Table 2.
Properties of aptamers versus monoclonal antibodies
| Criteria | Aptamers | Monoclonal antibodies |
|---|---|---|
| Molecular weight/size |
Low molecular weight: 6–30 kDa (20–100 nucleotides) Around 2 nm |
High molecular weight: 150–180 kDa Around 15 nm |
| Potential targets | Wide range of possible targets: ions, organic molecules, nucleic acids, amino acids, carbohydrates, antibiotics, peptides, toxins, cells, … |
Only immunogenic molecules Few toxins |
| Generation and manufacture |
In vitro SELEX Around 2 to 8 weeks, but can be hours via HTS-SELEX Cost of selection around 4000$ Low risk of contamination Possible large-scale production The environmental parameters of selection can be modified |
In vivo biological system Around 6 months or longer Cost of selection around 8000$ for mouse antibody, and 20 000$ for rabbit antibody Potential contamination due to cells or animal-based production Large-scale production not available without deteriorating the quality of the final product The environmental parameters must match the physiological environment |
| Reproductibility | High reproducibility, no batch-to-batch variation | Significant batch-to-batch variation |
| Conservation |
Long shelf-life and stability Can be lyophilized, easily transported and stored at room temperature |
Limited shelf life, unstable Must be cooled for transportation and storage |
| Physical and thermal stability |
Resistant to high temperature Can be reversibly denatured Reusable |
Susceptible to temperature (even at Room temperature or 37 °C) Susceptible to irreversible denaturation Single use |
| Chemical modification | Wide variety of chemical modifications that are site-specific and easily performed during synthetis or before selection | Chemical modifications are limited, not site-specific and inconstant |
| Immunogenicity | None or low | High |
| Pharmacokinetics (tissue uptake, kidney filtration, nuclease degradation) |
Efficient entry into biological compartments, susceptible to renal filtration and nucleases Short circulating half-life Pharmacokinetic properties can be improved |
Limited access to many biological compartments, not susceptible to nucleases nor renal filtration Long circulating half-life Pharmacokinetic are not easily modified |
| Specific antidote | Yes | No |