Systemic gene delivery using lipid envelope systems and its potential in overcoming challenges

Nonviral vectors which offer a safer and versatile alternative to viral vectors have been developed to overcome problems caused by viral carriers. However, their transfection efficacy or level of expression is substantially lower than viral vectors. Among various nonviral gene vectors, lipid envelops systems are an ideal platform for the incorporation of safety and efficacy into a single delivery system. Emerging strategies for gene delivery using lipid-based delivery systems mainly aim at improving the transfection efficiency and potency while reducing toxicity, achieving prolonged release, cell-specific targeting, co-delivery of drug and gene. Earlier efforts to improve the transfection efficiency while overcoming the toxicity led to the need for preparing conjugates of lipids with polyamines. In this review, we highlight current lipidic vectors that have been developed for gene therapy, challenges, and their solutions.