Rational evaluation of the utilization of PEG-PEI copolymers for the facilitation of silica nanoparticulate systems in biomedical applications.
OBJECTIVE
Polymer constructs are often applied in nanoparticulate systems to expand their applicability. One such common macromolecular modifier is poly(ethylene imine) - poly(ethylene glycol) copolymers. Despite their quite widespread use, and considering that interaction and stabilization mechanisms when combining a polyelectrolyte with a non-charged polymer are not trivial to pinpoint, these systems are generally poorly characterized in literature. Here, we attempt to provide a solid rationale to utilize PEG-PEI copolymers as surface modifiers and stabilizers/dispersion agents in solid colloidal systems with focus on biomedical applicability.


METHODS
mPEG grafted PEI copolymers with two different grafting densities and 100 nm sized non-porous silica nanoparticles (SiNP) were synthesized. Detailed physico-chemical characterization of all prepared materials was conducted with spectroscopic methods, while the interaction mechanisms between the produced copolymers and SiNP were investigated by calorimetry. The influence of increased PEG grafting ratio on the attained colloidal stability of copolymer functionalized SiNP was studied by multiple light scattering, and its further implications on the biobehavior of SiNP were evaluated.


RESULTS
The interaction mechanism between SiNP and copolymers was concluded to be mainly directed by electrostatics, whereas an influence of PEG grafting density on the adsorption process was also observed. The implications of the surface modifications on the in vitro biobehavior of SiNP were investigated by combining the knowledge obtained by the detailed characterizations with microscopy evaluation under in vitro conditions.
Centre for Functional Materials, Laboratory of Physical Chemistry, Åbo Akademi University, Porthansgatan 3-5, FI-20500 Turku, Finland.
Didem
D
Şen Karaman
Centre for Functional Materials, Laboratory of Physical Chemistry, Åbo Akademi University, Porthansgatan 3-5, FI-20500 Turku, Finland.
Tina
T
Gulin-Sarfraz
Centre for Functional Materials, Laboratory of Physical Chemistry, Åbo Akademi University, Porthansgatan 3-5, FI-20500 Turku, Finland.
Gun
G
Hedström
Centre for Functional Materials, Laboratory of Physical Chemistry, Åbo Akademi University, Porthansgatan 3-5, FI-20500 Turku, Finland.
Alain
A
Duchanoy
Laboratory of Organic Chemistry, Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FI-20500 Turku, Finland.
Patrik
P
Eklund
Centre for Functional Materials, Laboratory of Physical Chemistry, Åbo Akademi University, Porthansgatan 3-5, FI-20500 Turku, Finland. Electronic address: jerosenh@abo.fi.
Jessica M
JM
Rosenholm
D000327:Adsorption; D001692:Biological Transport; D003102:Colloids; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D008027:Light; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000494:pharmacology; D011094:Polyethyleneimine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D012542:Scattering, Radiation; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D013816:Thermodynamics
D003102:Colloids; C544016:poly(ethylene glycol)-co-poly(ethyleneimine); D011092:Polyethylene Glycols; D012822:Silicon Dioxide; D011094:Polyethyleneimine
Biomedical applications; Electrostatic adsorption; PEG-PEI copolymers; Polymer stabilization; Silica nanoparticles