In vitro evaluation of a cationic polymer-lipid conjugate as a potential nanosystem for gene delivery

• Amphiphilic and cationic nano-polyplexes, potential for both genetic and drug molecules delivery. • Sustained and controlled gene release, crucial for sustained therapeutic availability. • Nano-polyplex has a higher genetic cargo capacity compared to commonly used AAV vectors. • Sustained biocompatibility, gene transfection and successful gene expression. Gene therapy aims to address the underlying cause of diseases by introducing a functional copy of a gene or enabling precise gene editing, offering the potential for long-term, sustainable solutions. This approach is particularly advantageous for inherited genetic conditions, chronic diseases with limited treatment options and conditions that would benefit from the modification of specific cells to offer a personalised therapeutic approach. Advantageously, gene therapy can bypass existing barriers through direct delivery to the affected tissues and provide one-time treatment options with lasting effects. Herein, a hybrid gene delivery nano-polyplex with sustained nucleic acid release properties was constructed for in vitro green fluorescent protein expression and biocompatibility analysis. The nano-polyplex system was synthesised using a combination of biocompatible polymers and lipids, which act as a delivery system entrapping nucleic acid primarily via electrostatic interactions. Formulations were selected to determine the influence of the nano-polyplex charge on encapsulation efficiency, in vitro transfection in HEK 293 and hRPE cells, and its safety profile. Different ratios of the nano-polyplex showed excellent complexation efficiency and protection from nucleic acid endonucleases. Sustained release of the genetic payload was shown for a period exceeding 96 h, and positive transfection efficiency in HEK 293 cells was detected by green fluorescent protein expression, detected by fluorescence microscopy, quantitative polymerase chain reaction, and flow cytometry. The nano-polyplex at different ratios proved to be biocompatible and capable of achieving sustained nucleic acid release and gene expression in HEK 293 cells.