Controlling silk fibroin microspheres via molecular weight distribution

• Published in: Materials Science & Engineering C Vol. 50; pp. 226 - 233
• Main Authors: Zeng, Dong-Mei, Pan, Jue-Jing, Wang, Qun, Liu, Xin-Fang, Wang, Hui, Zhang, Ke-Qin
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2015
• Subjects: Animals; Bombyx; Borides; Buffer solutions; Drug delivery systems; Fibroins - chemistry; Hydrogen-Ion Concentration; Ionic strength; Lithium; Microscopy, Electron, Scanning; Microspheres; Molecular Weight; Osmolar Concentration; Particle Size; Phosphates - chemistry; Polydispersity; Potassium Compounds - chemistry; Salting out; Silk fibroin; Solutions; Spectroscopy, Fourier Transform Infrared; Static Electricity; Microspheres; Silk fibroin; Salting out; Ionic strength; Molecular weight
• ISSN: 0928-4931; 1873-0191
• DOI: 10.1016/j.msec.2015.02.005

Silk fibroin (SF) microspheres were produced by salting out SF solution via the addition of potassium phosphate buffer solution (K2HPO4–KH2PO4). The morphology, size and polydispersity of SF microspheres were adjusted by changing the molecular weight (MW) distribution and concentration of SF, as well as the ionic strength and pH of the buffer solution. Changing the conditions under which the SF fiber dissolved in the Lithium Boride (LiBr) solution resulted in altering the MW distribution of SF solution. Under optimal salting-out conditions (ionic strength>0.7M and pH>7) and using a smaller and narrower SF MW distribution, SF microspheres with smoother shapes and more uniform sizes were produced. Meanwhile, the size and polydispersity of the microspheres increased when the SF concentration was increased from 0.25mg/mL to 20mg/mL. The improved SF microspheres, obtained by altering the distribution of molecular weight, have potential in drug and gene delivery applications. •MW distribution was changed by applying different dissolving methods of SF fiber.•Smaller and narrower MW distribution improves the quality of SF microspheres.•Size and polydispersity of microspheres increase as SF concentration increases.•Improved SF microspheres have potential in drug and gene delivery applications.