Target recognition and binding of aptamers involves three-dimensional, shape-dependent interactions as well as hydrophobic interactions, base-stacking, and intercalation. Aptamers bind to a portion of their target in which they fit.
To date, oligonucleotide therapeutics have focused on gene silencing other strategies are being pursued, these including gene activation and splice modulation strategies which have the potential to expand therapeutics targets beyond what is generally accessible to conventional pharmaceutical modalities.
There are hundreds of oligonucleotide therapies currently in clinical development with several gaining regulatory approval. Despite this, difficulties remain in achieving efficient delivery to target organs and tissues.
The most commonly used strategies employed to improve nucleic acid drug delivery include chemical modification to improve ‘drug-likeness’, covalent conjugation to cell-targeting or cell-penetrating moieties and nanoparticle formulation, endogenous vesicle (exosome) loading, spherical nucleic acids (SNAs), nanotechnology applications (DNA cages).