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Updated: Aug 17, 2026
Intra-lymph Node Injection of Biodegradable Polymer Particles
Published on: January 2, 2014
The effect of methoxy-PEG chain length and molecular architecture on lymph node targeting of immuno-PEG liposomes
1Molecular Targeting and Polymer Toxicology Group, School of Pharmacy, University of Brighton, Brighton BN2 4GJ, UK. s.m.moghimi@brighton.ac.uk
Abstract:
The rate of drainage and lymphatic distribution of subcutaneously injected liposomes is controlled by inclusion of methoxypoly(ethyleneglycol), mPEG-phospholipid into the liposomal bilayer. The effect is most dramatic with liposomes containing 15 mol% mPEG-lipid, with an average PEG molecular mass of 350 Da. These vesicles are drained rapidly from the injection site into the initial lymphatics when compared to unmodified liposomes, and are retained more favourably by the scavengers of the regional lymph node. Liposomes decorated with longer surface mPEG chains (6.7 mol% of mPEG2000-lipid) exhibit faster drainage rates than vesicles having 15 mol% mPEG350-lipid in their lipid bilayer, but their lymph node retention is very poor. The lymph node retention of rapidly drained PEG-bearing vesicles was increased dramatically following conjugation of a non-specific IgG to the distal end of PEG, using a functionalized PEG2000 lipid. Adjusting the molecular architecture of surface mPEG and IgG-PEG chains to a "nearly overlapped mushroom" regime further enhanced target recognition of immuno-PEG2000 liposomes without compromising their drainage rate from the interstitium. The lymph node retention of these vesicles was further optimized by enriching their lipid bilayer with 20 mol% phosphatidylserine. These approaches have established important compositional and structural variables that control lymphatic targeting of immuno-PEG liposomes and their application in experimental medicine and biology is discussed.
Insights
Methoxy(polyethylene glycol) or mPEG-lipid inclusion controls liposome lymphatic distribution. Optimizing mPEG chain length and adding IgG enhances lymph node targeting for improved delivery.
Area of Science:
- Biotechnology
- Nanomedicine
- Pharmacology
Background:
- Liposome lymphatic distribution is crucial for drug delivery.
- Controlling liposome drainage and retention impacts therapeutic efficacy.
Purpose of the Study:
- To investigate how methoxy(polyethylene glycol) or mPEG-lipid composition affects liposome lymphatic targeting.
- To optimize immuno-PEG liposomes for enhanced lymph node delivery.
Main Methods:
- Systematic variation of mPEG-lipid content and molecular weight in liposomes.
- Assessment of liposome drainage and lymph node retention in vivo.
- Functionalization of PEGylated liposomes with IgG for targeted delivery.
Main Results:
- Liposomes with 15 mol% mPEG350-lipid showed rapid drainage and good lymph node retention.
- Longer mPEG chains (mPEG2000) improved drainage but reduced retention.
- IgG conjugation and specific PEG architecture (mushroom regime) enhanced lymph node targeting.
- Incorporation of phosphatidylserine further optimized retention.
Conclusions:
- Liposome surface modification with mPEG and IgG significantly influences lymphatic transport.
- Tailoring PEG architecture and lipid composition enables precise control over liposome lymph node accumulation.
- These findings provide a framework for developing advanced liposomal drug delivery systems.
