Table 1.

Advantages and disadvantages of nanoparticles used for gene delivery.

Composition	Advantages	Disadvantages	Reference
Inorganic Nanoparticles
Metallic (Gold, iron)	Multiple forms (spherical, nanorods, triangles) Biocompatibility Tunable size Straightforward functionalization	More information about uptake, biocompatibility and low cytotoxicity are required for clinical translation	[19,147]
Silica	The structure could add high amounts of drugs and genes Tunable pore size	More information about cytotoxicity, biodistribution and biocompatibility are required for clinical translation	[148]
Carbon-derived	Large surface area High loading capacity Vast numbers of possibilities for surface modification	Few in vivo studies developed	[149,150,151]
Organic nanoparticles
Lipid-base (Liposomes)	Low toxicity Biodegradable Can transport hydrophobic and hydrophilic molecules	Moderate loading capacity Could crystallize after prolonged storage conditions	[152,153]
Polymeric	Biodegradable properties Good tissue penetration Ease manipulation	Non-degradable polymers tend to accumulate in tissues Promote allergic reactions In vivo metabolism and elimination routes are not elucidated	[154]
Biological nanoparticles *
Exosomes	Reduced immune response Protection of circulating genetic material Possibility of cell targeting	Limited transfection efficiency	[155]

* Viruses were not included since they are out of the scope of the review.