Formation of nanopores in suspended lipid bilayers using quantum dots

In this work, nanopores are formed in lipid (DOPC:DOPE) membranes suspended across 150 micron apertures by oligomeric aggregation of 12 nm diameter CdSe quantum dots. The bilayer and quantum dot nanopores are simultaneously characterized by low noise electrical current monitoring and epifluorescence microscopy. Suspended lipid bilayers form high resistance gigaseals (>10 GOhm) that serve as barriers to the migration of charged ions and particles. Oligomeric aggregation of quantum dots is observed on the surface of the suspended lipid bilayer in the presence of charge stabilized quantum dot suspensions, The aggregate forms a nanometer scale pore (∼2 nm in diameter) in the bilayer resulting in non-quantal ion current bursts. Migration of net neutral Rhodamine B dye (1.6 nm molecular diameter) across the bilayer is measured only in the presence of the aggregates. Potential applications for the non-lithographic fabrication of bilayer nanopores include biochemical detection, DNA sequencing, or cellular drug delivery.