Abstract
Gene therapy could be simply defined as a strategy for the introduction of a functional copy of desired genes in patients, to correct some specific mutation and potentially treat the respective disorder. However, this straightforward definition hides very complex processes related to the design and preparation of the therapeutic genes, as well as the development of suitable gene delivery systems. Within non-viral vectors, polymeric nanocarriers have offered an ideal platform to be applied as gene delivery systems. Concerning this, the main goal of the study was to do a systematic evaluation on the formulation of pDNA delivery systems based on the complexation of different sized plasmids with chitosan (CH) or polyethyleneimine (PEI) polymers to search for the best option regarding encapsulation efficiency, surface charge, size, and delivery ability. The cytotoxicity and the transfection efficiency of these systems were accessed and, for the best p53 encoding pDNA nanosystems, the ability to promote protein expression was also evaluated. Overall, it was showed that CH polyplexes are more efficient on transfection when compared with the PEI polyplexes, resulting in higher P53 protein expression. Cells transfected with CH/p53-pDNA polyplexes presented an increase of around 54.2% on P53 expression, while the transfection with the PEI/p53-pDNA polyplexes resulted in a 32% increase.
Highlights
Published: 5 March 2021Gene delivery is a complex procedure where several obstacles must be overcome to successfully reach the target cell
The work started with a screening of different pDNAs:CH/PEI ratios to evaluate which one could lead to higher pDNA encapsulation
Several cationic polymers have been used in the nanocarriers development, and in this work, different pDNA were conjugated with CH and PEI
Summary
Gene delivery is a complex procedure where several obstacles must be overcome to successfully reach the target cell. Even after reaching the target cell, the biological effect is dependent on the effective delivery to the nucleus, for gene expression. It is extremely important to develop delivery systems that can reunite all these characteristics being able to target the cell/tissue of interest, for instance by using a hydrophilic protective corona for minimizing the non-specific interactions [2]. Naked DNA could be directly injected, but this approach would be limited to tissues reachable by direct injections (like skin or muscle) and it is unsuitable for systemic delivery due to the presence of serum nuclease [3], which would immediately degrade the therapeutic gene. Viral vectors could be applied for transferring the genetic material into the host cells
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