Chemical lysis of cyanobacteria.

We have developed a mixture of enzymes and chemicals that completely lyse cyanobacteria. Since the treatment involves only readily-available chemicals and simple proteins that degrade the components of the cyanobacterial cell wall, it can easily be used in high-throughput applications requiring lysis for subsequent intracellular measurements. Our lysis technique consistently enables complete lysis of several different cyanobacterial strains, and we demonstrated that DNA, mRNA, and proteins are preserved in the lysates.

Hybrid pore formation by directed insertion of α-haemolysin into solid-state nanopores.

Most experiments on nanopores have concentrated on the pore-forming protein α-haemolysin (αHL) and on artificial pores in solid-state membranes. While biological pores offer an atomically precise structure and the potential for genetic engineering, solid-state nanopores offer durability, size and shape control, and are also better suited for integration into wafer-scale devices. However, each system has significant limitations: αHL is difficult to integrate because it relies on delicate lipid bilayers for mechanical support, and the fabrication of solid-state nanopores with precise dimensions remains challenging.

Nucleotide identification and orientation discrimination of DNA homopolymers immobilized in a protein nanopore.

Nanopores have been used as extremely sensitive resistive pulse sensors to detect analytes at the molecular level. There has been interest in using such a scheme to rapidly and inexpensively sequence single molecules of DNA. To establish reference current levels for adenine, cytosine, and thymine nucleotides, we measured the blockage currents following immobilization of single-stranded DNA polyadenine, polycytosine, and polythymine within a protein nanopore in chemical orientations in which either the 3' or the 5' end enters the pore.