Chemical modification of Bombyx mori silk fibers with vinyl groups for thiol-ene click chemistry

Xiaoning Zhang,Zhenyu Chen,Guotao Cheng,Carrie Donley,Jianwei Liang,Yuling Liu

doi:10.1186/s13065-019-0630-7

Abstract

Natural Bombyx mori silk fibroin (SF) fibers were modified with 2-methacryloyloxyethyl isocyanate (MOI) first for the introduction of vinyl groups. Then, 1H,1H,2H,2H-perfluorodecanethiol was grafted onto the SF fibers via thiol-ene click chemistry using ultraviolet light. The formations of MOI-modified and PFDT-grafted SF fibers were analyzed using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The morphology of samples was also revealed by a scanning electron microscope. In addition, differential scanning calorimetry results demonstrated that SF fibers did not show significant change in thermal behavior, regardless of the chemical modification. To confirm the cytotoxicity of the prepared SF fibers, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay was performed, and no toxicity was observed with PFDT-grafted SF fibers. The results also showed that PFDT-grafted SF fibers exhibited good antifouling properties when Chlorella vulgaris (C. vulgaris) was selected as a model for algal cells adhesion experiment.

Highlights

Silkworm Bombyx mori can secrete silk, which consists of sericin and silk fibroin
Chemical modification by methacryloyloxyethyl isocyanate (MOI) monomer Silk fibers were chemically modified by MOI monomer in an anhydrous environment
We plotted the weight gain in silk fibroin (SF) fibers modified with MOI monomer against the reaction time at 35 °C

Summary

Introduction

Silkworm Bombyx mori can secrete silk, which consists of sericin and silk fibroin. The two paralleled fibroin fibers are held together with a layer of sericin on their surfaces [1]. Silk is a natural biopolymer and is highly appreciated for its outstanding characteristics, which majorly result from the properties and structures of silk fibroin. Silk fibroin in different forms can interact with biological systems without introducing adverse immunological responses, demonstrating good biocompatibility and biodegradability [2]. Among various forms, the fibroin fibers are endowed with a combination of attractive strength, toughness, and thermal stability that surpasses many synthetic and natural fibers [3]. There is a growing interest in introducing more functionalities into silk fibroin fibers while preserving its advantageous intrinsic properties [3] in order to expand its

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Conclusion