PubMed Health⌕ Search

Biomedical subjects

Adrian Lau

Publications and source records attributed to Adrian Lau.

2 recordsLinked to original sources

A single cell electroporation chip.

Increasing the cell membrane's permeability can be accomplished via single cell electroporation. Polar substances that cannot otherwise permeate the plasma membrane (such as dyes, drugs, DNA, proteins, peptides, and amino acids) can thus be introduced into the cell. We developed a polymeric chip that can selectively immobilize and locally electroporate single cells. This easy-to-use chip focuses the electric field, eliminating the need to manipulate electrodes or glass pipettes. Moreover, this device allows parallel single cell electroporation. We demonstrate the effectiveness of our device design by electroporating HeLa cells using low applied voltages (< 1 V). We found the average transmembrane potential required for electroporation of HeLa cells to be 0.51 +/- 0.13 V. Membrane permeation is assessed electrically by measuring characteristic 'jumps' in current that correspond to drops in cell resistance, and microscopically by recording either the escape of cytoplasmic dye Calcein AM or the entrance of Trypan blue stain.

Cell Membrane Permeability↗

Conformational changes in the C terminus of Shaker K+ channel bound to the rat Kvbeta2-subunit.

We studied the structure of the C terminus of the Shaker potassium channel. The 3D structures of the full-length and a C-terminal deletion (Delta C) mutant of Shaker were determined by electron microscopy and single-particle analysis. The difference map between the full-length and the truncated channels clearly shows a compact density, located on the sides of the T1 domain, that corresponds to a large part of the C terminus. We also expressed and purified both WT and Delta C Shaker, assembled with the rat KvBeta2-subunit. By using a difference map between the full-length and truncated Shaker alpha-beta complexes, a conformational change was identified that shifts a large part of the C terminus away from the membrane domain and into close contact with the Beta-subunit. This conformational change, induced by the binding of the KvBeta2-subunit, suggests a possible mechanism for the modulation of the K+ voltage-gated channel function by its Beta-subunit.

Animals↗