DNA Encapsulation via Double Emulsion Like Process

Gene therapy is one of the advanced methods used for treatment of incurable diseases such as cancer, acquired immunodeficiency syndrome, cardiovascular and infectious diseases. However, the efficiency of gene therapy is directly related to the access of nucleic acid (DNA) to the nucleus avoiding its degradation via enzymatic effect. So, the challenge is the access of non-degradable gene into the target cell-nucleus. This goal can be achieved by encapsulating the selected gene in a polymer matrix in order to be protected from degradation. Accordingly, this work aims to encapsulate DNA model in the biodegradable polycaprolactone (PCL) particles using water in oil in water (W/O/W) double emulsion evaporation technique. Via this method, DNA solution was mixed with dichloromethane (DCM) solution containing PCL in order to obtain the first water in oil emulsion (W₁/O). Then, the obtained W₁/O emulsion was dispersed in the aqueous phase containing poly(vinyl alcohol) (PVA) as a stabilizing agent in order to obtain the final water in oil in water emulsion (W₁/O/W₂) after DCM evaporation. In this study a special attention was dedicated to study the effect of DNA concentration on the colloidal properties of the final particles, including hydrodynamic particles size, size distribution, and zeta potential, in addition to its encapsulation efficiency by the biodegradable PCL particles. The obtained results proved that the w/o/w double emulsion–evaporation technique is highly efficient for encapsulation of DNA in submicron (260 nm) PCL colloidal particles with high encapsulation efficiency.