Microfluidic switchboards with integrated inertial pumps

Abstract

Arrays of H-shape microfluidic channels connecting two different fluidic reservoirs have been built with silicon/SU8 microfabrication technologies utilized in production of thermal inkjet printheads. The fluids are delivered to the channels via slots etched through the silicon wafer. Every H-shape channel comprises four thermal inkjet resistors, one in each of the four legs. The resistors vaporize water and generate drive bubbles that pump the fluids from the bulk reservoirs into and out of the channels. By varying relative frequencies of the four pumps, input fluids can be routed to any part of the network in any proportion. Several fluidic operations including dilution, mixing, dynamic valving, and routing have been demonstrated. Thus, a fully integrated microfluidic switchboard that does not require external sources of mechanical power has been achieved. A matrix formalism to describe flow in complex switchboards has been developed and tested.

Temperature Dependence of Inertial Pumping in Microchannels

“…The optical system utilized to observe moving tracers was described elsewhere. 9 The frame rate of the recording camera was synchronized with the pumps' pulse rate, typically at a 1:1 ratio. Thus, tracers' displacement observed over, say, 200 video frames was the result of 200 consecutive pump pulses.…”

“…Integrated inertial pumps are expected to become key drivers of complex microfluidic chips in the future. 9,14 Temperature variations are often an essential part of the workflows, for example in chip-scale PCR thermocyclers. Our results demonstrate that such system must be designed with care, as pumping rates might vary significantly depending on what part of the workflow the device is executing.…”

Rapid Fabrication of Low-Cost Thermal Bubble-Driven Micro-Pumps

“…Thermal bubble-driven micro-pumps (also known as inertial micro-pumps) are an upcoming actuation technology for moving fluid without the use of external pump sources [ 1 , 2 , 3 , 4 , 5 ]. These devices use a small thin film heater to rapidly boil liquid, creating a vapor bubble that displaces adjacent fluid.…”

One-step selective-wettability modification of PMMA microfluidic devices by using controllable gradient UV irradiation (CGUI)

“…Compared with the inorganic materials, such as silicon and glass, which usually require the photolithography and etching technologies to fabricate the microfluidic networks [1,2], polymer exhibits numerous advantages including the reduced cost, increased mechanical and optical properties, and ease of fabrication. Poly (methyl methacrylate) (PMMA), as a thermoplastic polymer, can be processed by hot embossing [3] and mold injecting [4], making it a commonly-used material for mass production.…”