CAREER: Bio-Inspired Transport Assays and Single-Molecule Detection using Micro-and Nanopores

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

0449088 Mayer The proposed research will focus on two related, bio-inspired projects. In one project, wells of volumes comparable to living cells (~10 12 liters) will be fabricated in silicon, glass, or polymer substrates. The open side of these microwells will be closed by a biomembrane. The Principal Investigator (PI) will then apply Nature's concept of using small, enclosed volumes to detect the in- or outflux of only a few molecules or ions. Like cells, the proposed setups will use multiple modes of amplification to detect the rapid rise in concentration after influx of less than 10,000 molecules through lipid bilayer membranes. These setups will be ideally suited to follow (i) passive transport of therapeutic drugs through lipid bilayers, (ii) activation of transmembrane receptors such as G protein-coupled receptors, and (iii) ion channel activity. Combining microfluidics with electrical and single-molecule fluorescence measurements might make it possible to (i) elucidate the time delay from binding of a fluorescent ligand to an ion channel to the opening of the pore in these proteins and (ii) investigate clinically relevant transporter proteins on a single molecule level. In the other project, The PI will use nanofabrication by femtosecond-pulsed lasers to take the bio-inspired approach one step further. The biological lipid membrane will be replaced with a robust, synthetic quartz membrane that supports a single nano-machined pore. In analogy to the gating characteristics and specificity of ion channels, the wall of the nanopore will be modified to attain specificity for antibodies, antigens, or viruses. Binding of those biomolecules might gate the current flux through the nanopore and result in more sensitive and diagnostically conclusive clinical assays than standard technology.