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Published on: July 31, 2015
Cationic starch/pDNA nanocomplexes assembly and their nanostructure changes on gene transfection efficiency.
Hongwei Wang1, Xiaoxi Li2, Ling Chen1
1Ministry of Education Engineering Research Center of Starch & Protein Processing, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, 510640, China.
Researchers developed biocompatible cationic starch (CS) gene carriers that effectively deliver plasmid DNA (pDNA) into cells. Optimized CS with a specific molecular weight showed high transfection efficacy and low toxicity, offering a promising approach for gene therapy.
Area of Science:
- Biomaterials Science
- Gene Delivery Systems
- Nanotechnology
Background:
- Development of effective and non-toxic gene carriers is crucial for gene therapy.
- Starch-based materials offer biocompatibility and biodegradability advantages.
- Modifying starch with cationic groups enhances its ability to complex with nucleic acids.
Purpose of the Study:
- To engineer biocompatible, spermine-modified cationic starch (CS) gene carriers.
- To investigate the impact of CS molecular weight and aggregation on gene delivery efficacy.
- To evaluate the performance of CS/plasmid DNA (pDNA) nanocomplexes under simulated intracellular pH conditions.
Main Methods:
- Synthesis and characterization of spermine-modified cationic starch (CS) with varying molecular weights.
- Formation of CS/pDNA nanocomplexes via electrostatic interactions.
- Analysis of nanocomplex structural changes (size, zeta potential, shape, compactness) using Dynamic Light Scattering (DLS) and Small Angle X-ray Scattering (SAXS) under different pH conditions.
- Assessment of gene transfection efficacy in HepG2 cells and cytotoxicity evaluation.
Main Results:
- CS with a weight-average molecular weight (Mw) of approximately 6.337 × 10⁴ g/mol (CS2) exhibited the highest transfection efficacy (~30%) in HepG2 cells.
- CS2/pDNA nanocomplexes showed significantly low cytotoxicity.
- Acidic conditions (simulating endosomes) resulted in smaller, compact nanocomplexes, enhancing pDNA protection, while physiological pH led to larger, looser structures, promoting release.
Conclusions:
- Cationic starch with a specific molecular weight (around 6.0 × 10⁴ g/mol) is a promising biocompatible gene carrier.
- Controlling the internal nanostructure of polymer/gene nanocomplexes in response to pH is key for effective gene delivery.
- This study provides a foundation for designing advanced starch-based gene delivery systems.
