Stabilized bilayer lipid membranes for flow‐through experiments

Abstract

This work reports a technique for the stabilization of solventless bilayer lipid membranes (BLMs), and the use of stabilized BLMs as flow detectors. Microporous filters composed of glass fibers, polytetrafluoroethylene (PTFE) and polycarbonate (nominal pore sizes from 1 to 5 pm) can serve as interfaces that separate two solution compartments. The micropores in the filter media can act as supports for formation and stabilization of BLMs. One of the solution compartments is used to cast lipid films on the filters, while a carrier electrolyte solution concurrently flows through the opposing compartment. Optimization of the flow cell design, and the chemical composition and methods for preparation of stabilized BLMs, are described. Lipid membranes composed of mixtures of phosphatidyl choline and phosphatidic acid could respond rapidly to pH alterations of the carrier electrolyte solution. Signals would reproducibly appear within a few seconds following the injection of an electrolyte of different pH than the carrier. Signals took the form of a single ion current transient with magnitude of tens of picoamperes (PA) and a duration of seconds. The mechanism of signal generation is explored by differential scanning calorimetry. The results show that a phase transition within a lipid membrane can be triggered by pH alterations of the electrolyte solution. Stabilized BLMs which provide artificial ion gating events hold prospects for chemical sensing of process streams.

Flow injection monitoring and analysis of mixtures of simazine, atrazine, and propazine using filter‐supported bilayer lipid membranes (BLMs)

“…The process of formation of stabilked BLM for flow injection experiments was described recently [24,251. Lipid solution (1OpL) was added dropwise from a microliter syringe to the water surface in the cylindrical cell near the partition.…”

“…The apparatus for the formation of stabilized BLMs was previously described [24,251. The apparatus consisted of two Plexiglas chambers separated by a Saram-Wrap (PVDC; DowBrands L.P., Indianapolis, IN) partition of a thickness of ca.…”

Biosensors based on bilayer lipid membranes for automated continuous monitoring or rapid screening of environmental pollutants

“…Our techniques to prepare stabilized BLM-based sensing devices include the use of filters (i.e., glass microfiber) to support BLMs for flowthrough experiments [2,13] and preparation of sBLMs supported on metal electrodes (with long-term stability and constant response characteristics) [7,15]. Compounds of great interest that can be determined using techniques developed by our group include substrates of hydrolytic enzymes [2], insecticides [16], triazine herbicides [4,5], inorganic ions [6], and gas pollutants [7][8][9].…”

“…The apparatus used for the formation of stabilized filter-supported BLMs for flow-injection experiments was previously reported in literature [2,13]. This apparatus basically consists of two identical Plexiglas chambers separated by a Saran Wrap (PVDC) partition (Figure 1).…”

DNA Biosensor Based on Self-Assembled Bilayer Lipid Membranes for the Detection of Hydrazines

“…The conductance enhancements of s-BLMs that were observed following the adsorption of ssDNA were due to the increase of negative surface charge density of the membrane, where the charge of the phosphate groups of ssDNA induced an increase of cation concentration in the electrical double layer. The combination of an increased cation concentration and structural changes (i.e., defect sites) within the membrane [29][30][31][32], resulted in a rapid enhancement of cation movement through s-BLMs. Figure 1 shows recordings of responses from s-BLMs (at pH 6.8) for different concentrations of hydrazine.…”