title: Ambient nanoelectrospray ionization with in-line microdialysis for spatially resolved transient biochemical monitoring within cell culture environments.
abstract: We have developed a new mass spectrometry (MS) based approach for continuous, spatially resolved in vitro biochemical detection and demonstrated its utility in a 3-D cell culture system. Extracellular liquid is passively extracted at a low flow rate (~10 nL/s) through a small bore silica capillary (ID 50 μm); inline microdialysis (MD) removes ions that would interfere with mass spectrometric analysis, and the sample is ionized by nanoelectrospray ionization (nano-ESI) and mass analyzed in a time-of-flight mass spectrometer. The system successfully detects low-volume, low-concentration releases of a small protein (8 μL of 5 μM cytochrome-c, molecular mass ~12 kDa) and exhibits ~1 min temporal resolution. The system also displays sensitivity to probe proximity to the sample release point. Due to the sensitivity of ESI-MS and its ability to simultaneously detect and identify multiple unanticipated biochemicals, this approach shows considerable potential as a biomarker discovery tool.
authors.affiliation: George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Olivero
authors.forename: Michelle
authors.initials: M
authors.lastname: LaPlaca
authors.forename: Peter A
authors.initials: PA
authors.lastname: Kottke
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D045304:Cytochromes c / Q000032:analysis*; D051379:Mice; D017551:Microdialysis; D008970:Molecular Weight; D036103:Nanotechnology; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D045304:Cytochromes c