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Enhancing the Carboxylation Efficiency of Silk Fibroin through the Disruption of Noncovalent Interactions
journal contribution
posted on 2020-05-08, 21:43 authored by Danielle
L. Heichel, Kelly A. BurkeSilk
fibroin is a semicrystalline protein used as a renewable polymer
source and as a biomaterial platform, but existing methods to synthetically
modify fibroin suffer from low efficiencies that can limit the protein’s
utility. This work reports on a mild synthesis that results in a 2-fold
increase in carboxylation through the disruption of noncovalent interactions
during the reaction. Importantly, silk fibroin maintains its ability
to form β-sheets that are critical for tailoring mechanical
and degradation properties, as well as for rendering solid constructs
(e.g., films and scaffolds) insoluble in water. Increasing carboxyl
functionalization affords control over protein charge, which permits
tailoring the loading and release of small molecules using electrostatic
interactions. Disruption of noncovalent interactions during aqueous
carbodiimide coupling also significantly enhances conjugation efficiency
of molecules containing primary amine groups, thus enabling high degrees
of functionalization with biological molecules, such as proteins and
peptides, for biomaterial applications.