5-3.1.4(b). Disadvantages

• Not suitable for tissues with open or cavitated structures.
  
  
• High exposure to low-frequency (<MHz) ultrasounds result in complete cellular death (rupture of the cell). Thus cellular viability must be taken into consideration while employing this technique.

5-3.1.5. Laser induced transfection

• It involves the use of a brief pulse of focused laser beam.
  
  
• In this method, DNA is mixed with the cells present in the culture and then a fine focus of laser beam is passed on the cell surface that forms a small pore sufficient for DNA uptake into the cells. The pore thus formed is transitory and repairs soon.

5-3.1.6. Bead transfection

• Bead transfection combines the principle of physically producing breaks in the cellular membrane using beads.
  
  
• In this method, the adherent cells are incubated for a brief period with glass beads in a solution containing the DNA.
  
  
• The efficiency of this rapid technique depends on:
• Concentration of DNA in a solution.
• Timing of the addition of DNA.
• Size and condition of the beads and the buffers utilized.

Immunoporation is a recently developed transfection process involving the use of new type of beads, Immunofect^TM beads, which can be targeted to make holes in a specific type of cells.