Abstract: Biodegradable multilayer films of alternating poly- L -lysine(PLL) and deoxyribonucleic acid(DNA) layers were fabricated onto quartz substrates by the layer-by-layer(LbL) self-assembly method. UV-Visible spectra showed that PLL and DNA can successfully be adsorbed and form multilayer films via LbL. Degradation experiments were carried out with enzymes. AFM was utilized to measure the changes of thickness of multilayer films. The gradual decrease of thickness of multilayer films with the increase of degradation time was observed. In our experiments, about 85% of films was degraded in 35 h. Our study provided a novel gene delivery system using LbL method,which may be applied to gene therapy.

Key words: Biodegradation, Poly-L-lysine, Gene Delivery, Layer-by-layer self-assembly