Whole Cell-based SELEX Services for Aptamer Development

Cell-based SELEX method is developed to screen novel aptamers against the molecules on the surface of cells without the requirement for prior knowledge of the molecular targets. Target purification is also not necessary before the selection in cell-based SELEX. Based on years of exploration, Creative Biolabs has built an advanced cell-based SELEX platform, we offer one-stop aptamer development services for customers all over the world.

Introduction of Cell-based SELEX

Cell-based SELEX method is developed to screen aptamers that bind to specific target cells. Compared to protein-based-SELEX, cell-based-SELEX does not require any prior knowledge of the protein conformation and purification of target proteins. It is employed to select aptamers using whole living cells as targets, which is crucial for discovering functional aptamers. A study showed the screened RNA aptamers using the in vitro purified histidine-tagged EGFRvIII ectodomain as targets did not bind to the full-length EGFRvIII protein expressed on the surface of eukaryotic cells. This suggests the aptamers selected by protein-based-SELEX method might not recognize the natural structure of some proteins. Therefore, the cell-based-SELEX represents a supplement to protein-based-SELEX, providing a powerful platform to discover novel aptamers against target proteins in their native conformation.

Basic Procedure of Cell-based SELEX

The main steps of cell-SELEX are similar to traditional SELEX. It includes single-stranded (ss) DNA/RNA library preparation, target incubation, binding sequence elution and amplification. After about 20 rounds of selection, the target binding aptamers are obtained. In order to optimize the specificity of the selected aptamers, a negative selection step is added prior to or immediately following target incubation to eliminate the sequences that bind target-like cells.

Schematic representation of aptamer selection using the cell-SELEX.

Fig.1 Schematic representation of aptamer selection using the cell-SELEX. (Chen, 2016)

Services

Creative Biolabs is a world-leading service provider in the field of aptamer development. Equipped with rich expertise and a first-in-class technical platform, we are very honored to offer reliable aptamer development services including aptamer screening, conjugation, modifications, characterization, and in vitro and in vivo analysis services. Aided by cell-based SELEX technology, we allow the discovery of aptamers that specifically bind to molecular targets on the surface of cells.

Get your high-affinity aptamers by sending us target cells and control cells.

Service Item	Description	Time
Preparation of an ssDNA/RNA library	Chemically synthesize an ssDNA/RNA library with the capacity of 1×10¹³ to 1×10¹⁵	1 week
In vitroselection	Target incubation, binding sequence elution, and amplification; Repeat above procedures for 3~4 times to select target-bound sequences; Negative selection using counter-target is sometimes required to improve the specificity of target sequences	~4-5 weeks
NGS sequencing	Utilizing NGS sequencing, bioinformatics, and biophysical methods to obtain basic information of the candidate.	2 weeks
Aptamer synthesis	High-quality Aptamer synthesis and purification by HPLC, with MS report	1 week
Modifications	Different needs and applications chose different modifying methods, such as biotin, 5’-NH₂, 5’-thiol, Fluorescent dyes…	2 weeks
Binding affinity test	Technologies like flow cytometry, ITC, SPR, QCM, etc. are used for KD determination.	1 week

Advantages

Excellent scientists providing a variety of solutions for aptamer development
Advanced technical platform to meet the requirement of different projects
Real-time guidance from start to finish of the project
One-stop services to remove your worries

If you are interested in our whole cell-based SELEX services for aptamer development, please contact us for more details.

Reference

Chen, M.; et al. Development of cell-SELEX technology and its application in cancer diagnosis and therapy. Int J Mol Sci. 2016, 17(12):2079.

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Aptamer Products List

Questions & Answer

A: Whole-cell-based SELEX allows for the selection of aptamers that specifically target surface proteins on live cells, making it valuable for applications like targeted drug delivery and diagnostics. It offers a more biologically relevant approach compared to traditional SELEX.

A: Whole-cell SELEX can be applied to various types of cells, including cancer cells, bacteria, and immune cells. The choice of the cell target depends on the specific research goals, such as identifying aptamers for disease biomarkers or therapeutic targeting.

A: Bioinformatics tools are essential for analyzing aptamer sequences, predicting secondary structures, and designing optimized aptamers. Computational approaches help in identifying potential binding sites on cell surface molecules.

For Research Use Only.