Preparation and Characterization of a Novel Hybrid Hydrogel Composed ofBombyx moriFibroin and Poly(N-isopropylacrylamide)

Ting Wang,Ling-Lei Zhang,Xiao-Jia He

doi:10.1155/2013/832710

Abstract

A novel hybrid hydrogel was prepared and investigated based on silkworm silk fibroin and poly(<i >N</i>-isopropylacrylamide) (PNIPAAm). PNIPAAm was introduced to silk fibroin, the resultant composite hydrogel was examined, and freeze-dried SF/PNIPAAm scaffold was analyzed using LB-550 dynamic light scattering particle-size analyzer, circular dichroism (CD), and scanning electron microscopy (SEM). Our results suggested that the hybrid hydrogels owned the porous sponge-like structures, and the gelation time of SF/PNIPAAm hybrids decreased with an increase in temperature and concentration of each polymer. Results of rheological analysis suggested that the rheological property of resultant SF/PNIPAAm gel depended on the concentration combinations as well as the aging time, which elapsed after mixing the two polymers. Results of CD spectra demonstrated that pH showed little influence on the secondary structure of silk fibroin, and significant changes of <svg style="vertical-align:-0.20473pt;width:16.4375px;" id="M1" height="17.9625" version="1.1" viewBox="0 0 16.4375 17.9625" width="16.4375" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,17.65)"><path id="x47" d="M692 302v-28q-45 -6 -54.5 -17t-9.5 -55v-86q0 -62 7 -95q-7 -2 -32 -7.5l-37 -8l-35.5 -7.5t-40.5 -7t-38.5 -4t-40.5 -2q-165 0 -266 93t-101 243q0 84 32 151t86 108t121.5 63t142.5 22q29 0 62.5 -4t52 -7.5t47.5 -10.5t31 -7l15 -156l-28 -6q-17 87 -66.5 121.5
t-128.5 34.5q-117 0 -191 -80.5t-74 -216.5q0 -56 17 -110t49.5 -100.5t87.5 -74.5t124 -28q53 0 87 17q17 9 24.5 23t7.5 43v85q0 54 -15.5 67.5t-89.5 18.5v28h254z" /></g> <g transform="matrix(.012,-0,0,-.012,12.213,9.488)"><path id="x2032" d="M227 744l-123 -338l-31 15l73 368q12 3 41.5 -8t36.5 -20z" /></g> </svg>, <svg style="vertical-align:-0.20473pt;width:19.975px;" id="M2" height="17.9625" version="1.1" viewBox="0 0 19.975 17.9625" width="19.975" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,17.65)"><use xlink:href="#x47"/></g> <g transform="matrix(.012,-0,0,-.012,12.213,9.488)"><use xlink:href="#x2032"/></g><g transform="matrix(.012,-0,0,-.012,15.746,9.488)"><use xlink:href="#x2032"/></g> </svg>, and G* as surrounding increase temperature above the lower critical solution temperature (LCST).

Highlights

Silks can be processed into many forms that suitable for a variety of biomedical and tissue engineering applications
Results for F3P3 was plotted in Figure 9, in which we observe a significant increase of G󸀠, G󸀠󸀠, and G∗ as surrounding temperature increase above the lower critical solution temperature (LCST)
Results of kinetics of this hydrogel showed that the gelation processes of silk fibroin aqueous solution were significantly shorted and the mechanical properties were significantly improved with the increasing concentration of PNIPAAm and silk fibroin

Summary

Introduction

Silks can be processed into many forms that suitable for a variety of biomedical and tissue engineering applications They can be modified by chemical treatment or used in combination with other materials in order to vary the mechanical and surface chemistry properties. Hybrid gel composed of SF and gelatin was prepared through blending two polymers and the resultant hydrogel exhibited response to temperature due to the thermo-responsibility of gelatin [25]. These stimulate the exploration of new mechanisms, such as “physical crosslinking,” which underlie gelation of SF mixtures and alternatives which can gel with SF, especially stimuli-responsive “smart” materials. The possible association between SF and PNIPAAm chains was elucidated by comparing the change in CD spectra

Experimental

Results and Discussion

Conclusion