Ion channels are important drug targets and unintended drug interactions with ion channels are also of critical importance, requiring the screening of all drug candidates. Conventional high throughput screening processes for soluble proteins are problematic to apply to ion channels because the channels must be incorporated into a lipid bilayer membrane and transport an ionic current to display their functionality. There are currently no high quality, high throughput assays for ion channel drug screening. Recent efforts to increase throughput have resulted in automated patch clamp systems but these are still over two orders of magnitude lower throughput than conventional drug screening technologies, requiring costly instrumentation, cells, and consumables. For existing methods of ion channel screening, there is a gap in information quality, throughput, and cost. An alternative method of ion channel measurement involves reconstituting them in artificial lipid bilayer membranes. In recent research at UCLA led by the PI, a new high-freezing point lipid membrane composition was developed enabling it to be frozen. When frozen, we showed that it was sufficiently robust to withstand shipping, a major breakthrough. These membranes, when packaged in inexpensive chips, have the potential to significantly change the way ion channel screening is done. Our company, Librede Inc., was formed by the UCLA team to further develop and explore the commercial potential of this technology, the first steps of which are proposed here in this Phase I SBIR proposal. Our ultimate goal is to create an inexpensive, disposable chip containing arrays of lipid membranes to enable low cost high throughput screening of ion channels. In the preliminary work at UCLA, the technology was demonstrated with the shipping of small numbers of membranes, with a net yield of 30%. In the proposed work, we will design and fabricate large array chips containing 48 membranes compatible with industry standard 96 well fluid handling robotics and pipetters. With these chips, we aim to demonstrate the viability of the membrane technology over a much larger scale producing over 3000 membranes. To increase their commercial viability, we will also seek to increase the yield by systematically changing the lipid concentration, solvent composition, solution volume, and thawing temperature. Although this space is potentially very large, the membrane arrays will electrically probed in an automated fashion using a custom-built electrical interface and multiplexer. We will use the materials and designs from Phase I to contract with a plastics manufacturer in Phase II to create an inexpensive, injection molded prototype. At that point, we will have demonstrated a chip able to perform industry standard ion channel screens for a significantly lower cost. These membrane array chips have the potential to increase throughput by several orders of magnitude and similarly decrease cost by several orders of magnitude-as a result, transforming the process of ion channel measurement and screening.
Measurement of ion channel interactions with drugs is a key process in drug discovery and drug safety screening. Due to the difficulty in working with ion channels, the existing processes used are slow, laborious, and expensive. Our team has recently developed a platform for ion channel measurement which is much less expensive and much easier to use, based on lipid membranes that can be shipped, a world first. We propose here to develop inexpensive membrane array chips and use them for large scale production, demonstrating the feasibility of this technology for ion channel screening.
| Poulos, Jason L; Jeon, Tae-Joon; Schmidt, Jacob J (2010) Automatable production of shippable bilayer chips by pin tool deposition for an ion channel measurement platform. Biotechnol J 5:511-4 |
