The preparation of regenerated silk fibroin microspheres

Abstract

The objective of the present study is to investigate the possibility of preparing pure protein microspheres from regenerated silk fibroin (RSF). It is found that RSF microspheres, with predictable and controllable sizes ranging from 0.2 to 1.5 mm, can be prepared via mild selfassembling of silk fibroin molecular chains. The merits of this novel method include a rather simple production apparatus and no potentially toxic agents, such as surfactants, initiators, crosslinking agents, etc. The results show that the particle size and size distribution of RSF microspheres are greatly affected by the amount of ethanol additive, the freezing temperature and the concentration of silk fibroin. Finally, the mechanism of RSF microspheres formation is also discussed based on our experimental results.

Silk fibroin microparticles as carriers for delivery of human recombinant BMPs. Physical characterization and drug release

“…The size of particles was significantly smaller in the SEM counterpart images, probably due to the large swelling of the particles in the wet state. This was reported also in a former work (Cao et al, 2007). The small particle size presented a double advantage, first by potentially enhancing the drug availability in the particle surface, and also by providing a surgical material that may be suitable for injectable implantation in bone defects in a slurry form.…”

“…Silk fibroin microparticles were prepared by ethanol precipitation according to the method described by Cao et al (2007), with modifications. A solution of 1% (w/v) silk fibroin in phosphate buffer saline (PBS, pH 7.4) was prepared (5 ml) and filtered with a 0.22 µm PVDF membrane (Rotilab, Germany).…”

“…Silk fibroin has been investigated as a carrier for BMPs in several contributions by Kaplan and colleagues, in form of membranes for healing cranial defects in mice (Karageorgiou et al, 2004), electrospun nanofibers (Li et al, 2006), and scaffolds used for critical size defects in rats (Kirker-Head et al, 2007) and mice (Karageorgiou et al, 2006). Fibroin has been recently described to produce microparticles when precipitated with ethanol at specific fibroin concentrations and freeze temperature (Nam and Park, 2001;Cao et al, 2007;Zhang et al, 2007). Ethanol causes a shift in the random coil structure of fibroin to an insoluble beta-sheet configuration (Nam and Park, 2001).…”

Intestinal anti-inflammatory effects of RGD-functionalized silk fibroin nanoparticles in trinitrobenzenesulfonic acid-induced experimental colitis in rats

“…The values are almost identical to those described previously in the literature. 19,33,41 The FESEM images of the RGD-SFNs show that the silk particles were globular granules, quite homogeneous in size ( Figure 2). As can be seen in the images, no apparent differences in the particle surface were observed, due to the relatively small size of the attached molecules in comparison with the overall size of the nanoparticles.…”

Preparation of cross-linked silk fibroin film by γ-irradiation and their application as supports for human cell culture

“…Regenerated silk-based materials are normally stabilized by the induction of β-sheet formation through the use of solvents 4 or by physical stretching. 5 The microstructure and porosity of these silk based biomaterials, as well as features involved in cell interactions, can be changed by chemical modification, blending with biocompatible polymers, or by exploiting different preparation processes.…”