Pharmaceutical Research

, Volume 33, Issue 10, pp 2433–2444

Comparative Study of Poly (ε-Caprolactone) and Poly(Lactic-co-Glycolic Acid) -Based Nanofiber Scaffolds for pH-Sensing

  • Wenjun Di
  • Ryan S. Czarny
  • Nathan A. Fletcher
  • Melissa D. Krebs
  • Heather A. Clark
Research Paper

DOI: 10.1007/s11095-016-1987-0

Cite this article as:
Di, W., Czarny, R.S., Fletcher, N.A. et al. Pharm Res (2016) 33: 2433. doi:10.1007/s11095-016-1987-0



This study aims to develop biodegradable and biocompatible polymer-based nanofibers that continuously monitor pH within microenvironments of cultured cells in real-time. In the future, these fibers will provide a scaffold for tissue growth while simultaneously monitoring the extracellular environment.


Sensors to monitor pH were created by directly electrospinning the sensor components within a polymeric matrix. Specifically, the entire fiber structure is composed of the optical equivalent of an electrode, a pH-sensitive fluorophore, an ionic additive, a plasticizer, and a polymer to impart mechanical stability. The resulting poly(ε-caprolactone) (PCL) and poly(lactic-co-glycolic acid) (PLGA) based sensors were characterized by morphology, dynamic range, reversibility and stability. Since PCL-based nanofibers delivered the most desirable analytical response, this matrix was used for cellular studies.


Electrospun nanofiber scaffolds (NFSs) were created directly out of optode material. The resulting NFS sensors respond to pH changes with a dynamic range centered at 7.8 ± 0.1 and 9.6 ± 0.2, for PCL and PLGA respectively. NFSs exhibited multiple cycles of reversibility with a lifetime of at least 15 days with preservation of response characteristics. By comparing the two NFSs, we found PCL-NFSs are more suitable for pH sensing due to their dynamic range and superior reversibility.


The proposed sensing platform successfully exhibits a response to pH and compatibility with cultured cells. NSFs will be a useful tool for creating 3D cellular scaffolds that can monitor the cellular environment with applications in fields such as drug discovery and tissue engineering.


electrospinning nanofibers pH detection poly(lactic-co-glycolic acid) poly(ε-caprolactone) 



Chromoionophore II




Sodium tetrakis(3,5-bis(trifluoromethyl)phenyl]borate)


Poly(ε-caprolactone) electrospun nanofiber scaffold


Poly(lactic-co-glycolic acid) electrospun nanofiber scaffold



Supplementary material

11095_2016_1987_MOESM1_ESM.pdf (440 kb)
ESM 1(PDF 439 kb)

Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  • Wenjun Di
    • 1
  • Ryan S. Czarny
    • 2
  • Nathan A. Fletcher
    • 2
  • Melissa D. Krebs
    • 2
  • Heather A. Clark
    • 1
  1. 1.Department of Pharmaceutical SciencesNortheastern UniversityBostonUSA
  2. 2.Chemical and Biological EngineeringColorado School of MinesGoldenUSA

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