BOC Sciences provides you with labeling modification services for oligonucleotides, including base modification, labeling modification, cholesterol labeling, and so on. Among them, cholesterol labeling of oligonucleotides can be used to increase the lipophilicity of oligonucleotides, thus expanding the applications of oligonucleotides in biomedicine.
Cholesterol is a lipid compound that is widely found in animal cells. It interacts with phospholipid molecules to regulate the fluidity and stability of cell membranes. The presence of cholesterol can affect the permeability and permeability of cell membranes, as well as the exchange of substances inside and outside the cell.
Since cholesterol is an important component of cell membranes, it is highly lipophilic. By binding cholesterol to the oligonucleotide, the lipophilicity of the oligonucleotide can be increased, making it easier to cross the cell membrane and enter the cell. This modification can increase the efficiency of cellular uptake of the oligonucleotide, thereby enhancing its biological activity. In addition, cholesterol modification increases the stability of the oligonucleotide, improves the efficiency of targeted delivery(such as Cholesterol-siRNA Conjugation), and extends its half-life in vivo.
Fig 1. Structure of cholesterol-conjugated antisense oligonucleotides. (Wada et al., 2016)
The cholesterol type modification labeling position can be either the 5' or 3' end of the oligonucleotide. Generally, we choose the 5' end modification. 5' cholesterol modification produces a mixture of modified and unmodified oligonucleotides. As a result, two bands are usually visible on the gel photo after 5' labeling. One band represents the full-length unmodified oligonucleotide and the other band represents the full-length modified oligonucleotide. In general, cholesterol-modified oligonucleotides may be difficult to dissolve in aqueous solutions. In most cases, a freeze/thaw cycle may help to dissolve the oligonucleotide into solution. We will retain the cholesterol-modified oligonucleotide in solution and optimally purify it.
BOC Sciences can purify cholesterol-modified oligonucleotides using a variety of techniques.
RP-HPLC utilizes the difference in hydrophilicity between the oligonucleotide and the stationary phase for separation.
Since oligonucleotides may differ in molecular size from cholesterol-modified oligonucleotides, they can be separated and purified using gel columns.
If the cholesterol-modified oligonucleotide binds specifically to a particular affinity agent, it can be separated and purified using affinity chromatography.
Small molecule impurities such as salt ions and unreacted reagents can be removed from the oligonucleotide solution by dialysis.
Quality control is a critical step in ensuring the quality of the product during the purification of cholesterol-modified oligonucleotides, and BOC Sciences strictly controls the quality of each oligonucleotide synthesized through the use of mass spectrometry or polyacrylamide gel electrophoresis (PAGE) analysis. In addition, we perform impurity analysis to detect residues of reagents and protecting groups used during synthesis and modification to ensure that their limits in the final product are met.
BOC Sciences is committed to providing comprehensive customized cholesterol-labeled oligonucleotide services within tight deadlines, at reasonable prices, and with stringent quality control of our products. If you are interested in our services, feel free to contact us.
Reference
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