Molecular Perspective Mechanism for Drug Loading on Carbon Nanotube-Dendrimer: A Coarse-Grained Molecular Dynamics Study

The loading mechanism of the protein ubiquitin and the drug pyrene, as a representatives of large and small molecules, onto the drug carrier carbon nanotube-polyamidoamine (PAMAM) was studied by using coarse grained molecular dynamics simulation. The results indicated that the optimum and stable drug delivery system for protein loading can be obtained by inserting the molecules in the sequence of: (i) PAMAM, (ii) protein, and (iii) PAMAM. Also, it was found that properly adjusting the weight ratio of PAMAM to the protein, defined as M-WPAMAM/M-WPROTEIN (where M-W is the molecular weight) can lead to achieve a stable system for loading the protein. However, for pyrene loading, it was found that the insertion sequence has no significant effect and only encapsulation of the pyrene molecules into PAMAM and adjustment of the weight ratio of PAMAM to pyrene M-WPAMAM/M-wpyrene) can affect the stability of the drug delivery system.