4 research outputs found
The Size of Sonoporation Pores on the Cell Membrane
Published in PubMed Central on 01 October 2010Sonoporation uses ultrasound (US) to generate transient non-selective pores on the cell membrane
and has been exploited as a non-viral intracellular drug and gene delivery strategy. The pore size
determines the size of agents that can be delivered into the cytoplasm using the technique. However,
measurements of the dynamic, submicron-scale pores have not been readily available. Electron
microscopy or atomic force microscopy has been used to gauge pore size but such techniques are
intrinsically limited to post US measurements that may not accurately reveal the relevant information.
As previously demonstrated, changes of the transmembrane current (TMC) of a single cell under
voltage clamp can be used for monitoring sonoporation in real time. Because the TMC is related to
the diffusion of ions through the pores on the membrane, it can potentially provide information of
the pore size generated in sonoporation. Using Xenopus laevis oocytes as the model system, the TMC
of single cells under voltage clamp was measured in real time to assess formation of pores on the
membrane in sonoporation. The cells were exposed to US (0.2 s, 0.3 MPa, 1.075 MHz) in the presence
of Definity™ microbubbles. Experiments were designed to obtain the TMC corresponding to a single
pore on the membrane. The size of the pores was estimated from an electro-diffusion model that
relates the TMC with pore size from the ion transport through the pores on the membrane. The mean
radius of single pores was determined to be 110 nm with standard deviation of 40 nm. This study
reports the first results of pore size from the TMC measured using the voltage clamp technique.National Institutes of Health R01CA116592Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/84356/1/nihms119881.pd