Biomedical Engineering Reference
In-Depth Information
biocompatibility while simultaneously taking advantage of the mechanical and
structural properties of the natural or synthetic polymer scaffold. Natural
polymers possess highly ordered and complex quaternary structures that have
excellent aqueous solubility,
in vivo
compatibility and controlled degradation,
and break down into natural amino acids that can be metabolized in the host with
minimal immune response and cytotoxicity. Thus, peptide conjugated natural
polymers can offer a complex yet highly biocompatible platform that also has
biofunctional sequences to direct cell response and tissue function. Peptides can
also be grafted onto synthetic polymers and though they cannot provide the level
of complexity that natural polymers can, synthetic polymers offer better
availability, stability, chemical control and innateness in the host. Synthetic
polymers are readily available at often lower cost than natural polymers and offer
practicality as well as control over the physicochemical properties including
chain length, functional groups, degree of crosslinking, chain architecture, and
subsequently the elasticity, tensile strength and rheological properties and others.
In addition, polymers such as polyethylene glycol have been established as a
nonfouling polymer that resists nonspecific protein adsorption, and polymers
such as polydimethoxysilane do not support bacterial growth [21]. Depending on
the targeted tissue, the polymer can be tailored to provide the structural template
close to the tissue site, and by conjugating critically active portions of the
naturally derived material to synthetic polymers, specific signaling from the
natural material and the inertness of the synthetic material can be combined to
yield a controlled biomaterial with predictable and desired host response.
O
Br
NaH
O
-
O-PEG-O
-
HO-PEG-OH
THF
THF
O
-
OH
O
O
O
O-PEG-O
O-PEG-O
HO
OH
O
O
H
2
O
OH
N
O
O
O
O
O
O
H
2
N-peptide-CO
O
H
O-PEG-O
N
O
O
N
DMF/MES
N C N
O
O
O
O
peptide-COOH
peptide-COOH
O-PEG-O
H
N
Fig. 5. Schematic of peptide conjugation onto polyethylene glycol by first activating the carboxy
group with DCC and using N-hydroxysuccinimide as a leaving group adapted from [22].
H
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