Vaccine Lab / Alfa Chemistry
Phosphatidylserine Series
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Phosphatidylserine Series

Phosphatidylserine, an essential constituent of eukaryotic membranes, is the most abundant anionic phospholipid in the eukaryotic cell accounting for up to 3-10% of the total cellular lipid. As in the case of other lipids, phosphatidylserine is not evenly present throughout all cellular membranes and is not equally distributed between the leaflets of each membrane bilayer. In resting cells plasmalemmal phosphatidylserine is found exclusively on the inner (cytoplasmic-facing) monolayer, due to the action of ATP-dependent amino phospholipid flippases. In addition to being a component of the lipid bilayer, phosphatidylserine has many additional functions. For example, it is also vital to the maintenance of the cell's internal environment, where it also participates in signal transduction, cell-to-cell communication, and cell growth regulation.

Structure of phosphatidylserine

Phosphatidylserine is a glycerophospholipid that consists of two fatty acids attached in ester linkage to the first and second carbon of glycerol and serine attached through a phosphodiester linkage to the third carbon of the glycerol. Phosphatidylserine has three ionizable groups, i.e., the phosphate moiety, the amino group, and the carboxyl group. As with other acidic lipids, it exists in nature in salt form, but it has a high propensity to chelate to calcium via the charged oxygen atoms of both the carboxyl and phosphate moieties, modifying the conformation of the polar head group.

Schematic representation of the common headgroups of phosphatidylserine at physiological conditions (RI and R2 represent fatty acyl chains and X represents serine).Figure 1. Schematic representation of the common headgroups of phosphatidylserine at physiological conditions (RI and R2 represent fatty acyl chains and X represents serine) [1].

Advantages of phosphatidylserine in lipid nanoparticles

Phosphatidylserine is the most abundant negatively charged phospholipid in eukaryotic membranes. Its presence provides several advantages for lipid nanoparticles (LNPs). The most notable advantage is that it increases the efficiency of the lipid-based nucleic acid delivery system. On the one hand, phosphatidylserine helps to improve the transfection efficiency and efficacy of pDNA- and mRNA-based LNPs. On the other hand, phosphatidylserine enhances the interaction with the scavenger receptors of the target cells, thereby enhancing the cellular uptake via clathrin-mediated endocytosis.

Schematic diagram of LNPs equipped with phosphatidylserine.Figure 2. Schematic diagram of LNPs equipped with phosphatidylserine [2].

What we offer

Alfa Chemistry supplies a wide range of phosphatidylserine products for companies researching vaccines. If you cannot find the product you need, please contact us. We also offer product customization according to customer's detailed requirements.


  1. Valente, C.; et al. Phosphatidic acid in membrane rearrangements. FEBS Letters. 2019, 593: 2428-2451.
  2. Incorporation of phosphatidylserine improves efficiency of lipid based gene delivery systems. Eur. J. Pharm. Biopharm. 2022, 172: 134-143.

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