“…A protein of interest (POI) may be conjugated to ferritin's surface through genetic fusion of the gene encoding the POI to the N-terminal end of ferritin subunits, which are exposed to the protein's outer surface, using established recombinant DNA technologies for subsequent production in a chosen expression system [ 115 ]. From the expression of simple peptides to complex trimers, genetic fusion of POI on ferritin's external surface has had wide applications in the field of vaccine development, including the search for vaccines against influenza [ [116] , [117] , [118] ] Epstein-Barr virus [ 119 ], hepatitis C [ 73 , 120 , 121 ], HIV-1 [ 73 , 122 ], Lyme [ 123 ], RSV [ 124 ], and SARS-CoV-2 [ [125] , [126] , [127] , [128] , [129] , [130] , [131] , [132] , [133] ] which will be discussed in a later section. A pitfall to expressing a protein of interest on ferritin's exterior through genetic fusion, however, is that care must be taken to recombinantly express antigens in a way that does not impair their stability or conformation, nor impair ferritin's inter-subunit interactions during the self-assembly process [ 75 ].…”