Synthesis and Characterization of High-Molecular Mass Polyethylene Glycol-Conjugated Oligonucleotides

Abstract

The use of synthetic oligonucleotides as possible drugs for human therapy is usually hampered by their low in vivo stability and capacity to achieve high concentrations at their cellular targets. To overcome this, it has been suggested that they be modified chemically. Among the various options, conjugation with short- and long-chain polyethylene glycols (PEGs) has several advantages: PEG is nontoxic and very soluble, reduces immunogenic reactions, and increases the stability of the conjugated molecules. PEG is generally joined to oligonucleotides while bound to the insoluble solid-phase supports, after their synthesis, which does not allow for their being easy scaled up. The use of the liquid-phase approach as an alternative synthetic process, utilizing the PEG polymer both as a soluble, inert synthetic support and a stabilizing agent of the oligonucleotide, is proposed. A new protocol has been set up, characterized by a stable phosphate bond between the support and the oligonucleotide. This method has been tested on a 12mer previously investigated as an antisense agent against HIV. The PEG-conjugated 12mer was efficiently synthesized and purified. It was found that the high-molecular mass PEG chain results in enzymatic stability and does not interfere with the formation of the duplex with its nucleic acid target.

Dendrimer-Modified Magnetic Nanoparticles Enhance Efficiency of Gene Delivery System

“…However, antisense therapy is still restricted in application of clinical therapy because of two existing problems, such as rapid degradation by exonuclease or endonuclease and poor diffusion across the cell membrane (17)(18)(19). Although some methods, such as chemically modified oligonucleotides, oligonucleotides bound to virus and synthetic carriers, and small interfering RNA, have been explored to solve these problems (20,21), so far no optimal solution is established. Therefore, looking for more effective alternative delivery system for antisense nucleotides is the key to solve the present problems.…”

Site-Specific Chemical Modification of Human Serum Albumin with Polyethylene Glycol Prolongs Half-life and Improves Intravascular Retention in Mice

“…e-mail: fswang@sdu.edu.cn thus reduce the extravasation. 9,10) This type of albumin could not only prevent the interstitial edema but also reduce the infusion frequency, which is valuable to decrease the mount required in clinical use indirectly and further alleviates the problem of short supply of plasma donor.…”

Bioconjugation of Oligonucleotides for Treating Liver Fibrosis

“…However, these synthesis strategies do not allow easy upscaling. Subsequently, the use of the liquid-phase approach utilizing the PEG polymer as support became possible (491,492) and has been used for the large scale synthesis of PEGylated ODNs. PEG is used as a soluble, inert synthetic support, onto which nucleosides are added sequentially using phosphoramidite-based procedure.…”