In gene delivery, non-viral vectors have become the preferred carrier system for DNA delivery. They can overcome major viral issues such as immunogenicity and mutagenicity. Cationic lipid-mediated gene transfer is one of the most commonly used non-viral vectors, which have been shown to be a safe and effective carrier. However, their use in gene delivery often exhibits low transfection efficiency and stability. The aim of this study was to examine the effectiveness of novel non-viral gene delivery systems. This study has investigated the encapsulation and transfection efficiency of cationic liposomes prepared from DOTAP and carboxymethyl-β-cyclodextrin (CD). The encapsulation efficiency of the CD-lipoplex complexes were also studied with and without the addition of Pluronic-F127, using both microfluidic and thin film hydration methods. In vitro transfection efficiencies of these complexes were determined in COS7 and SH-SY5Y cell lines. Formulation stability was evaluated using liposomes size, zeta potential and polydispersity index. In addition, the external morphology was studied using transmission electron microcopy (TEM). Results revealed that formulations produced by microfluidic method had smaller, more uniform and homogenious size and zeta-potential as well as higher encapsulation efficiency when compared with liposomes manufactured by thin film hydration method. Overall, the results of this study show that carboxymethyl-β-cyclodextrin increased lipoplexes’ encapsulation efficiency using both NanoAssemblr and rotary evaporator manufacturing processes. However, this increase was reduced slightly following the addition of Pluronic-F127. The addition of carboxymethyl-β-cyclodextrin to cationic liposomes resulted in an increase in transfection efficiency in mammalian cell lines. However, this increase appeared to be cell line specific, COS7 showed higher transfection efficiency compared to SH-SY5Y.

pDNA/CM-β-CD complex has not only shown to be able to transfect COS 7 and SHSY5Y cell lines, but it gives a higher transfection efficiency than that produced by the TransIT-LT1 commercial transfection reagent.

The recent accomplishment of the human genome and DNA discovery has led to the diagnosis of many diseases caused by imperfections in genes. These diseases involve gross disturbances in the number or arrangement of a person's chromosomes. Hence, gene therapy has become a promising new therapy for the treatment of somatic diseases, for example, malignant tumours [1], severe infectious diseases, such as AIDS [2], and many genetic disorders, including haemophilia and cystic fibrosis [3]. Gene therapy introduces a gene into human cells to replace, delete, or correct gene function to produce a therapeutic protein with the desired action. This adjustable gene can be used to cure any disease. In 1990, a gene therapy clinic was initiated to find treatment for severe combined immunodeficiency (SCID). However, the first success of gene therapy was not observed until 2000 when Cavazzana calvo et al. [4] reported a success using gene therapy for the treatment of SCID [4]. While it has been 30 years since the first gene therapy trial, gene therapy is still a high-risk treatment, and only a few drugs have been approved, such as Glybera® , Gendicine®, and Strimvelis®.

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