Metal-Coordinated Histidine-Functionalized Redox-Responsive Polyethyleneimine as a Smart Gene Delivery Vector

Area of Science:

• Biotechnology and Genetic Engineering
• Nanomedicine
• Molecular Biology

Background:

• Gene delivery and CRISPR technologies face challenges including serum inhibition and cytotoxicity.
• Existing vectors often struggle with delivering large plasmids and maintaining stability in serum-rich environments.
• There is a critical need for advanced vectors with improved safety and efficacy across diverse cell types.

Purpose of the Study:

• To engineer a novel multifunctional vector from polyethylenimine (PEI1.8k) for enhanced DNA delivery.
• To address limitations of serum inhibition and cytotoxicity in current gene delivery systems.
• To evaluate the transfection efficiency of the new vector with plasmids of varying sizes in multiple cell lines.

Main Methods:

• A multifunctional vector (PEI1.8k-S-S-His) was constructed by linking histidine to PEI1.8k via redox-responsive disulfide bonds.
• Metal ions (Co, Cu, Cd, Ni, Zn, Mn) were tested to optimize plasmid packaging and transfection.
• Transfection efficiency, cytotoxicity, and serum tolerance were assessed in HEK 293T, NIH/3T3, MCF7, and MSCs.

Main Results:

• PEI1.8k-S-S-His demonstrated high transfection efficiency for small and large plasmids in HEK 293T cells with negligible cytotoxicity.
• The vector showed significant transfection potential at low plasmid doses (0.5 µg) and high serum concentrations (5-30%).
• Manganese-functionalized PEI1.8k-S-S-His-Mn exhibited superior transfection efficiency, particularly for large plasmids in HEK 293T cells.

Conclusions:

• The novel PEI1.8k-S-S-His vector, especially when functionalized with manganese, offers robust DNA binding, efficient endosomal escape, and serum tolerance.
• The synergistic effects of metal coordination, redox-responsive bonds, and cationic polymer contribute to low cytotoxicity and high transfection rates.
• These advanced nanocarriers hold significant promise for therapeutic gene delivery applications.