Daniela Donghia

Cell membranes are vital for living organisms and serve as a dynamic barrier between the internal and external environments. They are composed of a complex lipid bilayer embedded with proteins, allowing them to perform multiple functions like maintaining the cell structure, regulating which substances enter or leave the cell, and intercellular communication. Cellular functions are inherently linked to their membrane properties, and the heterogeneous nature of cell membranes makes the study of their physico-chemical properties extremely challenging. This review is intended to provide a comprehensive overview of the composition and physical features of the cell membrane, by focusing on the lipid and protein composition, and on the physical properties (like membrane stiffness or fluidity), highlighting how these characteristics influence cell functions. An insight into the similarities and differences from the membranes of extracellular vesicles (naturally secreted by almost all cell types) is also provided. The understanding of the physico-chemical properties of cell membranes might find application in different therapeutic fields, like disease diagnosis and development of novel drug delivery systems. Therefore, an overview of the literature works describing the rational design of biomimetic drug delivery systems is presented, focusing on the choice of lipid components, frequently inspired by the study of the composition of naturally secreted exosomes, and on the physical characterization of the systems. In the future, in-depth study of biologic vesicles might lead to the development of promising formulation for drug delivery, possibly enhancing the therapeutic outcomes of many pathologies, like cancer.

The majority of anticancer agents currently used derive from natural sources: plants, frequently the ones employed in traditional medicines, are an abundant source of mono- and diterpenes, polyphenols, and alkaloids that exert antitumor activity through diverse mechanisms. Unfortunately, many of these molecules are affected by poor pharmacokinetics and limited specificity, shortcomings that may be overcome by incorporating them into nanovehicles. Cell-derived nanovesicles have recently risen to prominence, due to their biocompatibility, low immunogenicity and, above all, targeting properties. However, due to difficult scalability, the industrial production of biologically-derived vesicles and consequent application in clinics is difficult. As an efficient alternative, bioinspired vesicles deriving from the hybridization of cell-derived and artificial membranes have been conceived, revealing high flexibility and appropriate drug delivery ability. In this review, the most recent advances in the application of these vesicles to the targeted delivery of anticancer actives obtained from plants are presented, with specific focus on vehicle manufacture and characterization, and effectiveness evaluation performed through in vitro and in vivo assays. The emerging overall outlook appears promising in terms of efficient drug loading and selective targeting of tumor cells, suggesting further engrossing developments in the future.