Construction of hollow DNA/PLL microcapsule as a dual carrier for controlled delivery of DNA and drug

DNA/poly-L-lysine (PLL) capsules were constructed through a layer-by-layer (LbL) self-assembly of DNA and PLL on CaCO3 microparticles, and then used as dual carriers for DNA and drug after dissolution of carbonate cores. The permeability of DNA/PLL microcapsules was investigated with fluorescence probes with different molecular weights by confocal microscopy. The result revealed that the fluorescence probes were able to penetrate the capsule walls even its molecular weight up to 150 kDa. The resultant capsules were used to load drug model molecules-fluorescein isothiocyanate (FITC)–dextran (4 kDa) via spontaneous deposition mechanism. DNA/PLL capsules were used as dual drug carriers for concurrent delivery DNA and FITC–dextran molecules by salt-triggered capsule decomposition. The amount of released DNA and drug can be controlled by adjusting ionic strength. The larger salt concentration, the more DNA and drug were released. Two remedial agents could be simultaneously introduced to the diseased region by using this carrier system, which may really improve curative effect due to the synergetic effect of DNA and drug.