1 research outputs found
Polypeptide-Grafted Macroporous PolyHIPE by Surface-Initiated <i>N</i>-Carboxyanhydride (NCA) Polymerization as a Platform for Bioconjugation
A new class of functional macroporous monoliths from
polymerized
high internal phase emulsion (polyHIPE) with tunable surface functional
groups was developed by direct polypeptide surface grafting. In the
first step, amino-functional polyHIPEs were obtained by the addition
of 4-vinylbenzyl or 4-vinylbenzylphthalimide to the styrenic emulsion
and thermal radical polymerization. The obtained monoliths present
the expected open-cell morphology and a high surface area. The incorporated
amino group was successfully utilized to initiate the ring-opening
polymerization of benzyl-l-glutamate <i>N</i>-carboxyanhydride
(BLG NCA) and benzyloxycarbonyl-l-lysine (LysÂ(Z)) NCA, which
resulted in a dense homogeneous coating of polypeptides throughout
the internal polyHIPE surfaces as confirmed by SEM and FTIR analysis.
The amount of polypeptide grafted to the polyHIPE surfaces could be
modulated by varying the initial ratio of amino acid NCA to amino-functional
polyHIPE. Subsequent removal of the polypeptide protecting groups
yielded highly functional polyHIPE-<i>g</i>-polyÂ(glutamic
acid) and polyHIPE-<i>g</i>-polyÂ(lysine). Both types of
polypeptide-grafted monoliths responded to pH by changes in their
hydrohilicity. The possibility to use the high density of function
(−COOH or −NH<sub>2</sub>) for secondary reaction was
demonstrated by the successful bioconjugation of enhanced green fluorescent
protein (eGFP) and fluorescein isocyanate (FITC) on the polymer 3D-scaffold
surface. The amount of eGFP and FITC conjugated to the polypeptide-grafted
polyHIPE was significantly higher than to the amino-functional polyHIPE,
signifying the advantage of polypeptide grafting to achieve highly
functional polyHIPEs