Oligoamines grafted hyperbranched polyether as high efficient and serum-tolerant gene vectors

Area of Science:

• Biomaterials Science
• Gene Therapy
• Polymer Chemistry

Background:

• Developing non-viral gene delivery vectors with low toxicity and high efficiency remains a challenge.
• Existing polycationic vectors, such as polyethyleneimine (PEI), often suffer from cytotoxicity and poor serum tolerance.
• Hyperbranched polyethers offer a promising scaffold for creating novel gene delivery systems.

Purpose of the Study:

• To synthesize and characterize oligoamines-grafted hyperbranched polyethers (oligoamines-g-HBP) as potential gene delivery vectors.
• To evaluate the in vitro cytotoxicity, DNA binding capability, protein adsorption resistance, transfection efficiency, and serum tolerance of the synthesized vectors.
• To investigate the influence of oligoamine structure on gene delivery performance.

Main Methods:

• Synthesis of COOH-functionalized hyperbranched poly(3-ethyl-3-oxetanemethanol).
• Conjugation of oligoamines, including triethylenetetramine (TETA) and tetraethylenepentamine (TEPA), to the hyperbranched polyether backbone.
• In vitro assessment of cytotoxicity using cell viability assays.
• Evaluation of DNA binding affinity and complex formation.
• Transfection efficiency assays in cell cultures.
• Serum tolerance studies by measuring transfection efficiency in the presence of varying serum concentrations.
• Confocal laser scanning microscopy to visualize DNA delivery into cell nuclei.

Main Results:

• Oligoamines-g-HBP exhibited good buffering capacity, strong DNA binding, and high resistance to protein adsorption.
• Compared to 25 kDa PEI, oligoamines-g-HBP demonstrated significantly lower in vitro cytotoxicity.
• TEPA-grafted hyperbranched polyether (TEPA-g-HBP) showed markedly higher transfection efficiency than 25 kDa PEI at equivalent N/P ratios.
• TEPA-g-HBP displayed significantly improved serum tolerance, maintaining high transfection efficiency even at 30% serum concentration.
• Confocal microscopy confirmed increased DNA delivery into cell nuclei with a higher number of secondary amino ethylene groups in the oligoamines.

Conclusions:

• Oligoamines-g-HBP represent a promising class of non-viral gene delivery vectors.
• These novel polycations offer a favorable balance of low toxicity, high transfection efficiency, and excellent serum tolerance.
• The structure of the grafted oligoamines, particularly the number of secondary amino ethylene groups, influences gene delivery performance.
• Oligoamines-g-HBP hold great potential for future clinical applications in gene therapy.