title: Microscale Sensing of Oxygen via Encapsulated Porphyrin Nanofibers: Effect of Indicator and Polymer "Core" Permeability.
abstract: Biomimetic polymer nanofibers integrate sensing capabilities creating utility across many biological and biomedical applications. We created fibers consisting of either a poly(ether sulfone) (PES) or a polysulfone (PSU) core coated by a biocompatible polycaprolactone (PCL) shell to facilitate cell attachment. Oxygen sensitive luminescent probes Pt(II) meso-tetra(pentafluorophenyl)porphine (PtTFPP) or Pd(II) meso-tetra(pentafluorophenyl)porphine (PdTFPP), were incorporated in the core via single-step coaxial electrospinning providing superior sensitivity, high brightness, linear response, and excellent stability. Both PES-PCL and PSU-PCL fibers provide more uniform probe distribution than polydimethylsiloxane (PDMS). PSU-based sensing fibers possessed optimum sensitivity due to their relatively higher oxygen permeability. During exposure to 100% nitrogen and 100% oxygen, PES-PCL fiber displayed an I0/I100 value of 6.7; PSU-PCL exhibited a value of 8.9 with PtTFPP as the indicator. In contrast, PdTFPP-containing fibers possess higher sensitivity due to the long porphyrin lifetime. The corresponding I0/I100 values were 80.6 and 106.7 for the PES-PCL and PSU-PCL matrices, respectively. The response and recovery times were 0.24/0.39 s for PES-PCL and 0.38/0.83 s for PSU-PCL which are 0.12 and 0.11 s faster, respectively, than the Pt-based porphyrin in the same matrices. Paradoxically, lower oxygen permeabilities make these polymers better suited to measuring higher (i. e., ∼20%) oxygen contents than PDMS. Individual fiber sensing was studied by fluorescence spectrometry and at a sub-micrometer scale by total internal reflection fluorescence (TIRF). Specific polymer blends relate polymer composition to the resulting sensor properties. All compositions displayed linear Stern-Volmer plots; sensitivity could be tailored by matrix or the sensing probe selection.
authors: Ruipeng
authors: R
authors: Xue
authors: Chen
authors: C
authors: Ge
authors: Kris
authors: K
authors: Richardson
authors: Andre
authors: A
authors: Palmer
authors: §Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, United States.
authors: Mariano
authors: M
authors: Viapiano
authors: John J
authors: JJ
authors: Lannutti
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D045744:Cell Line, Tumor; D006801:Humans; D007091:Image Processing, Computer-Assisted; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure; D009584:Nitrogen / Q000032:analysis; D010100:Oxygen / Q000032:analysis*; D010539:Permeability; D011091:Polyesters; D011108:Polymers / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013450:Sulfones / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D011091:Polyesters; D011108:Polymers; D011166:Porphyrins; D013450:Sulfones; C016240:polycaprolactone; C010504:polyacrylonitrile; C017662:polysulfone P 1700; C022840:polyether sulfone; D009584:Nitrogen; D010100:Oxygen
keywords: electrospinning; hypoxia; luminescence; oxygen sensor; permeability; polyacrylonitrile