Access Type

Open Access Dissertation

Date of Award

January 2017

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Chemical Engineering and Materials Science

First Advisor

Guangzhao Mao

Abstract

Layer-by-Layer (LbL) gene delivery system is fabricated by polycation and plasmid DNA alternative deposition based on electrostatic force between each other. This dissertation explored the relationship between LbL film assembly and disassembly. Demonstrated that the film disassemble process is closely related to film interior structure. LbL interlayer diffusion, which is caused by the polyelectrolytes own properties, such as polymer chain length, molecular weight, and charge density, can influence film growth mode. The interlayer diffusion is the main reason to lead fast and bulk DNA releasing of bioreducible LbL film. Preventing interlayer diffusion by inserting small diffusion coefficient polymer, such as Polyethylenimine (PEI), can effectively achieve sustained and sequential DNA releasing. This dissertation also developed a series of poly(amido amine)s (PAAs) with high transfection efficiency and biocompatibility for LbL film design. Through polycation/DNA polyplex experiment, we obtained a type of PAA, pAPOL-1, with high buffer capacity, reasonable degradation rate, and low cytotoxicity. This pAPOL-1 can be incorporated into LbL film to build next generation localized delivery vehicle. The novel LbL film, LbL film 1, largely improved LbL film transfection efficiency and maintained low toxicity to HEK 293 and MC 3T3 cell lines. Small amount of PEI inserted into LbL film acting as barrier layer successfully screened the residue charge, stabilized film interior layer structure, and slowed down the degradation rate. The LbL film 1 provides a promising method for multiple therapeutic gene delivering in desired order. Study of introducing therapeutic gene in vivo described in this dissertation also make contributions to the development of gene therapy. In conclusion, bioreducible LbL films with high efficiency and low toxicity developed in this dissertation provides a sustained and sequential delivery method which can contribute to localized gene delivery application.

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