title: Online multi-channel microfluidic chip-mass spectrometry and its application for quantifying noncovalent protein-protein interactions.
abstract: To establish an automatic and online microfluidic chip-mass spectrometry (chip-MS) system, a device was designed and fabricated for microsampling by a hybrid capillary. The movement of the capillary was programmed by a computer to aspirate samples from different microfluidic channels in the form of microdroplets (typically tens of nanoliters in volume), which were separated by air plugs. The droplets were then directly analyzed by MS via paper spray ionization without any pretreatment. The feasibility and performance were demonstrated by a concentration gradient experiment. Furthermore, after eliminating the effect of nonuniform response factors by an internal standard method, determination of the association constant within a noncovalent protein-protein complex was successfully accomplished with the MS-based titration indicating the versatility and the potential of this novel platform for widespread applications.
authors.affiliation: Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China. jmlin@mail.tsinghua.edu.cn.
authors.forename: Wu
authors.initials: W
authors.lastname: Liu
authors.forename: Qiushui
authors.initials: Q
authors.lastname: Chen
authors.forename: Xuexia
authors.initials: X
authors.lastname: Lin
authors.forename: Jin-Ming
authors.initials: JM
authors.lastname: Lin
mesh_terms: D003208:Concanavalin A / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D009862:Online Systems; D010209:Paper; D054730:Protein Interaction Domains and Motifs; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D003208:Concanavalin A