am300197m_si_001.pdf (410.81 kB)
Self-Assembled Poly(ethylene glycol)-co-Acrylic Acid Microgels to Inhibit Bacterial Colonization of Synthetic Surfaces
journal contribution
posted on 2012-05-23, 00:00 authored by Qichen Wang, Emel Uzunoglu, Yong Wu, Matthew LiberaWe explored the use of self-assembled microgels to inhibit
the
bacterial colonization of synthetic surfaces both by modulating surface
cell adhesiveness at length scales comparable to bacterial dimensions
(∼1 μm) and by locally storing/releasing an antimicrobial.
Poly(ethylene glycol) [PEG] and poly(ethylene glycol)-co-acrylic acid [PEG-AA] microgels were synthesized by suspension photopolymerization.
Consistent with macroscopic gels, a pH dependence of both zeta potential
and hydrodynamic diameter was observed in AA-containing microgels
but not in pure PEG microgels. The microgels were electrostatically
deposited onto poly(l-lysine) (PLL) primed silicon to form
submonolayer surface coatings. The microgel surface density could
be controlled via the deposition time and the microgel concentration
in the parent suspension. In addition to their intrinsic antifouling
properties, after deposition, the microgels could be loaded with a
cationic antimicrobial peptide (L5) because of favorable electrostatic
interactions. Loading was significantly higher in PEG-AA microgels
than in pure PEG microgels. The modification of PLL-primed Si by unloaded
PEG-AA microgels reduced the short-term (6 h) S. epidermidis surface colonization by a factor of 2, and the degree of inhibition
increased when the average spacing between microgels was reduced.
Postdeposition L5 peptide loading into microgels further reduced bacterial
colonization to the extent that, after 10 h of S. epidermidis culture in tryptic soy broth, the colonization of L5-loaded PEG-AA
microgel-modified Si was comparable to the very small level of colonization
observed on macroscopic PEG gel controls. The fact that these microgels
can be deposited by a nonline-of-sight self-assembly process and hinder
bacterial colonization opens the possibility of modifying the surfaces
of topographically complex biomedical devices and reduces the rate
of biomaterial-associated infection.