Integrated Cantilever-Based Flow Sensors with Tunable Sensitivity for In-Line Monitoring of Flow Fluctuations in Microfluidic Systems

For devices such as bio-/chemical sensors in microfluidic systems, flow fluctuations result in noise in the sensor output. Here, we demonstrate in-line monitoring of flow fluctuations with a cantilever-like sensor integrated in a microfluidic channel. The cantilevers are fabricated in different materials (SU-8 and SiN) and with different thicknesses. The integration of arrays of holes with different hole size and number of holes allows the modification of device sensitivity, theoretical detection limit and measurement range. For an average flow in the microliter range, the cantilever deflection is directly proportional to the flow rate fluctuations in the microfluidic channel. The SiN cantilevers show a detection limit below 1 nL/min and the thinnest SU-8 cantilevers a detection limit below 5 nL/min. Finally, the sensor is applied for in-line monitoring of flow fluctuations generated by external pumps connected to the microfluidic system.

[1]  Zheyao Wang,et al.  A self-bended piezoresistive microcantilever flow sensor for low flow rate measurement , 2010 .

[2]  G. J. Veldhuis,et al.  Nanosieves with microsystem technology for microfiltration applications , 1998 .

[3]  G. Whitesides,et al.  Flexible Methods for Microfluidics , 2001 .

[4]  Nam-Trung Nguyen,et al.  Micromachined flow sensors—a review , 1997, Flow Measurement and Instrumentation.

[5]  Qingping Yang,et al.  DP flow sensor using optical fibre Bragg grating , 2001 .

[6]  Gerald Urban,et al.  High resolution flow characterization in Bio-MEMS , 2002 .

[7]  H. S. Wolff,et al.  iRun: Horizontal and Vertical Shape of a Region-Based Graph Compression , 2022, Sensors.

[8]  B. W. van Oudheusden.  The determination of the effective ambient temperature for thermal flow sensors in a non-isothermal environment , 1999 .

[9]  Anja Boisen,et al.  Optimized plasma-deposited fluorocarbon coating for dry release and passivation of thin SU-8 cantilevers , 2007 .

[10]  Ellis Meng,et al.  Micromachined Thermal Flow Sensors - A Review , 2012, Micromachines.

[11]  K. Mogensen,et al.  Recent developments in detection for microfluidic systems , 2004, Electrophoresis.

[12]  Jianbin Wang,et al.  Electrolytic-Bubble-Based Flow Sensor for Microfluidic Systems , 2007, Journal of Microelectromechanical Systems.

[13]  D. Beebe,et al.  Physics and applications of microfluidics in biology. , 2002, Annual review of biomedical engineering.

[14]  J. Czarske,et al.  Precise micro flow rate measurements by a laser Doppler velocity profile sensor with time division multiplexing , 2010 .

[15]  S C Jakeway,et al.  Miniaturized total analysis systems for biological analysis , 2000, Fresenius' journal of analytical chemistry.

[16]  K. Mayora,et al.  Fabrication of SU-8 free-standing structures embedded in microchannels for microfluidic control , 2007 .

[17]  Wolfgang Kronast,et al.  LPCVD against PECVD for micromechanical applications , 1996 .

[18]  Abraham P Lee,et al.  Microfluidic flow transducer based on the measurement of electrical admittance. , 2004, Lab on a chip.

[19]  Jens Anders Branebjerg,et al.  Microfluidics-a review , 1993 .

[20]  N. D. de Rooij,et al.  A differential pressure liquid flow sensor for flow regulation and dosing systems , 1995, Proceedings IEEE Micro Electro Mechanical Systems. 1995.

[21]  Sung Jin Kim,et al.  Electrokinetic flow meter , 2007 .

[22]  A. Boisen,et al.  Processing of thin SU-8 films , 2008 .

[23]  A. Boisen,et al.  Fabrication of thin SU-8 cantilevers: initial bending, release and time stability , 2010 .

[24]  Jan H. J. Fluitman,et al.  Multi-parameter detection in fluid flows , 1995 .

[25]  Anja Boisen,et al.  Fabrication of a cantilever-based microfluidic flow meter with nL min−1 resolution , 2010 .

[26]  M. Elwenspoek,et al.  Microfiltration membrane sieve with silicon micromachining for industrial and biomedical applications , 1995, Proceedings IEEE Micro Electro Mechanical Systems. 1995.

[27]  S. Radhakrishnan,et al.  Scalable microbeam flowsensors with electronic readout , 2005, Journal of Microelectromechanical Systems.

[28]  Tiansheng Hong,et al.  Novel liquid flow sensor based on differential pressure method. , 2007, The Review of scientific instruments.

[29]  A. Boisen,et al.  Deposition of biopolymer films on micromechanical sensors , 2011 .

[30]  Frank Vollmer,et al.  Microfluidic flow rate detection based on integrated optical fiber cantilever. , 2007, Lab on a chip.

[31]  P. Woias,et al.  A novel flow sensor with high time resolution based on differential pressure principle , 1999, Technical Digest. IEEE International MEMS 99 Conference. Twelfth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.99CH36291).

[32]  Walter Lang,et al.  Thermal flow sensor for liquids and gases based on combinations of two principles , 1999 .

[33]  A. Boisen,et al.  Cantilever-like micromechanical sensors , 2011 .

[34]  M. Packirisamy,et al.  PDMS Microcantilever-Based Flow Sensor Integration for Lab-on-a-Chip , 2013, IEEE Sensors Journal.

[35]  D. Petrak,et al.  Micro-flow metering and viscosity measurement of low viscosity Newtonian fluids using a fibreoptical spatial filter technique , 2009 .