Nanofiber-based paramagnetic probes for rapid, real-time biomedical oximetry.
EPR (electron paramagnetic resonance) based biological oximetry is a powerful tool that accurately and repeatedly measures tissue oxygen levels. In vivo determination of oxygen in tissues is crucial for the diagnosis and treatment of a number of diseases. Here, we report the first successful fabrication and remarkable properties of nanofiber sensors for EPR-oximetry applications. Lithium octa-n-butoxynaphthalocyanine (LiNc- BuO), an excellent paramagnetic oxygen sensor, was successfully encapsulated in 300-500 nm diameter fibers consisting of a core of polydimethylsiloxane (PDMS) and a shell of polycaprolactone (PCL) by electrospinning. This core-shell nanosensor (LiNc-BuO-PDMS-PCL) shows a linear dependence of linewidth versus oxygen partial pressure (pO2). The nanofiber sensors have response and recovery times of 0.35 s and 0.55 s, respectively, these response and recovery times are ~12 times and ~218 times faster than those previously reported for PDMS-LiNc-BuO chip sensors. This greater responsiveness is likely due to the high porosity and excellent oxygen permeability of the nanofibers. Electrospinning of the structurally flexible PDMS enabled the fabrication of fibers having tailored spin densities. Core-shell encapsulation ensures the non-exposure of embedded LiNc-BuO and mitigates potential biocompatibility concerns. In vitro evaluation of the fiber performed under exposure to cultured cells showed that it is both stable and biocompatible. The unique combination of biocompatibility due to the PCL 'shell,' the excellent oxygen transparency of the PDMS core, and the excellent oxygen-sensing properties of LiNc-BuO makes LiNc-BuO-PDMS-PCL platform promising for long-term oximetry and repetitive oxygen measurements in both biological systems and clinical applications.
Department of Physics, The Ohio State University, 191West Woodruff Avenue, Physics Research Building, Columbus, OH, 43210, USA.
Vidya P
VP
Bhallamudi
Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA.
Ruipeng
R
Xue
Department of Physics, The Ohio State University, 191West Woodruff Avenue, Physics Research Building, Columbus, OH, 43210, USA.
Carola M
CM
Purser
Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA.
Kayla F
KF
Presley
Department of Neurosurgery, The Ohio State University, Columbus, OH, 43210, USA.
Yeshavanth K
YK
Banasavadi-Siddegowda
Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA.
Jinwoo
J
Hwang
Department of Neurosurgery, The Ohio State University, Columbus, OH, 43210, USA.
Balveen
B
Kaur
Department of Physics, The Ohio State University, 191West Woodruff Avenue, Physics Research Building, Columbus, OH, 43210, USA.
P Chris
PC
Hammel
Department of Physics, The Ohio State University, 191West Woodruff Avenue, Physics Research Building, Columbus, OH, 43210, USA.
Michael G
MG
Poirier
Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA.
John J
JJ
Lannutti
Department of Physics, The Ohio State University, 191West Woodruff Avenue, Physics Research Building, Columbus, OH, 43210, USA. pandian.6@osu.edu.
Ramasamy P
RP
Pandian
D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D060328:Magnetic Phenomena; D008422:Materials Testing; D057139:Nanofibers / Q000737:chemistry*; D010092:Oximetry / Q000295:instrumentation*; D010100:Oxygen / Q000032:analysis; D011091:Polyesters / Q000737:chemistry; D011166:Porphyrins / Q000737:chemistry; D011312:Pressure; D013997:Time Factors
D004129:Dimethylpolysiloxanes; D011091:Polyesters; D011166:Porphyrins; C487013:lithium octa-n-butoxynaphthalocyanine; C016240:polycaprolactone; C013830:baysilon; D010100:Oxygen
EPR oximetry; Electrospun fiber; Naphthalocyanine; Oxygen sensing; Paramagnetic materials; Spin probe