Packaging microelectromechanical systems (MEMS) frequently makes up about Eighty Pct of both the price and also the failures of the devices. For biological MEMS with microfluidic channels, packaging demands reliable fluid and electrical connections. This report explains different techniques for improving the fabrication of microfluidic circuits as well as the design of leak-tight, re-usable, multi-functional packaging systems. Different materials are surveyed to discover the suitable microfluidic chip substrate for an all-polymer device. Three unique test site designs allow combinatorial experiments and increase the functionality of 3 proven leak-tight packaging fixtures. Ultimately, the successful deposition of chitosan, a polysaccharide biopolymer which may act as the interface layer between inorganic electrodes and biological components for example proteins and nucleic acids, is shown in a packaged microfluidic environment. This research sets the foundation for future applications in….
Contents: Fabrication and Packaging Optimization for Polymer-Based Microfluidics
Chapter I: Introduction and Motivation
BioMEMS: Tiny Sensors and Actuators
Packaging Microfluidic Networks
Biofunctionalizing Patterned Substrates
Chapter II: Material Selection
Device Substrate Material
Traditional Substrate Materials
Transparent Traditional Substrate Materials
Transparent Experimental Substrate Materials
Polycarbonate
Cellulose
Kapton
Other Options
Electrode Layer Materials
Chromium-Gold
Indium-Tin Oxide
Conducting Polymers
Fluid Flow Layer Materials
SU-8
Polydimethyl Siloxane (PDMS)
Packaging Materials
Chapter III: Microfluidic Chip Design
Combinatorial Microfluidics
Micro-Knife-Edge Channels
Test Concept
Wafer Layout
Initial Proof-of-Concept
Varied Channel Geometry
Varied Channel Size
Varied Edge Size
Gasket Mold Wafer
Six-Fold Symmetric Microchannels
Chapter IV: Microfluidic Chip Fabrication
Wafer Preparation
Electrode Patterning Procedure
SU-8 Fabrication Procedure
Single-Layer SU-8
Double-Layer SU-8
SU-8 Bonding
Potential Problems and Solutions
PDMS Fabrication Procedure
SU-8 Master
PDMS Molding
Demolding and Stacking
Temporary and Permanent Sealing
Potential Problems and Solutions
Fabrication
Results
Combinatorial Microfluidics
Micro-Knife-Edge Channels
Six-Fold Symmetric Channels
Chapter V: Microfluidic Packaging Design
External Fluid Control
“X” Packaging
Square Packaging
Ring Packaging62
Fabrication
Chapter VI: Iterative Results of Packaged Flow
“X” Packaging
Square Packaging with Gasket
Square Packaging with Micro-Knife-Edges and Clamps
“X” Packaging with Micro-Knife-Edges and Clamps
Ring Packaging
Chapter VII: Flow Characterization
Macro-Scale Flow Control and Measurement
Flow Simulation
Chapter VIII: Electrical Characterization
Packaged Electrode Properties
Chapter IX: Surface Biofunctionalization
Chitosan Deposition Procedure
Deposition Results…
Source: University of Maryland