posted on 2016-12-28, 00:00authored byZhicheng Pan, Danxuan Fang, Nijia Song, Yuanqing Song, Mingming Ding, Jiehua Li, Feng Luo, Hong Tan, Qiang Fu
Polymeric
micelles containing cationic gemini quaternary ammonium (GQA) groups
have shown enhanced cellular uptake and efficient drug delivery, while
the incorporation of poly(ethylene glycol) (PEG) corona can potentially
reduce the absorption of cationic carriers by opsonic proteins and
subsequent uptake by mononuclear phagocytic system (MPS). To understand
the interactions of GQA and PEG groups and their effects on the biophysicochemical
characteristics of nanocarriers, a series of polyurethane micelles
containing GQA and different molecular weights of PEG were prepared
and carefully characterized. It was found that the GQA and PEG groups
are unevenly distributed on the micellar surface to form two kinds
of hydrophilic domains. As a result, the particle surface with some
defects cannot be completely shielded by the PEG corona. Despite this,
the longer PEG chains with a brush conformation provide superior stabilization
and steric repulsion against the absorption of proteins and, thus,
can reduce the cytotoxicity, protein absorption, and MPS uptake of
micelles to some extent. This study provides a new understanding on
the interactions between PEG chains and cationic groups and a guideline
for the design and fabrication of safe and effective drug delivery
systems.