Kuk Cho - Academia.edu (original) (raw)

Papers by Kuk Cho

Biological & Pharmaceutical Bulletin, 2003

Nonviral delivery systems based on DNA complexes with polycations have recently generated siginif... more Nonviral delivery systems based on DNA complexes with polycations have recently generated siginificant interest in gene delivery systems. In the gene delivery system using nonviral vectors, polyethylenimine (PEI) was shown to be a useful carrier capable of condensing and delivering DNA in vitro and in vivo. 1-3) PEI forms polymer-DNA complexes that are stable against a aggregation in physiological buffer conditions and has a strong buffering capacity at almost any pH owing to the numerous number of primary, secondary and tertiary amino groups, 4) resulting in the potentially excellent safety profile of such complexes. However, there are still many issues to be dealt with such as the transfection efficiency, aggregation and half-life in the bloodstream, biocompatibility with less cytotoxicity, and solubility problems due to charge neutralization. To overcome such problems, some research groups proposed the use of cationic carriers with block or graft copolymer architecture consisting of polycationic polymers linked to a nonionic water-soluble polymer such as polyethylene glycol (PEG). 5-7) PEG has been used in many drug delivery systems because of its high solubility in water, nonimmunogenicity, and improved biocompatibility. In gene delivery systems, PEG has also been coupled to polycationic polymers 9) or liposomes 10) to improve the solubility of complexes and transfection efficiency. It is also possible to incorporate receptor-binding moieties such as antibodies into PEI to target certain tissues, 11,12) including tumors. 13) However, to the best of our knowledge, there has been no systematic study on the effect of the length of the PEG side chain on gene delivery and the stability of cationic polymer-DNA complexes with salt.

Biological & Pharmaceutical Bulletin, 2003

Nonviral delivery systems based on DNA complexes with polycations have recently generated siginif... more Nonviral delivery systems based on DNA complexes with polycations have recently generated siginificant interest in gene delivery systems. In the gene delivery system using nonviral vectors, polyethylenimine (PEI) was shown to be a useful carrier capable of condensing and delivering DNA in vitro and in vivo. 1-3) PEI forms polymer-DNA complexes that are stable against a aggregation in physiological buffer conditions and has a strong buffering capacity at almost any pH owing to the numerous number of primary, secondary and tertiary amino groups, 4) resulting in the potentially excellent safety profile of such complexes. However, there are still many issues to be dealt with such as the transfection efficiency, aggregation and half-life in the bloodstream, biocompatibility with less cytotoxicity, and solubility problems due to charge neutralization. To overcome such problems, some research groups proposed the use of cationic carriers with block or graft copolymer architecture consisting of polycationic polymers linked to a nonionic water-soluble polymer such as polyethylene glycol (PEG). 5-7) PEG has been used in many drug delivery systems because of its high solubility in water, nonimmunogenicity, and improved biocompatibility. In gene delivery systems, PEG has also been coupled to polycationic polymers 9) or liposomes 10) to improve the solubility of complexes and transfection efficiency. It is also possible to incorporate receptor-binding moieties such as antibodies into PEI to target certain tissues, 11,12) including tumors. 13) However, to the best of our knowledge, there has been no systematic study on the effect of the length of the PEG side chain on gene delivery and the stability of cationic polymer-DNA complexes with salt.