**7. Viral-based nanoparticles**

In the case, the viral-based nanoparticles are reported to be useful for photodynamic therapy due to their simple manufacturing and good safety profile [66], also they have interesting characteristics such as to possess great diversity in their structural uniformity, functionalization, expression, and self-assembly. Viral-based nanoparticles are mostly seen as therapeutics adjuvants or excipients that promote, improve, start, and attenuate or avoid the toxicity of the loaded pharmaceutical drug or bioactive compound [67].

Alemzadeh E et al., 2018, discussed that viral-based nanoparticles possess several advantages over other drug carriers, which include biodegradability, biocompatibility, known structure in atomic level, capacity to attach to ligand with high control on structure, accessibility for genetic and chemical alteration and malleable methods of preparation [68].

Several RNA viruses have been used as drug carriers such as *Brome mosaic virus* (BMV), *Red clover necrotic mosaic virus* (RCNMV), *Cowpea mosaic virus* (CPMV), *Cucumber mosaic virus* (CMV), *Hibiscus chlorotic ringspot virus* (HCRSV), *Tobacco mosaic virus* (TMV), *Potato virus X* (PVX), which have icosahedral and helical symmetries, from the pharmaceutical drugs loaded in these particles can be included doxorubicin, proflavine, DAPI, propidium iodide, acridine orange, polystyrene sulfonic acid, polyacrylic acid, phenanthriplatin, Herceptin, among others [68, 69].
