Multilayered microfluidic probe heads

Microfluidics have emerged as powerful processing and analytical tools. However, as they are usually closed systems, they are difficult to use with large samples and surfaces that cannot pass inside their conduits. Here, we extend our previously reported microfluidic probe (MFP) concept, in which a focused stream of liquid is scanned over a surface, for which heads were fabricated using one Si wafer and a molded poly(dimethylsiloxane) (PDMS) block. The new heads comprise a microfabricated Si lid, a chip for hydrodynamic flow confinement (HFC) and standard ports and fittings. The HFC chip carries the smallest structures needed for focusing the liquid on the surface; the Si lid is bonded to the HFC chip using a polyimide adhesive and has macroscopic vias for bonding standard ports and fittings. These heads are easy to fabricate at high yield, have high-resolution potential and are compatible with a large number of chemicals and solvents. We exemplify this by patterning proteins on a surface, directly developing a resist using a high-pH developer, and producing tapered structures in a resist. This work should foster the adoption of MFPs for processing, patterning and analyzing surfaces under microfluidic conditions.

[1]  G. Whitesides,et al.  Solvent compatibility of poly(dimethylsiloxane)-based microfluidic devices. , 2003, Analytical chemistry.

[2]  G. Whitesides,et al.  Microfabrication inside capillaries using multiphase laminar flow patterning , 1999, Science.

[3]  K. Hingerl,et al.  Fabrication of silicon vertical taper structures using KOH anisotropic etching , 2006 .

[4]  P. Yager,et al.  Biotechnology at low Reynolds numbers. , 1996, Biophysical journal.

[5]  Klavs F Jensen,et al.  Solder-based chip-to-tube and chip-to-chip packaging for microfluidic devices. , 2007, Lab on a chip.

[6]  Tomaso Zambelli,et al.  Nanoscale dispensing in liquid environment of streptavidin on a biotin-functionalized surface using hollow atomic force microscopy probes , 2009 .

[7]  Kit T. Rodolfa,et al.  Nanoscale pipetting for controlled chemistry in small arrayed water droplets using a double-barrel pipet. , 2006, Nano letters.

[8]  S. Quake,et al.  Microfluidics: Fluid physics at the nanoliter scale , 2005 .

[9]  R. Austin,et al.  Hydrodynamic Focusing on a Silicon Chip: Mixing Nanoliters in Microseconds , 1998 .

[10]  Horacio D Espinosa,et al.  A nanofountain probe with Sub-100 nm molecular writing resolution. , 2005, Small.

[11]  Göran Stemme,et al.  A method for tapered deep reactive ion etching using a modified Bosch process , 2007 .

[12]  Liming Ying,et al.  Multicomponent submicron features of biomolecules created by voltage controlled deposition from a nanopipet. , 2003, Journal of the American Chemical Society.

[13]  Brian Derby,et al.  Bioprinting: Inkjet printing proteins and hybrid cell-containing materials and structures , 2008 .

[14]  Liming Ying,et al.  Programmable delivery of DNA through a nanopipet. , 2002, Analytical chemistry.

[15]  T. Dillon,et al.  Fabrication and characterization of three-dimensional silicon tapers. , 2003, Optics express.

[16]  Tomoyuki Yasukawa,et al.  A microfluidic dual capillary probe to collect messenger RNA from adherent cells and spheroids. , 2009, Analytical biochemistry.

[17]  E. Arriaga,et al.  On-column labeling for capillary electrophoretic analysis of individual mitochondria directly sampled from tissue cross sections , 2006, Analytical and bioanalytical chemistry.

[18]  Harry Heinzelmann,et al.  Nanodispenser for attoliter volume deposition using atomic force microscopy probes modified by focused-ion-beam milling , 2004 .

[19]  Liming Ying,et al.  Writing with DNA and protein using a nanopipet for controlled delivery. , 2002, Journal of the American Chemical Society.

[20]  David Juncker,et al.  Multipurpose microfluidic probe , 2005, Nature materials.

[21]  G. Whitesides,et al.  Rapid Prototyping of Microfluidic Systems in Poly(dimethylsiloxane). , 1998, Analytical chemistry.

[22]  M. Qasaimeh,et al.  Design and fabrication of a pdms microfluidic probe and perfusion chamber for microfluidic experiments with organotypic brain slices , 2008 .