Three-Layer Flow Membrane System on a Microchip for Investigation of Molecular Transport

Abstract

A stable three-layer flow system, water/organic solvent/water, has been successfully applied for the first time in a microchannel to get rapid transport through an organic liquid membrane. In the continuous laminar flow region, the analyte (methyl red) was rapidly extracted across the microchannel from the donor to the acceptor phase through the organic solvent phase (cyclohexane). Thermal lens microscopy was used to monitor the process. The thickness of the organic phase, sandwiched by the two aqueous phases, was approximately 64 microm, and it was considered as a thin liquid organic membrane. Permeability studies showed the effects of molecular diffusion, layer thickness, and organic solvent-water partition coefficient on the molecular transport. In the microchip, complete equilibration was achieved in several seconds, in contrast to a conventionally used apparatus, where it takes tens of minutes. The thickness of the organic and aqueous boundary layers was defined as equal to the microchannel dimensions, and the organic solvent-water partition coefficient was determined on a microchip using the liquid/liquid extraction system. Experimental data on molecular transport across the organic membrane were in agreement with the calculated permeability based on the three-compartment water/organic solvent/water model. This kind of experiment can be performed only in a microspace, and the system can be considered as a potential biological membrane for future in vitro study of drug transport.

Microfluidic chip-based synthesis of alginate microspheres for encapsulation of immortalized human cells

“…Previously, microfluidic laminar flows have been used to create such chemical gradients and to perform liquid-liquid extractions. [17][18][19] These reported experiments involve combinations of miscible fluids or stratified flows containing an immiscible "membrane" flow. By introducing an unreactive laminar stream into the carrier fluid a diffusion barrier was created, which served to delay the interfacial reaction.…”

Nonlinear interfacial dynamics in stratified multilayer channel flows

“…At the same time, the accurate control and manipulation of multilayer microscale flows has become increasingly popular in modern biomedical and other applications. Examples include techniques for concentrating leukocytes from whole blood samples (see SooHoo & Walker 2009), integrated lab-on-chip systems (see Beebe et al 2002;Figeys & Pinto 2000;Hibara et al 2001;Surmeian et al 2002), and the use of microfluidic devices in food engineering (Skurtys & Aguilera 2008). Potential applications in MEMS (micro-electro-mechanical) devices in the aerospace industry have been suggested, such as microthrusters that can propel small scale spacecrafts and satellites -see (Polsin & Choueiri 2002).…”

Surface Modification of Microchip Input Reservoirs for Pressure-induced Sample Injection into Microreactors

“…This approach could be implemented not only for PCR, but also for similar biochemical reactions, 6 and even for multiple sample microfluidic liquid-liquid extraction, [3][4][5] which requires a pressure-induced flow, and is currently under investigation.…”

“…Those issues are of importance for the simultaneous injection of different samples and reagents on a single chip, [3][4][5][6] especially when the volume is in the microliter range, for example for PCR. 7,8 The present article deals with the geometric optimization of input reservoirs, the adjustment of the surface properties of the injection ports using chemical modification techniques, and application of the microfluidic system to multiple samples loading in PCR microreactors using a single syringe pump.…”