Considering titanium dioxide nanoparticles (TiO₂ NPs) role in plant growth and especially in plant tolerance against abiotic stress, a greenhouse experiment was carried out to evaluate TiO₂ NPs effects (0, 50, 100 and 200 mg L⁻¹) on agronomic traits of Moldavian balm (Dracocephalum moldavica L.) plants grown under different salinity levels (0, 50 and 100 mM NaCl). Results demonstrated that all agronomic traits were negatively affected under all salinity levels but application of 100 mg L⁻¹ TiO₂ NPs mitigated these negative effects. TiO₂ NPs application on Moldavian balm grown under salt stress conditions improved all agronomic traits and increased antioxidant enzyme activity compared with plants grown under salinity without TiO₂ NP treatment. The application of TiO₂ NPs significantly lowered H₂O₂ concentration. In addition, highest essential oil content (1.19%) was obtained in 100 mg L⁻¹ TiO₂ NP-treated plants under control conditions. Comprehensive GC/MS analysis of essential oils showed that geranial, z-citral, geranyl acetate and geraniol were the dominant essential oil components. The highest amounts for geranial, geraniol and z-citral were obtained in 100 mg L⁻¹ TiO₂ NP-treated plants under control conditions. In conclusion, application of 100 mg L⁻¹ TiO₂ NPs could significantly ameliorate the salinity effects in Moldavian balm.

Cancer is the main cause of death worldwide. The limitations in traditional cancer therapies provoked the advance and use of several nanotechnologies for more effective and nontoxic cancer treatment. Along with synthetic nanocarriers, extracellular vesicles (EVs)-mediated drug delivery systems have aroused substantial interest. The term EVs refers to cell-derived nanovesicles, such as exosomes, with phospholipid-bound structures, participating in cell-to-cell communication. Exosomes are 30–150 nm vesicles that can transfer many biological molecules between cells. From a drug delivery standpoint, exosomes can be loaded with various therapeutic cargo, with the several advantages of low immunogenicity, high biocompatibility, transformative, and effective tumor targeting aptitude. The exosomal surface can be functionalized to improve tumor targeting ability of them. Researchers have genetically expressed or chemically linked various molecules on the surface of exosomes. Despite extensive investigation, clinical translation of exosome-based drug delivery remains challenging. In this review, we discuss various methods used to loading exosomes with therapeutic cargo. We describe examples of functionalized exosomes surface using genetic and chemical modification methods. Finally, this review attempts to provide future outlooks for exosome-based targeted drug delivery.