PS based Anionic Liposome Development Service

In the rapidly evolving landscape of lipid-based drug delivery systems, precision is paramount. Phosphatidylserine (PS)-based anionic liposomes have emerged as a sophisticated tool for hijacking natural biological pathways, specifically the recognition of apoptotic cells by the immune system. Creative Biolabs leverages decades of biophysical expertise to engineer high-fidelity PS-based liposomes, transforming complex immunological concepts into stable, reproducible, and highly effective delivery vehicles for your research.

Understanding PS-Based Anionic Liposomes

What Are PS-Based Anionic Liposomes?

Phosphatidylserine (PS) is an anionic phospholipid normally sequestered on the inner leaflet of the plasma membrane in healthy cells. During apoptosis (programmed cell death), PS translocates to the outer leaflet. PS-based liposomes are engineered vesicles that mimic this specific surface topography. By incorporating 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS) into a neutral lipid matrix (typically DOPC), these liposomes present a negative surface charge that is biologically significant, acting as a specific ligand for receptors on phagocytes.

Fig. 1 Schematic representation of phosphatidylserine (PS) and its distribution on normal and cancer cell.¹

Why Surface Charge Control is Critical

The efficacy of this interaction depends heavily on the Zeta Potential—the measure of the liposome's electrokinetic potential.

• High Negative Charge: Leads to rapid clearance by the Reticuloendothelial System (RES), useful for liver/spleen targeting.
• Tunable Ratios: By adjusting the molar ratio of DOPS to DOPC, the Zeta potential can be fine-tuned to modulate the rate of cellular uptake, allowing for controlled immunomodulation rather than simple clearance.

Why Anionic Systems Matter in Research

Researchers are increasingly turning to anionic systems to mitigate the adverse effects of cationic lipids, such as hemolysis and complement activation. By utilizing divalent cations (e.g., Ca²⁺, Mg²⁺) to bridge the negative lipid headgroups with negatively charged nucleic acids, PG-liposomes achieve high encapsulation efficiency without the cytotoxicity associated with permanent positive charges.

Comprehensive Formulation Development Services

Custom Molar Ratios & Zeta Potential Tuning

We develop liposomes with varying ratios of DOPS to DOPC to achieve the exact negative Zeta potential required for your study.

• Standard Ratios: 10:90, 30:70, 50:50 (DOPS:DOPC)
• High-Charge Formulations: Up to 100% DOPS for maximal macrophage uptake.
• Low-Charge Formulations: <5% PS for subtle immunomodulation.

Payload Encapsulation

Our scientists are experts in loading diverse cargoes into the aqueous core or the lipid bilayer:

• Genetic Material: mRNA, siRNA, and pDNA for gene therapy.
• Small Molecules: Chemotherapeutics and anti-inflammatory drugs.
• Proteins & Peptides: Antigens for vaccine development.

Comprehensive Characterization

Every batch undergoes rigorous quality control to ensure reproducibility:

• Particle Size: Standardized to ~100 nm (tunable from 50 nm to 200 nm).
• Polydispersity Index (PDI): Strictly controlled (<0.2) for uniform populations.
• Zeta Potential Analysis: Confirmation of surface charge magnitude.
• Stability Testing: Stability monitoring at 4°C to prevent hydrolysis and oxidation.

Workflow

Applications of PS-Based Liposomes in Modern Research

Our specialized formulations are driving innovation across diverse biomedical fields:

• Macrophage Depletion Studies: Utilizing the "Trojan Horse" strategy to deliver cytotoxic agents (e.g., clodronate) selectively to macrophages, enabling the study of immune system function and autoimmune diseases.
• Immunomodulation & Tolerance Induction: PS liposomes can induce an anti-inflammatory phenotype (M2 polarization) in macrophages, promoting the release of cytokines like TGF-β and IL-10. This is critical for research into atherosclerosis, Type 1 Diabetes, and transplant tolerance.
• Viral Entry & Inhibition Assays: Since many enveloped viruses use "apoptotic mimicry" to enter host cells, PS liposomes serve as essential decoys or competitive inhibitors for studying viral entry mechanisms.
• Gene Therapy Delivery: Acting as anionic carriers for specific genetic materials, facilitating endosomal uptake in phagocytic cells.

Why Choose Creative Biolabs for PS-Liposomes Development?

We combine deep biophysical knowledge with industrial scalability to solve the common challenges associated with anionic liposomes.

• Precise Zeta Potential Tuning: We don't just guess; we measure. Our ability to dial in exact molar ratios allows for reproducible surface charge profiles batch after batch.
• Stability in Ionic Solutions: Anionic liposomes often aggregate in high-salt buffers due to charge shielding. We optimize formulations to maintain stability in physiological ionic strength.
• Sterility & Endotoxin Control: All formulations are prepared under aseptic conditions, ensuring they are suitable for sensitive cell culture and in vivo applications.

Creative Biolabs is dedicated to advancing the frontiers of immunotherapy and drug delivery through superior lipid technology. Our PS-Based Anionic Liposomes Development Service offers the precision, stability, and biological fidelity required to move your research from concept to clinical reality. Contact our team for more information and to discuss your project

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