Aptamer Discovery Platform

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 composed of ribonucleic acid (RNA). RNA aptamers occur naturally within cells and are involved in a variety of biological processes, such as protein synthesis and gene expression regulation. They have more complex structures, such as hairpin rings, pseudoknots, etc., which contribute to their high affinity binding to target molecules.

Process of Cell-SELEX Aptamer Screening

Fig.1 Process of Cell-SELEX Aptamer Screening

Initial Library Construction

We offer multiple SELEX screening strategies depending on the target type and project requirements. Our SELEX platform supports: Protein targets (recombinant, native or purified proteins) Cell-based targets (Cell-SELEX for cancer, immune or stem cells) Small molecules and metabolites Ions and peptides Screening methods include traditional SELEX, Capture-SELEX, homogeneous solution-phase SELEX and automated SELEX. These strategies help enrich high-affinity aptamers efficiently while minimizing non-specific binding. Binding Assay and Affinity Validation After screening, aptamers undergo systematic verification.

KMD Bioscience evaluates the binding affinity (Kd), specificity, thermal stability and performance under application-relevant conditions. Validated aptamers are delivered with complete sequence information and experimental data for downstream research, sensor development or therapeutic studies.

Application of Cell-SELEX

Aptamers targeting specific molecules on the surface of tumor cells are screened by Cell-SELEX technology, which can be used for early estimate and therapeutic monitoring of tumors. For example, studies have shown that aptamers screened by Cell-SELEX technology can specifically bind Frizzled-8 protein on tumor Cell surface and can be used for fluorescence imaging differential diagnosis of tumor tissues.

Fig.2 Application of Cell-SELEX In Cancer. (Reference Source: Progress on Aptamer for Cancer Theranostics[J].)

Advantages of SELEX at KMD Bioscience

1. Proven experience with multiple completed aptamer projects
2. Versatile screening methods suitable for different target types
3. High-purity chemical synthesis and flexible modification options
4. Robust validation system with quantifiable affinity evaluation
5. Customized project design, technical communication and full documentation
6. Integrated service from design to validation, reducing development time and cost