title: X-Ray Excited Luminescence Chemical Imaging of Bacterial Growth on Surfaces Implanted in Tissue.
abstract: A pH sensor film is developed that can be coated on an implant surface and imaged using a combination of X-ray excitation and visible spectroscopy to monitor bacterial infection and treatment of implanted medical devices (IMDs) through tissue. X-ray scintillators in the pH sensor film generate light when an X-ray beam irradiates them. This light first passes through a layer containing pH indicator that alters the spectrum according to pH, then passes through and out of the tissue where it is detected by a spectrometer. A reference region on the film is used to account for spectral distortion from wavelength-dependent absorption and scattering in the tissue. pH images are acquired by moving the sample relative to the X-ray beam and collecting a spectrum at each location, with a spatial resolution limited by the X-ray beam width. Using this X-ray excited luminescence chemical imaging (XELCI) to map pH through ex vivo porcine tissue, a pH drop is detected during normal bacterial growth on the sensor surface, and a restoration of the pH to the bulk value during antibiotic treatment over the course of hours with milli-meter resolution. Overall, XELCI provides a novel approach to noninvasively image surface pH for studying implant infections and treatments.
authors.affiliation: Department of Chemistry, Center for Optical Materials Science and Engineering (COMSET) and Environmental Toxicology Program, Clemson University, Clemson, SC, 29634-0973, USA.
authors.forename: Fenglin
authors.initials: F
authors.lastname: Wang
authors.forename: Yash
authors.initials: Y
authors.lastname: Raval
authors.forename: Tzuen-Rong J
authors.initials: TR
authors.lastname: Tzeng
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Anker
mesh_terms: D001419:Bacteria / Q000254:growth & development*; D002138:Calibration; D006863:Hydrogen-Ion Concentration; D049449:Luminescence; D013499:Surface Properties; D014965:X-Rays
keywords: S. epidermidis; X-ray excited luminescence chemical imaging; sensor films