Biophysical Response to Pulsed Laser Microbeam‐Induced Cell Lysis and Molecular Delivery

Authors:
Open Access
Publisher website
Google Scholar
Abstract
Cell lysis and molecular delivery in confluent monolayers of PtK2 cells are achieved by the delivery of 6 ns, λ = 532 nm laser pulses via a 40×, 0.8 NA microscope objective. With increasing distance from the point of laser focus we find regions of (a) immediate cell lysis; (b) necrotic cells that detach during the fluorescence assays; (c) permeabilized cells sufficient to facilitate the uptake of small (3 kDa) FITC‐conjugated Dextran molecules in viable cells; and (d) unaffected, viable cells. The spatial extent of cell lysis, cell detachment, and molecular delivery increased with laser pulse energy. Hydrodynamic analysis from time‐resolved imaging studies reveal that the maximum wall shear stress associated with the pulsed laser microbeam‐induced cavitation bubble expansion governs the location and spatial extent of each of these regions independent of laser pulse energy. Specifically, cells exposed to maximum wall shear stresses τw, max > 190 ± 20 kPa are immediately lysed while cells exposed to τw, max > 18 ± 2 kPa are necrotic and subsequently detach. Cells exposed to τw, max in the range 8–18 kPa are viable and successfully optoporated with 3 kDa Dextran molecules. Cells exposed to τw, max < 8 ± 1 kPa remain viable without molecular delivery. These findings provide the first direct correlation between pulsed laser microbeam‐induced shear stresses and subsequent cellular outcome.

This publication has 40 references indexed in Scilit: