast to antibodies, aptamers enable in vitro selection with low immunogenicity. Among them, heavy metal, as the most toxic metal pollutant, can pollute the natural environment, and detecting heavy metal pollution has become an important task. At the same time, heavy metals are also classified as trace elements because of their low content. Therefore, developing an accurate and sensitive heavy metal detection method is very important to ensure human and environmental safety. Aptamers as biological probes show high binding affinity that can be directly converted to high detection sensitivity. On the other hand, high selectivity and stability enable it to detect various targets, especially metal ions. Since identifying aptamers for metal ions, aptamer-based sensors and detection methods have become possible and provide new methods for detecting metal ions, including electrochemical, colorimetric, and fluorometry. KMD Bioscience has been studying in the field of nucleic aptamers for a long time, which can provide customers with metal ion aptamers with excellent performance to help customers better…
Due to its high specificity, strong affinity, excellent stability, and ease of preparation and labeling, the screening techniques for aptamers in fields such as cells, fungi, proteins, and small molecules have become increasingly sophisticated. Due to the small molecular weight and single binding site of metal ions, screening methods need to be specially designed. Current research mainly focuses on heavy metal ion aptamers, such as Pb2+, Cd2+, and Hg+. KMD Bioscience provides metal ion nucleic acid aptamer screening services through affinity chromatography SELEX and graphene oxide SELEX, based on the selenium library screening technology. When conducting metal ion adaptation screening, there are certain requirements for the sample, and the metal ion sample should have high purity to reduce the interference of impurities in the screening process. The concentration of metal ions should be moderate, neither too high nor too low, to ensure effective binding during the screening process. Metal ion samples should be kept stable to avoid chemical changes or degradation during the screening process. Relatively speaking, selex library should have sufficient sequence diversity to cover possible adapter sequences. The length of oligonucleotide sequences should be moderate to form stable structures and effectively bind with metal ions. The metal ion sample and…
Metal Ion Nucleic Acid Aptamer Screening Service Workflow Step Service Content Timeline Step 1: Screening of nucleic acid aptamers (1) Customer provides screening targets. (2) The adapter library is fixed on an affinity chromatography column and incubated with metal ions injected into the column. (3) Adaptation library screening and enrichment: PCR amplification enrichment+transcription+gel running recovery, usually 6-10 rounds. (4) Screening products for NGS sequencing. (5) Delivery: 5-15 adapter sequences, experimental report, raw data (including NGS sequencing raw data and gel electrophoresis) 10-15 weeks Step2：Synthesis of aptamers and determination of affinity (optional) (1) Synthesize aptamers based on sequences. (2) Affinity determination of adapter and target protein, KD determination by BLI or SPR. (3) Delivery: Experimental report, raw data
KMD Bioscience, with years of research experience in antibody discovery, focuses on providing customers with efficient, highly specific, and affinity nucleic acid aptamer in vitro screening services. Based on customers' specific screening targets, we tailor aptamer selex screening solutions and quickly and accurately screen aptamers for the target. KMD Bioscience can provide aptamer selex screening services based on multiple sample types (including proteins, peptides, amino acids, small molecule substances, cells and bacteria, metal ions, etc.), and the services provided to customers cover the upstream and downstream of aptamer selex screening, from gene analysis and synthesis, nucleic acid aptamer sequence design, aptamer in vitro screening, aptamer synthesis, to affinity determination. KMD Bioscience can arrange experiments at every stage according to customer needs. For some metal ions with simple structures and single binding sites, KMD Bioscience uses affinity chromatography SELEX and graphene oxide SELEX screening techniques, carefully planned by a team of scientists to meet the diverse needs of customers. The nucleic acid aptamer services provided by KMD Bioscience for various types of samples are based on the SELEX screening technology of the SELEX library to screen and obtain corresponding DNA or RNA sequences. Multiple screening methods (including but not limited to cell-SELEX, magnetic bead SELEX, affinity chromatography SELEX, capture SELEX,…
1. What is the cell aptamer screening service, and what are the advantages of cell aptamers? A: Our common aptamers include RNA aptamers and DNA aptamers, which targets have high affinity and specificity and are capable of high binding to the target. These aptamers have multiple functions in disease treatment and scientific research. First, it acts as a cell agonist to activate cell receptors and promote the cell to exert its effects. Secondly, it has the effect of antagonist to block the mutual binding and interaction between various structures. Furthermore, the aptamer can bind to the target so that the drug can be accurately transmitted to the therapeutic target. During the cell-SELEX screening, intact live cells were screened as a target, while the associated cell lines were used as negative controls for negative screening to exclude non-specific binding. The Cell-SELEX technology targets multiple cellular targets to generate nucleic acid aptamers, thus providing an advantage in identifying cells as molecules. In disease diagnosis, we can use aptamers for labeling, or use aptamers as a fixative to depurify the cells. These properties of aptamers provide new ideas for novel drug development. One of the highlights of the Cell-SELEX technology is the ability to retain the original conformation of the cellular receptor, which is different from screening…
Steps Service Content Timeline Step 1: Screening of nucleic acid aptamers (1) Cells were provided by the customer. (2) Adaptation library screening and enrichment: PCR amplification enrichment+transcription+gel running recovery, usually 6-10 rounds. (3) Screening products for NGS sequencing. (4) Delivery: 5-15 adapter sequences, experimental report, raw data (including NGS sequencing raw data and gel electrophoresis) 10-15 weeks Step2：Aptamer assay and FACS(optional) (1) Synthesize aptamers based on sequences. (2) Affinity determination of adapter and FACS. (3) Delivery: Experimental report, raw data 4-5 weeks