Related Experiment Videos
Development of multicomponent DNA delivery systems based upon poly(amidoamine)-PEG co-polymers
Benjamin J Rackstraw1, Snjezana Stolnik, Stanley S Davis
1School of Pharmaceutical Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
Biochimica Et Biophysica Acta
|June 27, 2002
Summary
PEGylated polyamidoamine (PAA) polymers were explored for DNA delivery. Blends of PEGylated and non-PEGylated polymers formed stable complexes, but reduced cellular uptake limited their effectiveness for in vivo applications.
Area of Science:
- Biomaterials Science
- Polymer Chemistry
- Gene Delivery Systems
Background:
- Polyamidoamine (PAA) polymers are investigated for DNA delivery.
- PEGylation is a common strategy to improve colloidal properties of delivery systems.
Purpose of the Study:
- To evaluate PEGylated PAA polymers for steric stabilization of DNA delivery systems.
- To assess the impact of PEGylation on the colloidal properties and DNA binding of PAA polymers.
- To investigate polymer blends for improved DNA complex formation and stability.
Main Methods:
- Ethidium bromide displacement assays and DNA melting studies to assess DNA binding.
- Gel electrophoresis, turbidimetric analysis, and dynamic light scattering (PCS) for colloidal properties.
- Transmission electron microscopy (TEM) to evaluate complex morphology.
- Nuclease degradation assays to assess stability.
Main Results:
- PEGylated PAA (NG47) formed soluble complexes with DNA, unlike non-PEGylated PAA (NG49).
- TEM revealed poorly condensed, nuclease-susceptible complexes with excess PEG.
- Polymer blends of NG47 and NG49 formed complexes with desirable properties: small size, high density, low charge, and nuclease resistance.
- Both PEGylated polymer alone and polymer blends exhibited reduced polyfection activity due to low surface charge, hindering cellular uptake.
Conclusions:
- While PEGylation can improve colloidal stability, excess PEG leads to poor complex condensation and nuclease susceptibility.
- Polymer blends offer a strategy to achieve desirable complex properties, including nuclease resistance.
- Reduced polyfection activity in PEGylated systems and blends necessitates further optimization for effective in vivo gene delivery.