A novel approach based on composites of nanoparticular hydroxyapatite (HA)
and PEC of CHT/phosphorylated CHT, which were co-cultured with rat OB
in vitro, was reported by Li et al. [175]. After implantation of this PEC/HA material
into rabbit femur marrow cavities, a promoted OB adhesion, proliferation, and
differentiation in vitro was obtained (bioactive). Because PEC/HA is also biodegradable, it is claimed to be a promising bone-repair material.
5.3.2 In Vivo Interaction of PEC Particles with Blood
The multicomponent biofluid blood consists, among other components, of proteins
and cells and still represents a challenge for interaction studies with PEC particles.
A comprehensive study on the interaction of complexes of PDMAEMA and
either a crosslinked CHT or poly(2-acrylamido-2-methylpropanesulfonic acid)
(PAMPSNa) with human blood from healthy volunteers was reported by Yancheva
et al. [176]. Thereby, PDMAEMA complexed with CHT no longer caused inherent
cytotoxicity compared with the uncomplexed state, but haemostatic activity was
still present. However, PEC of PDMAEMA/PAMPSNa featured both low cytotoxicity and low haemostatic activity. The degree of PDMAEMA quaternization had
an additional influence on both blood compatibility parameters. In particular, the
authors claimed a higher interaction of samples containing higher quaternized
PDMAEMA with the cell walls of blood cells (both red and white) because of
electrostatic attraction to the anionic compounds of their cell membranes.
6 Summary and Outlook
PEC nanoparticles can be easily prepared by controlled mixing of diluted polycation
and polyanion solutions, which may consist of natural polyelectrolytes. Their size
typically ranges between 20 and 500 nm, and they can have spherical, rod-like, or
toroid shapes and can have a loose gel-like up to compact internal structure.
PEC particles have strong aggregation tendencies, but the formed aggregates
may have sufficient colloidal stability.
The colloidal parameters of size, shape, internal structure, and stability of PEC
nanoparticles can be modulated by PEL concentration, ionic strength, pH, PEL
structure, and molecular weight.
PEC particles already serve as drug, protein, and polynucleotide carriers for
pharmaceutical applications.
Knowledge on the interaction between PEC particles and cells of different
natures is in its beginning. Various examples report nontoxic effects and the
binding or internalization of PEC particles at various types of human cells.
The reviewed sizing, shaping, and compartmentalization capabilities of PEC
particles can be applied to tailor drug delivery and cell uptake properties in response
to clinical requirements.
Sizing, Shaping and Pharmaceutical Applications of Polyelectrolyte Complex. . .
251
and PEC of CHT/phosphorylated CHT, which were co-cultured with rat OB
in vitro, was reported by Li et al. [175]. After implantation of this PEC/HA material
into rabbit femur marrow cavities, a promoted OB adhesion, proliferation, and
differentiation in vitro was obtained (bioactive). Because PEC/HA is also biodegradable, it is claimed to be a promising bone-repair material.
5.3.2 In Vivo Interaction of PEC Particles with Blood
The multicomponent biofluid blood consists, among other components, of proteins
and cells and still represents a challenge for interaction studies with PEC particles.
A comprehensive study on the interaction of complexes of PDMAEMA and
either a crosslinked CHT or poly(2-acrylamido-2-methylpropanesulfonic acid)
(PAMPSNa) with human blood from healthy volunteers was reported by Yancheva
et al. [176]. Thereby, PDMAEMA complexed with CHT no longer caused inherent
cytotoxicity compared with the uncomplexed state, but haemostatic activity was
still present. However, PEC of PDMAEMA/PAMPSNa featured both low cytotoxicity and low haemostatic activity. The degree of PDMAEMA quaternization had
an additional influence on both blood compatibility parameters. In particular, the
authors claimed a higher interaction of samples containing higher quaternized
PDMAEMA with the cell walls of blood cells (both red and white) because of
electrostatic attraction to the anionic compounds of their cell membranes.
6 Summary and Outlook
PEC nanoparticles can be easily prepared by controlled mixing of diluted polycation
and polyanion solutions, which may consist of natural polyelectrolytes. Their size
typically ranges between 20 and 500 nm, and they can have spherical, rod-like, or
toroid shapes and can have a loose gel-like up to compact internal structure.
PEC particles have strong aggregation tendencies, but the formed aggregates
may have sufficient colloidal stability.
The colloidal parameters of size, shape, internal structure, and stability of PEC
nanoparticles can be modulated by PEL concentration, ionic strength, pH, PEL
structure, and molecular weight.
PEC particles already serve as drug, protein, and polynucleotide carriers for
pharmaceutical applications.
Knowledge on the interaction between PEC particles and cells of different
natures is in its beginning. Various examples report nontoxic effects and the
binding or internalization of PEC particles at various types of human cells.
The reviewed sizing, shaping, and compartmentalization capabilities of PEC
particles can be applied to tailor drug delivery and cell uptake properties in response
to clinical requirements.
Sizing, Shaping and Pharmaceutical Applications of Polyelectrolyte Complex. . .
251