In the field of gene transfection, polyethylene oxide (PEI) has shown great potential and broad application prospects. It can tightly bind with nucleic acid molecules such as DNA or RNA through electrostatic interactions, forming stable polyethylene imine nucleic acid complexes. This complex can effectively protect nucleic acids from degradation by nucleases in the body. When the complex is taken up by cells, Polyethylene undergoes protonation in the acidic environment of the cell, producing the “proton sponge effect”. This helps the complex escape from the endosome and enter the cytoplasm, thereby achieving efficient gene transfection. Compared with traditional gene transfection reagents, PEI has the advantages of low cost, easy operation, and relatively high transfection efficiency. Therefore, it is widely used in basic gene function research, early exploration of gene therapy, and the construction of some experimental animal models.

The application of Polyethyleneimine in the field of water treatment is also gradually emerging. It has excellent flocculation performance and can neutralize the charges and adsorb and bridge with suspended particles, colloids and other impurities in water, forming larger flocs, thereby achieving rapid sedimentation and separation of impurities. Compared with traditional inorganic flocculants, Polyethyleneimine flocculants have the advantages of low dosage, good flocculation effect and environmental friendliness. In addition, PEI can also be used to prepare water treatment membrane materials. By modifying its surface, the hydrophilicity and anti-pollution performance of the membrane can be improved, and the selectivity and flux stability of the membrane can be enhanced, thereby more effectively achieving water filtration and purification. In some experimental studies on industrial wastewater treatment and drinking water purification, PEI-based flocculants and membrane materials have demonstrated good application potential and are expected to provide new ideas and methods for solving water resource shortage and water pollution problems.

Polyethyleneimine also finds uses in agriculture. It can act as an enhancer to pesticide products. Polyethyleneimine interacts with pesticide molecules to increase the adhesion and penetration of pesticides onto plant surfaces, thus increasing efficacy while simultaneously decreasing usage, environmental pollution, and costs associated with treatment.Meanwhile, polyethylene can also be used for seed treatment, by coating or modifying its surface, it can improve the stress resistance and germination rate of seeds, and promote plant growth and development. Some studies have shown that adding an appropriate amount of PEI in seed treatment can enhance the tolerance of seeds to adverse environmental conditions such as drought and salinity, which is of great significance for improving crop yield and quality, and also provides a possible auxiliary means for the sustainable development of agriculture.

The core competitiveness of Polyethylene comes from its unique molecular structure and controllable chemical properties. As a representative of cationic polymers, the densely distributed amino groups on their molecular chains endow the material with excellent charge neutralization ability, which makes it particularly prominent in scenarios requiring strong electrostatic interactions such as gene transfection and flocculation precipitation. Compared with natural peptides or polysaccharides, the synthetic route of Polyethylene is mature, the batch stability is high, and cost control can be achieved through industrial production, which is crucial for water treatment or papermaking industries that require large-scale applications.

Regarding biocompatibility, while early studies may have demonstrated that high-molecular-weight Polyethyleneimine has some cytotoxicity properties, this defect can be effectively improved through chemical modification or combination with other materials. Polyethylene glycol segments can reduce non-specific interactions between polymers and cell membranes, while pairing it with chitosan can take advantage of its biodegradability to lower risks of toxicity.This flexible functionalization strategy enables Polyethyleneimine to gradually meet the biosafety requirements of clinical applications while maintaining its efficient delivery capacity.

Environmental benefits of Polyethyleneimine polymers over traditional synthetic polymers are another significant advantage. Although nonbiodegradable in itself, photosensitive groups or ester bonds can be introduced through molecular design to make the molecules biodegrade under specific circumstances (for example ultraviolet light or hydrolysis). This controllable degradation property not only meets the performance requirements of the use stage, but also reduces the environmental residual risk of the material. In addition, during the production process, Polyethyleneimine can achieve the recycling of solvents and unreacted monomers through a closed-loop process, which is in line with the development concept of green chemistry. Compared with flocculants containing heavy metals or petroleum-based polymers that are difficult to recycle, the eco-friendly properties of Polyethyleneimine add an important weight to its application in the field of sustainable development.

Functional expansion driven by technological innovation has further consolidated the market position of Polyethyleneimine. By compounding with other materials (such as inorganic nanoparticles, carbon materials, and natural polymers), hybrid systems with multiple properties can be developed. For example, the polyethyleneimine/graphene composite material not only retains the high conductivity of graphene, but also enhances the compatibility with the polymer matrix through the interface modification of polyethyleneimine; the polyethyleneimine functionalized magnetic nanoparticles combine the dual advantages of rapid magnetic separation and efficient adsorption, showing unique value in pollutant removal or targeted drug delivery. This multi-dimensional performance integration capability keeps polyethyleneimine at the forefront of functional polymer research and provides innovative ideas for solving complex engineering problems.