3/5/09 12:34 PM

MALDI Microfluidics

The microfluidics project is aimed at developing an interface that allows microfluidic chip devices to be “read” by a mass spectrometer. Microfluidic chips are small devices with systems of micrometer sized channels etched into glass, silicon, or molded in plastic. The channels are enclosed by bonding to a flat substrate. Various microfluidic components have been developed to perform valving, mixing, filtering, electrophoresis, liquid chromatography, polymerase chain reaction and other procedures. Sample transport is typically by electroosmosis and/or electrophoresis. In analogy to electronic integrated circuits, multiple components can be combined to form microscale total analysis systems. The advantages of such devices compared to conventional chemical analysis include low cost, small size, low sample consumption, high sensitivity, and rapid analysis.

Lee, J.; Soper, S. A.; Murray, K. K. A Solid-Phase Bioreactor with Continuous Sample Deposition for Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry. Rapid Commun. Mass Spectrom. 2011, 25, 693–699.

A schematic of different deposition modes using the PMMA microfluidic chip and immobilized trypsin bioreactor: (a) continuous deposition mode and (b) spot deposition mode. The channel measured 40 mm x 200 mm x 50 mm and had an array of 50 mm diameter posts with a 50 mm inter-post spacing.
A schematic of different deposition modes using the PMMA microfluidic chip and immobilized trypsin bioreactor: (a) continuous deposition mode and (b) spot deposition mode. The channel measured 40 mm x 200 mm x 50 mm and had an array of 50 mm diameter posts with a 50 mm inter-post spacing.
(a) Assembled tryptic digestion microfluidic chip; chip components including PMMA substrate and cover slip, inlet and outlet connectors, capillary and stainless steel tubes. The sample solution was electrokinetically infused through the bioreactor and the matrix solution was loaded hydrodynamically with a syringe pump. Coaxial tubes mixed the bioreactor output with a matrix solution for deposition on a MALDI target. (b) Schematic top view of the fluid connection between the micropost bioreactor and the capillary tube interface to the deposition system. Two Pt electrodes were inserted into the sample inlet and the end of the bioreactor to electrokinetically drive the sample through the bioreactor.
(a) Assembled tryptic digestion microfluidic chip; chip components including PMMA substrate and cover slip, inlet and outlet connectors, capillary and stainless steel tubes. The sample solution was electrokinetically infused through the bioreactor and the matrix solution was loaded hydrodynamically with a syringe pump. Coaxial tubes mixed the bioreactor output with a matrix solution for deposition on a MALDI target. (b) Schematic top view of the fluid connection between the micropost bioreactor and the capillary tube interface to the deposition system. Two Pt electrodes were inserted into the sample inlet and the end of the bioreactor to electrokinetically drive the sample through the bioreactor.
JMS Cover
Journal of Mass Spectrometry Microfluidics Tutorial Cover

 

  • Lee, Musyimi, Soper, Murray, Development of an Automated Digestion and Droplet Deposition Microfluidic Chip for MALDI-TOF MS. J. Am. Soc. Mass Spectrom. 2008, 19, 964–972.
    (a) Schematic of the PMMA microfluidic chip. The bioreactor measured 40 mm × 100 µm × 100 µm and the solution of sample and matrix are loaded by syringe pumps. On the end of the bioreactor, coaxial tubes were sealed to mix digests with a matrix solution and to deposit onto a MALDI target plate (b) Assembled tryptic digest microfluidic chip: components including PMMA chip and cover slip, inlet and outlet connectors, capillary and stainless steel tube.
    . (a) Schematic of the PMMA microfluidic chip. The bioreactor measured 40 mm × 100 µm × 100 µm and the solution of sample and matrix are loaded by syringe pumps. On the end of the bioreactor, coaxial tubes were sealed to mix digests with a matrix solution and to deposit onto a MALDI target plate (b) Assembled tryptic digest microfluidic chip: components including PMMA chip and cover slip, inlet and outlet connectors, capillary and stainless steel tube.