Abstract

Gene delivery into cells offers opportunities to treat various human genetic diseases. Effective gene delivery is dependent on its stability and ability to transfect across cells. DNA is susceptible to enzymatic degradation and its negatively charge are barriers towards successful transfection. DNA has to be protected from degradation and neutralised. Non-viral vectors are preferred carrier systems, therefore, the use of cyclodextrins with Pluronic^®-F127 and folic acid at different concentrations to stabilise the formulation was investigated. Formulations were characterised in fresh and freeze dried forms. DNA stability in formulations was tested by determining the stability of DNA against enzymatic degradation. Degree of DNA inclusion into cyclodextrins was investigated using fluorescence spectroscopy. Thermal behaviour was studied using Differential Scanning Calorimetry (DSC). Incorporation of Pluronic^®-F127 produced most stable formulations regarding enzymatic degradation. These formulations show high percentage inclusion. Shift of peaks in FTIR data, appearance of uniform particulate as detected by SEM and changing in the denaturation temperature as demonstrated by DSC data for Pluronic^®-F127 containing formulations confirm clear interaction between Pluronic^®-F127 and cyclodextrin/ DNA complex. It was noted that γ-cyclodextrin provide better protection and inclusion compared to β-cyclodextrin. Pluronic^®-F127 with cyclodextrins is a promising combination to improve stability.

Keywords: Cyclodextrin, deoxyribonucleic acid (DNA), DNA degradation, gene delivery, non-viral vectors, Pluronic^®-F127.