Encapsulation
of peptide and protein-based drugs in polymeric nanoparticles
is one of the fundamental fields in controlled-release drug delivery
systems. The molecular mechanisms of absorption of peptides to the
polymeric nanoparticles are still unknown, and there is no precise
molecular data on the encapsulation process of peptide and protein-based
drugs. Herein, the self-assembly of different polymers and block copolymers
with combinations of the various molecular weight of blocks and the
effects of resultant polymer and copolymer nanomicelles on the stability
of magainin2, an α-helical antimicrobial peptide, were investigated
by means of all-atom molecular dynamics (MD) simulation. The micelle
forming, morphology of micellar aggregations and changes in the first
hydration shell of the micelles during micelles formation were explored
as well. The results showed that the peptide binds to the polymer
and copolymer micelles and never detaches during the MD simulation
time. In general, all polymers and copolymers simultaneously encapsulated
the peptide during micelles formation and had the ability to maintain
the helical structure of the peptide, whereas the first hydration
shell of the peptide remained unchanged. Among the micelles, the polyethylene
glycol (PEG) micelles completely encapsulated magainin2 and, surprisingly,
the NMR structure of the peptide was perfectly kept during the encapsulation
process. The MD results also indicated that the aromatic and basic
residues of the peptide strongly interact with polymers/copolymers
and play important roles in the encapsulation mechanism. This research
will provide a good opportunity in the design of polymer surfaces
for drug delivery applications such as controlled-release peptide
delivery systems.