Aptamers are single-stranded RNA or DNA oligonucleotides capable of forming specific 3D structures and binding very specifically to target molecules, such as proteins. Due to this ability, aptamers are often compared to antibodies, and some authors even refer to them as chemical antibodies. Where and how can they be used in practice?
The greatest successes of aptamer-based drugs have been recorded in the treatment of ophthalmological diseases. The very first drug of this type was approved by the FDA in 2004 and targets vascular endothelial growth factor. By binding to it, the drug inhibits the interaction of this factor with its receptor, thereby suppressing pathological angiogenesis in the treatment of the wet form of age-related macular degeneration.
It took nearly 20 years for the FDA to approve a second drug containing an aptamer as the active substance in 2023. In this case, the drug works by inhibiting complement function through targeting its C5 component, and it is approved for the treatment of geographic atrophy associated with age-related macular degeneration.
However, many current studies focus on the potential use of aptamers in treating cancer, immunological diseases, and viral or bacterial infections.
Alongside the use of aptamers as active agents, the idea emerged to exploit their high specificity for targeted delivery of other molecules to specific sites of action. In such cases, for example, a chemotherapy drug molecule could be bound to an aptamer that recognizes structures typical only of cancer cells.
Antibodies are already successfully used for this purpose, but aptamers offer a range of advantages. These include significantly lower immunogenicity compared to antibodies, better tissue penetration due to their relatively low molecular weight (5–20 kDa vs. 150 kDa for antibodies), and a simpler manufacturing process that does not require biological systems. This targeting principle can also be used in various imaging techniques.
All the above-mentioned properties of aptamers, especially their ability to bind target molecules specifically, make them very promising components for the design of diagnostic kits and various types of biosensors.
Here, too, these molecules compete with antibodies, as evident from the development of techniques similar to the well-known and clinically indispensable ELISA (Enzyme-Linked Immunosorbent Assay) methods. In such cases, the role of the antibody in the kit is fulfilled by a suitable aptamer.
An example of successful aptamer use is the design of a COVID-19 diagnostic kit, which in some aspects even outperformed traditional antibody-based sets.
With the growing number of potential applications for aptamers, several issues have emerged that must be resolved before the full potential of these molecules can be realized. Identifying the structure of an aptamer specific to a desired molecule is already a highly complex process.
Therefore, various experimental methods are currently being developed which, in combination with modern computational approaches and artificial intelligence tools, could simplify the search process or even enable the direct design of suitable aptamer structures. At the same time, many scientific teams are working on optimizing the selectivity, stability, and pharmacokinetic properties of aptamers.
Editorial Team, Medscope.pro
Sources:
1. Alsaidan O. A. Recent advancements in aptamers as promising nanotool for therapeutic and diagnostic applications. Analytical Biochemistry 2025, 702 : 115844, doi: 10.1016/j.ab.2025.115844.
2. Mohsen M. G., Midy M. K., Balaji A., Breaker R. R. Exploiting natural riboswitches for aptamer engineering and validation. Nucleic Acids Research 2023, 51 (2): 966–981, doi: 10.1093/nar/gkac1218.
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