title: Detection of 100 aM fluorophores using a high-sensitivity on-chip CE system and transient isotachophoresis.
abstract: We present a highly sensitive capillary electrophoresis (CE) assay that combines transient, single-interface on-chip isotachophoresis (ITP) and a laser-induced confocal fluorescence detection setup. We performed experimental parametric studies to show the effects of microscope objective specifications and intensity of excitation laser on optimization of a high-sensitivity on-chip CE detection system. Using the optimized detection system, single-molecule detection of Alexa Fluor 488 was demonstrated, and signal data were validated with autocorrelation analysis. We also demonstrated a separation and detection of 100 aM fluorophores (Alexa Fluor 488 and bodipy) in a fast assay using a high-sensitivity on-chip CE detection system and an ITP/CE protocol with no manual buffer exchange steps. This is, to the knowledge of the authors, the highest electrophoretic separation sensitivity ever reported.
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Byoungsok
authors.initials: B
authors.lastname: Jung
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Zhu
authors.forename: Juan G
authors.initials: JG
authors.lastname: Santiago