Synthesis of Silk Fibroin–Glycopolypeptide Conjugates and Their Recognition with Lectin

Abstract

Silk fibroin (SF), the natural fibrous protein created by the Bombyx mori silk worm, is being increasingly explored as a biomaterial for tissue engineering due to its excellent mechanical strength, high oxygen/water permeability, and biocompatibility. It is also well known that surface modification of SF with organic ligands such as the extracellular protein binding Arg-Gly-Asp (RGD) peptides help adhesion and proliferation of cells better-a key requirement for it to function as extracellular matrices. In this work, we have conjugated synthetic glycopolypeptides (GPs) that were synthesized by controlled ring-opening polymerization of α-manno-lys N-carboxyanhydrides (NCAs) onto SF by using Cu catalyzed click reaction to synthesize a new hybrid material (SF-GP), which we believe will have both the mechanical properties of native SF and the molecular recognition property of the carbohydrates in the GP. By controlling the amount of GP grafted onto SF, we have made three SF-GP conjugates that differ in their ability to assemble into films. SF-GP conjugates having a very high content of GP formed completely water-soluble brush-like polymer that displayed very high affinity toward the lectin concanavalin-A (Con-A). Films cast from SF-GP conjugates using lower amounts of grafted GP were more stable in water, and the stability can be modulated by varying the amount of GP grafted. The water-insoluble film SF-GP(25) was also found to bind to fluorescently labeled Con-A, as was seen by confocal microscopy. Such SF-GP hybrid films may be useful as mimics of extracellular matrices for tissue engineering.

Incorporation of Exogenous RGD Peptide and Inter-Species Blending as Strategies for Enhancing Human Corneal Limbal Epithelial Cell Growth on Bombyx mori Silk Fibroin Membranes

“…These values join the values reported by others [35,48,49,50,51,52] in a range that is notoriously wide, perhaps reflecting the method variability in preparing the membranes. We are not aware of any value having been reported for APSF.…”

Biopolymer/Glycopolypeptide‐Blended Scaffolds: Synthesis, Characterization and Cellular Interactions

“…The mannose polypeptide was used because d ‐(+)‐glucopyranoside and d ‐(+)‐mannopyranoside residues with free 3‐, 4‐, and 6‐hydroxyl groups are known to bind to the tetrameric protein Con A. Hence, if the carbohydrates within the composite scaffolds are exposed to the surface, they are expected to interact with the carbohydrate binding site of Con A . The scaffolds formed with PPO‐mannose (GLN‐Man and CTS‐Man) were treated with the fluorescently labelled Con A and then imaged using fluorescence microscopy (Figure ).…”

“…We recently reported a strategy to introduce glycoprotein‐mimetic glycopolypeptide onto silk fibroin films, which enhanced the surface activity of the naturally hydrophobic silk fibroin films and supported the growth of L929 cells . However, introduction of galactose/glycopolymers onto the biopolymers requires multi‐step chemical conjugation reactions.…”

“…[23] We recently reported as trategy to introduce glycoproteinmimeticg lycopolypeptideo nto silk fibroin films, which enhanced the surfacea ctivity of the naturally hydrophobic silk fibroin films and supported the growth of L929 cells. [24] However,i ntroductiono fg alactose/glycopolymers onto the biopolymers requires multi-step chemical conjugation reactions. Such complexs yntheses can be avoided if the monomeric or polymeric galactose can be physically incorporated into the natural biopolymer hydrogel.…”

Glycopolymer Functionalization of Engineered Spider Silk Protein‐based Materials for Improved Cell Adhesion

“…Glycopolymer‐functionalized surfaces can bind proteins; glucosamine‐based glycopolymers bind wheat germ agglutinin with an affinity that can be enhanced by the glyco‐cluster effect, and galactose‐based glycopolymers bind lectin RCA 120 . Furthermore, functionalization of chitosan‐based materials with wheat germ agglutinin improved the adhesion and viability of fibroblasts on their surfaces, and functionalization of Bombyx mori silkworm fibroin‐based materials with mannose‐based glycopolymers bound the lectin Concanavalin A, and improved the adhesion of myoblasts (L6 skeletal muscle myoblasts) to their surfaces …”