Aptamer synthesis

 

Aptamers, an alternative to antibodies

Advantages:

• Chemically synthesized: cheap and easy to produce
• No organisms involved: GMP easy
• Low/non-immunogenic targets can be addressed
• Can be selected under non-physiologic conditions
• Easily modified for chemical conjugation, labeling, other properties
• Small size: good transport, more moles/gram
• Stable: no cold chain required

What are Aptamers ?

Aptamers are single-stranded DNA or RNA molecules that can bind to pre-selected targets including proteins and peptides with high affinity and specificity

These molecules can assume a variety of shapes due to their propensity to form helices and single-stranded loops, explaining their versatility in binding to diverse targets.

Contrary to the actual genetic material, their specificity and characteristics are not directly determined by their primary sequence, but instead by their tertiary structure.


Comparison Aptamers / Antibodies:

Aptamers		Antibodies
Chemical synthesis: no batch to batch variation of activity, large production volume		Biological synthesis
Use under a variety of conditions		Use limited to physiologic conditions
Selection against a wide range of targets		Selection limited to immunogenic targets
No secondary reagent needed		Secondary antibody is needed
Stable in harsh condition		Difficult for apply to harsh condition
Easy for chemical modification (dyes, thiol, biotine...)		Difficult for chemical modification
Small size (<30 kDa): easy membrane penetration		Large size (~150 kDa): difficult membrane penetration
Unlimited shelf-life		Limited shelf-life

Applications:

• Biosensors and novel assays
• Lateral flow assays
• Western blotting
• ELISA/ELONA
• Flow cytometry
• Therapeutics and drug delivery including siRNA