Biocompatibility of a sonicated silk gel for cervical injection during pregnancy: in vivo and in vitro study

Reprod Sci. 2014 Oct;21(10):1266-73. doi: 10.1177/1933719114522551. Epub 2014 Feb 11.


Objective: To evaluate the biocompatibility of silk gel for cervical injection.

Study design: Silk gel was injected into the cervix of pregnant rats on day 13 (n = 11) and harvested at day 17. Histology of silk gel was compared with suture controls. Also, human cervical fibroblasts were cultured on silk gel and tissue culture plastic (TCP) in vitro. Cell viability, proliferation, metabolic activity, gene expression (COL1A1, COL3A1, and COX2), and release of proinflammatory mediators (interleukin [IL] 6 and IL-8) were evaluated.

Results: In vivo, a mild foreign body response was seen surrounding the silk gel and suture controls. In vitro, cervical fibroblasts were viable, metabolically active, and proliferating at 72 hours. Release of IL-6 and IL-8 was similar on silk gel and TCP. Collagen and COX2 gene expression was similar or slightly decreased compared with TCP.

Conclusions: Silk gel was well tolerated in vivo and in vitro, which supports continuing efforts to develop silk gels as an alternative to cervical cerclage.

Keywords: cerclage; cervix; injectable biomaterial; preterm birth; silk.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Intravaginal
  • Animals
  • Biocompatible Materials / administration & dosage*
  • Biocompatible Materials / chemistry
  • Cell Survival / drug effects
  • Cell Survival / physiology
  • Cells, Cultured
  • Cerclage, Cervical / adverse effects
  • Cerclage, Cervical / methods
  • Cervix Uteri / cytology
  • Cervix Uteri / drug effects*
  • Cervix Uteri / physiology
  • Female
  • Humans
  • Pregnancy
  • Rats
  • Silk / administration & dosage*
  • Silk / chemistry
  • Sonication / methods


  • Biocompatible Materials
  • Silk