Comparative Study of Poly (ε-Caprolactone) and Poly(Lactic-co-Glycolic Acid) -Based Nanofiber Scaffolds for pH-Sensing
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.
KEY WORDSelectrospinning nanofibers pH detection poly(lactic-co-glycolic acid) poly(ε-caprolactone)
Poly(ε-caprolactone) electrospun nanofiber scaffold
Poly(lactic-co-glycolic acid) electrospun nanofiber scaffold
ACKNOWLEDGMENTS AND DISCLOSURES
We thank Dr. Guoxin Rong for critical reading of this manuscript. This research is supported by National Institute of Health (NIH) under grant RO1NS081641.
- 2.Hongisto V, Jernstrom S, Fey V, Mpindi JP, Sahlberg KK, Kallioniemi O, et al. High-Throughput 3D Screening Reveals Differences in Drug Sensitivities between Culture Models of JIMT1 Breast Cancer Cells. Plos One. 2013 23;8(10). English.Google Scholar
- 5.Miller WM, Blanch HW, Wilke CR. A kinetic analysis of hybridoma growth and metabolism in batch and continuous suspension culture: Effect of nutrient concentration, dilution rate, and pH (Reprinted from Biotechnology and Bioengineering, vol 32, pg 947-965, 1988). Biotechnol Bioeng. 2000;67(6):853–71. English.CrossRefPubMedGoogle Scholar
- 18.Haugland R. The handbook: a guide to fluorescent probes and labeling technologies: invitrogen corporation; 2005.Google Scholar
- 23.Ruckh TT, Mehta AA, Dubach JM, Clark HA. Polymer-Free Optode Nanosensors for Dynamic, Reversible, and Ratiometric Sodium Imaging in the Physiological Range. Sci Rep-Uk. 2013;3. English.Google Scholar
- 34.Abedalwafa M, Wang FJ, Wang L, Li CJ. Biodegradable poly-epsilon-caprolactone (Pcl) for tissue engineering applications: a review. Rev Adv Mater Sci. 2013;34(2):123–40. English.Google Scholar
- 44.Buranda T, Wu Y, Perez D, Chigaev A, Sklar LA. Real-time partitioning of octadecyl rhodamine B into bead-supported lipid bilayer membranes revealing quantitative differences in saturable binding sites in DOPC and 1:1:1 DOPC/SM/cholesterol membranes. J Phys Chem B. 2010;114(3):1336–49. English.CrossRefPubMedPubMedCentralGoogle Scholar