Synthesis of Poly(butylcyanoacrylate) Nanocapsules by Interfacial Polymerization in Miniemulsions for the Delivery of DNA Molecules

Monodispersed biodegradable poly(n-butylcyanoacrylate) nanocapsules containing DNA molecules (790 base pairs) within an aqueous core were prepared by anionic polymerization of n-butylcyanoacrylate at the droplets interface in inverse miniemulsion. The aqueous droplets in the size range of 300-700 nm dispersed in the hydrophobic continuous phase were formulated using the miniemulsion technique that allows an easy control of the droplet size and size distribution. After polymerization, the capsules were transferred into an aqueous phase. The effect of several reaction parameters such as the amount of monomer, type of the non-ionic surfactant (i.e. Span(R)80 and Tween(R)80) and type of the continuous phase (i.e. Miglyol 812N and cyclohexane) on the shell thickness, capsule size, morphology, polymer molecular weight, and encapsulation efficiency of DNA was investigated. The obtained results indicated that the type of the continuous phase has the largest influence on the capsule average size and polydispersity, whereas the shell thickness and morphology were mainly dependent on the monomer concentration. The encapsulation efficiency of DNA was about 100%, regardless to the surfactant type. At least, about 15% of the total DNA amount was found to be in the form of free chains.