Discrete Chemical Release From a Microfluidic Chip

Abstract

We demonstrate a discrete chemical release method, capable of delivering picoliter volumes of chemical solutions with 100 µm of spatial resolution and 20 µs of response time. The releasing mechanism is based on the transfer of pulsed liquid plugs through a hydrophobic air chamber. A microfluidic chip consisting of such a releasing array (2 × 10) is designed and fabricated. Numerical simulation and experimental testing are performed to verify the working principle. Advantages of this release-on-demand technology include leakage-free, fast response and versatile control of release profile. This new method could be a key enabling technology for precisely controlled release of biochemicals for modern pharmacological and biological research.[ 2006-0253]Index Terms-Air gap, discrete chemical stimulation, microfluidic chip, picoliter chemical release, pulsed liquid ejection.

Fabrication and mechanical properties of microchambers made of polyelectrolyte multilayers

“…Micropackaging of chemical compounds in small and precisely defined quantities that can be remotely activated in a controlled manner is one of the premier challenges in the development of delivery systems. [1][2][3][4][5][6][7][8][9] Micropackaging functions to preserve the content, prevent premature action and provide the ability to release upon request. A site-specific release-on-demand system enables a high efficiency of drug therapy or biochemical stimulation at a single cell level.…”

“…The first exploits ex-vivo microelectromechanical systems (MEMS) such as micro-pumps, valves or electrochemically dissolving caps which electronically trigger the release of a desired component from an array of micro-reservoirs. [1][2][3][4] Such systems provide precise temporal and spatial control over the release process; however, they require external components like a power supply and piping. The size scale of MEMS is usually in the order of tens of microns and above.…”

High-resolution permanent photoresist laminate TMMF for sealed microfluidic structures in biological applications

“…A common strategy here is the use of adhesives. To ensure biocompatibility, epoxy-based adhesives are mainly recommended [29]. This process is quite sensitive to the thickness of the applied adhesive layer.…”

Chemical Stimulation of Adherent Cells by Localized Application of Acetylcholine from a Microfluidic System

“…During a stimulation experiment, the cell culture vessel is mounted above an inkjet printhead with a bubble jet actuator allowing for the application of droplets ( V droplet  = 20 pL) to the bottom face of the membrane. The distance between the inkjet apertures and the membrane was 2–3 mm, providing for an air space (Hu et al, 2007; Zibek et al, 2007) which effectively prevents any leakage of the stimulant from the printhead into the cell culture vessel. The printhead chip (Olivetti), comprising 208 nozzles and multiplexing electronics was integrated into a homemade electronics board and operated using a digital I/O board (National Instruments) controlled by a LabView ® application.…”