m-dPEG®₂₅-amido-dPEG®₂₄-DSPE

m-dPEG®25-amido-dPEG®24-DSPE, product number 11095 (PN11095), modifies the lipid 1,2-Distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) with a methoxy-terminated, single molecular weight, discrete polyethylene glycol (dPEG®). This product is designed to protect liposomes and micelles from opsonization and elimination by the reticuloendothelial system (RES).

Liposomes and Micelles
As carriers of cytotoxic agents, labels, and imaging agents, liposomes and micelles have revolutionized pharmaceutics and medical diagnostics. Operating either passively or actively through ligand-receptor targeting, liposomal and micellar nanoparticles with diameters of 30 – 200 nm possess several desirable features for payload delivery. These features include good stability in vivo and in vitro; extended circulation in the bloodstream, increased tumor accumulation through the enhanced permeability and retention (EPR) effect; and reduced systemic toxicity, since cytotoxic agents are sequestered from cells until delivery through membrane fusion. To date, several different liposomal and micellar formulations have been approved for clinical use.

In vivo, liposomes and micelles used as nanocarriers are susceptible to opsonization and removal from the bloodstream through the RES, also known as the mononuclear phagocytic system (MPS). Polyethylene glycol (PEG) is the most commonly used surface coating of liposomes and micelles. Covalent attachment of PEG (PEGylation) to liposomal and micellar surfaces provides a "stealth" character to the coated surfaces that decreases or abolishes opsonization. Therefore, PEGylation protects the coated material from removal by the RES.
PEGylation of Liposomes and Micelles
Traditional PEG is a polymer. Accordingly, polymeric PEG is dispersed (Đ > 1) and consists of a complex mixture of different chain lengths and molecular weights. In contrast, our dPEG® products are single molecular weight compounds. Each dPEG® product contains a single, discrete PEG chain (Đ = 1). This results in a uniform product that is easier to analyze and use.

Liposomes and micelles are often coated with traditional, polymeric PEG2000 (a polymer PEG having an average molecular weight of 2,000 Daltons) at a density of about 5 – 8 mole%. PN11095, m-dPEG®25-amido-dPEG®24-DSPE is equivalent to a methoxy-terminated PEG2000. Unlike a traditional PEG2000, however, PN11095 is a single product. That is, the product consists of a single, discrete-length PEG chain conjugated to DSPE, giving a product with a single molecular weight rather than an averaged molecular weight.

PN11095, m-dPEG®25-amido-dPEG®24-DSPE can be used as a standalone surface coating of liposomes and micelles to provide protection from opsonization and removal by the RES. In addition, m-dPEG®25-amido-dPEG®24-DSPE can be mixed with other DSPE products from Quanta BioDesign that terminate with reactive groups (for example, maleimide) that can be modified by conjugation to targeting agents such as ligand-targeting peptides.

If you need bulk product in a larger package size than our standard sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.

Application References:

Hermanson, G. T. Chapter 18, PEGylation and Synthetic Polymer Modification. Bioconjugate Techniques, 3rd edition. Academic Press: New York, 2013, 787-838.
Hermanson, G. T. Chapter 21, Liposome Conjugates and Derivatives. Bioconjugate Techniques, 3rd edition. Academic Press: New York, 2013, 921-949.
Thau, L.; Mahajan, K. Physiology, Opsonization. In StatPearls; StatPearls Publishing: Treasure Island (FL), 2018.
Stefanick, J. F.; Ashley, J. D.; Kiziltepe, T.; Bilgicer, B. A Systematic Analysis of Peptide Linker Length and Liposomal Polyethylene Glycol Coating on Cellular Uptake of Peptide-Targeted Liposomes. ACS Nano 2013, 7(4), 2935–2947. https://doi.org/10.1021/nn305663e.
Stefanick, J. F.; Ashley, J. D.; Bilgicer, B. Enhanced Cellular Uptake of Peptide-Targeted Nanoparticles through Increased Peptide Hydrophilicity and Optimized Ethylene Glycol Peptide-Linker Length. ACS Nano 2013, 7(9), 8115–8127. https://doi.org/10.1021/nn4033954.
Noble, G. T.; Stefanick, J. F.; Ashley, J. D.; Kiziltepe, T.; Bilgicer, B. Ligand-Targeted Liposome Design: Challenges and Fundamental Considerations. Trends in Biotechnology 2014, 32(1), 32–45. https://doi.org/10.1016/j.tibtech.2013.09.007.
Saw, P. E.; Park, J.; Lee, E.; Ahn, S.; Lee, J.; Kim, H.; Kim, J.; Choi, M.; Farokhzad, O. C.; Jon, S. Effect of PEG Pairing on the Efficiency of Cancer-Targeting Liposomes. Theranostics 2015, 5(7), 746–754. https://doi.org/10.7150/thno.10732.
Bulbake, U.; Doppalapudi, S.; Kommineni, N.; Khan, W. Liposomal Formulations in Clinical Use: An Updated Review. Pharmaceutics 2017, 9(2), 12. https://doi.org/10.3390/pharmaceutics9020012.

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