Physical approaches for drug delivery: An overview. An overview.

Delivery of exogenous materials or cargo such as drugs, proteins, peptides, and nucleic acids into cells is a vital segment in molecular and cellular biology for potential cellular therapy and drug-discovery applications contributing toward personalization of medicine. Over the years, drug-delivery techniques have been developed in order to gain more control over the drug dosage, targeted delivery, and to minimize side effects. The major drug-delivery techniques can be classified as viral, chemical, and physical methods. Viral vectors are prominently used for gene therapy; however, they are cell-specific and have an immune response with high toxicity. Chemical methods are often limited by the low efficiency of plasmid delivery into different cell types due to plasmid degradation and toxicity. Considering these limitations, different physical methods such as photoporation, gene gun, hydrodynamic injection, electroporation, and mechanoporation, etc., are being widely developed for highly efficient cargo delivery with low toxicity. These methods are able to create transient hydrophilic membrane pores to deliver cargos into cells using different physical energies. Currently, ex vivo cargo delivery is widely studied while few in vivo applications have been developed. Concerning several obstacles to cargo delivery into cells, this chapter mainly focuses on different physical drug-delivery techniques such as electroporation, optoporation, mechanoporation, magnetoporation, and hybrid techniques along with their working mechanisms, advantages, disadvantages, and limitations. An insight into the future prospects and real-time applications of these techniques is also discussed.