Abstract
In recent decades, the development and application of nonviral vectors, such as liposomes and lipidic nanoparticles, for gene therapy and drug delivery have seen substantial progress. The interest in the physicochemical properties and structures of the complexes liposome/DNA and liposome/RNA is due to their potential to substitute viruses as carriers of drugs or genetic material into cells with minimal cytotoxicity, which could lead to their use in gene therapy. Initially, cationic liposomes were utilized as nonviral DNA delivery vectors; subsequently, different molecules, such as polymers, were incorporated to enhance transfection efficiency. Additionally, liposome/protein complexes have been developed as nonviral vectors for the treatment of diseases. The most relevant internalization pathways of these vectors and the few transfection results obtained using targeted and nontargeted liposomes are discussed below. The high cytotoxicity of cationic liposomes represents a significant challenge for the development of gene therapy and drug delivery. Anionic liposomes offer a promising alternative to address the limitations of conventional cationic liposomes, including immune response, short circulation time, and low toxicity. This review will discuss the advantages of cationic liposomes and the novel anionic liposome-based systems that have emerged as a result. The advent of novel designs and manufacturing techniques has facilitated the development of innovative systems, designated as lipid nanoparticles (LNPs), which serve as highly efficacious regulators of the immune system.