Laser-induced fluorescence platform

The high sample demands and low-throughput of LC-MS methods have led to the creation of a capillary electrophoresis (CE) platform for ABPP [48]. Proteomes are labeled with a fluorescent probe, digested with trypsin, and enriched with antifluorophore antibody resins. Use of CE coupled with laser-induced fluorescence (LIF) detection to analyze the enriched peptides resulted in far superior resolution to ID SDS-PAGE, particularly for enzymes that share similar molecular masses. Sensitivity limits of 0.05-0.1 pmol/mg proteome, negligible sample requirements (—0.01—0.1 pg proteome), and the ability to perform rapid CE runs in parallel with 96-channel instruments, make CE-based ABPP a potentially powerful technique. One drawback is that the identities of the probe-labeled proteins are not immediately apparent, and correlated LC-MS experiments must be performed to assign protein identities to the peaks on the CE readout. 

For mechanical lysis, nanostructured filter-Uke contractions are employed in microfluidic channels with pressure-driven cell flow. Prinz et al. utilized rapid diffusive mixing to lyse Escherichia coli cells and trap the released chromosome via dielectrophoresis (DEP). Kim et al. developed a microfluidic compact disk platform for mechanical lysis of cells using spherical particles with an efficiency of approximately 65 % however, this method is difficult to be apphed for single-cell analysis. Lee et al. fabricated nanoscale barbs in a microfluidic chip for mechanical cell lysis by shear and frictional forces. Munce et al. reported a device to lyse individual cells by electromechanical shear force at the entrance of 10 mm separation channels. The contents of individual cells were simultaneously injected into parallel channels for electrophoretic separation, which can be recorded by laser-induced fluorescence OLIF) of the labeled cellular contents. The use of individual separation channels for each cell separation eliminated possible cross-contamination from multiple cell separations in a single channel. 

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