Year: 2012
Type: article
Abstract: Optical tweezers allow for manipulating micron-sized objects using pN level optical forces.In this work, we use an optical trapping setup to aid in three separate experiments, all related to the physics of the cellular membrane.In the first experiment, in conjunction with Brian Henslee, we use optical tweezers to allow for precise positioning and control of cells in suspension to evaluate the cell size dependence of electroporation.Theory predicts that all cells porate at a transmembrane potential V T M of roughly 1 V.The Schwann equation predicts that the transmembrane potential depends linearly on the cell radius r, thus predicting that cells should porate at threshold electric fields that go as 1/r.The threshold field required to induce poration is determined by applying a low voltage pulse to the cell and then applying additional pulses of greater and greater magnitude, checking for poration at each step using propidium iodide dye.We find that, contrary to expectations, cells do not porate at a constant value of the transmembrane potential but at a constant value of the electric field which we find to be 692 V/cm for K562 cells.Delivering precise dosages of nanoparticles into cells is of importance for assessing toxicity of nanoparticles or for genetic research.In the second experiment, we conduct nanoelectroporation-a novel method of applying precise doses of transfection agents to cells-by using optical tweezers in conjunction with a confocal microscope to manipulate cells into contact with 100 nm wide nanochannels.This work was done in collaboration with Pouyan Boukany of Dr. Lee's group.The small cross sectional area of these nano channels means that the electric field within them is extremely large, 60 MV/m, which allows them to electrophoretically drive transfection agents into the cell.We find that nano electropo-
Author: Andrew Morss
Institution: The Ohio State University
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2517533524