• Focused Ultrasound and Nano-bubbles can induce the permeability of Neuroblastoma cells
  • Fateme Nasrollahi Boroujeni,1,* Mohamad Taghi Ahmadian,2 Dina Morshedi,3
    1. Bioprocess Engineering Research Group, Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran.
    2. School of Mechanical Engineering, Sharif University of Technology, Azadi Ave, PO 11365-11155, Tehran, Iran
    3. Bioprocess Engineering Research Group, Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran.


  • Introduction: By combining focused ultrasound application with nano-bubble system, we assume to induce the permeability of biological barriers and so, allowing drugs to enter the targeted part of a tissue. This occurs when nano-bubbles exert mechanical stresses on the vessel walls by oscillating. So far, the long ultrasound pulses have been employed regarding some preclinical and clinical cases. The purpose of this study is to optimize in vitro sonoporation through characterization of the effects of nano-bubble on tissue permeabilization rate. After fabrication and characterization of 100 nm lipid nano-bubbles, their effects under therapeutic ultrasound on sonoporation in the cells, utilizing fluorescein isothiocyanate (FITC) dextran (70 kDa) as fluorophore marker are verified.
  • Methods: We applied ultrasound pulses (1 MHz, 10% duty cycle, 2.0 W/cm2 at 100 Hz pulse repetition frequency) onto the cells. Nano-bubbles containing FITC-Dex, as a probe, was administered before application of ultrasound pulses. Cells were extracted after 0, 10 or 20 seconds of the ultrasound treatment to assess the extent of FITC. Triton X-100 (TX100) was used during an experimental period of 30 minutes. The cells underwent irreversible permeabilization of the membrane and structural collapse. The permeability of cell could determine with the aid of the scan methods in spectrofluorometry.
  • Results: Brightfield and fluorescence nanoscopy of sonoporated cells showed obvious internalization of the FITC-dextran. The control sample, which was exposed to nano-bubbles and FITC-dextran without insonation, showed little or no residual FITC-dextran on the cell surfaces. Fluorescence intensity of sonoporated cells was statistically different from those unsonoporated with bubbles at all concentrations, while the fluorescence intensity of cells sonoporated with the bubbles was not statistically different at variant concentrations.
  • Conclusion: The results of this study indicate that nano-bubble concentration does not interact dynamically to affect sonoporation efficiency. With respect to the role of nano-bubbles for sonoporation of suspended cells, the additional control over drug-delivery and improvement in drug-uptake is promising.
  • Keywords: Drug Delivery; Focused Ultrasound; Nanotechnologies.