Reversal viral pore gating relies on reversible conformationchanges of capsid structure that generate pores. These pores allowthe diffusion into the viral core of molecules that are entrappedupon the recovery of the native structure. This loading methodis very efficient but is limited to molecules smaller than the poresize. It was estimated that about 900–1000 doxorubicin moleculescould be encapsulated in red clover necrotic mosaic virus. This load-ing density (number of doxorubicin molecule/particle volume) iscomparable to that of Doxil®, an approved liposomal doxorubicinformulation [16,17].In vitro controlled reassembly contemplates viral particle dis-assembling and reassembling in the presence of the material tobe encapsulated. This method has allowed the encapsulation ofmacromolecules (e.g., nucleic acids, proteins, synthetic polymers)[18,19] and gold NPs [20].