A reusable device for electrochemical applications of hydrogel supported black lipid membranes

Abstract

Black lipid membranes (BLMs) are significant in studies of membrane transport, incorporated proteins/ion transporters, and hence in construction of biosensor devices. Although BLMs provide an accepted mimic of cellular membranes, they are inherently fragile. Techniques are developed to stabilize them, such as hydrogel supports. In this paper, we present a reusable device for studies on hydrogel supported (hs) BLMs. These are formed across an ethylene tetrafluoroethylene (ETFE) aperture array supported by the hydrogel, which is during in situ polymerization covalently "sandwiched" between the ETFE substrate and a gold electrode microchip, thus allowing direct electrochemical studies with the integrated working electrodes. Using electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy and contact angle measurements, we demonstrate the optimized chemical modifications of the gold electrode microchips and plasma modification of the ETFE aperture arrays facilitating covalent "sandwiching" of the hydrogel. Both fluorescence microscopy and EIS were used to demonstrate the induced spontaneous thinning of a deposited lipid solution, leading to formation of stabilized hsBLMs on average in 10 min. The determined specific membrane capacitance and resistance were shown to vary in the range 0.31-0.49 μF/cm(2) and 45-65 kΩ cm(2), respectively, corresponding to partially solvent containing BLMs with an average life time of 60-80 min. The characterized hsBLM formation and devised equivalent circuit models lead to a schematic model to illustrate lipid molecule distribution in hydrogel-supported apertures. The functionality of stabilized hsBLMs and detection sensitivity of the platform were verified by monitoring the effect of the ion transporter valinomycin.

Electrode-supported biomimetic membranes: An electrochemical and surface science approach for characterizing biological cell membranes

“…Gold is not toxic and easy to handle. Presently, most electrochemical sensors employ thin gold films printed on a nonconductive support since these electrodes are inexpensive, reusable and disposable [63].…”

Interactions between Aquaporin Proteins and Block Copolymer Matrixes

“…The date also show how the function incorporation values were measured and how M n (which can be quantiied using NMR) is related to M w as PDI = M w / M n . This table does not include the incorporation studies that do not include block copolymerprotein interactions, such as cell-free expression systems [73][74][75], nanopores [76,77], encapsulation in hydrophobic interior [6], hydrogel approaches [78,79], and non-amphiphilic polymers [80]. Due to this restriction on the data, the table showcases the results that were made available by Wolfgang Meier and coworkers implementing PMOXA-PDMS-PMOXA triblock copolymers.…”

Recent Development in Aquaporin (AQP) Membrane Design

“…A later iteration of membrane design examined liquid membrane method with relatively small water flux for Spinach plasma membrane protein 2;1 (SoPIP2;1) proteoliposomes, which was placed between the NF membranes that were capable of providing an AQP fingerprint [14]. Designs such as these [14][15][16][17][18] helped to encourage innovative approaches to membranes and develop membrane-based biosensor projects [19]. In 2010, the hydrogel method created at Aquaporin A/S was introduced.…”