Enhanced gene delivery efficiency in resonant acoustic fields

The potential of resonant acoustic fields (RAF) to facilitate DNA delivery was explored in this study. We reasoned that, driven by the primary acoustic radiation force, suspended cells agglomerated on the pressure nodal planes first and formed cell bands. Nanometer-sized DNA vectors, circulated between nodal planes by acoustic microstreaming, then used the pre-formed cell bands as the nucleating sites to attach on. As a result, the encounter opportunity between DNA vectors and target cells was increased and further enhanced the gene delivery efficiency. In this talk, delivery efficacy of DNA ferried by retroviral or nonviral vector was examined applying RAF. For the viral vector part, our results showed that mega-hertz RAF brought K562 erythroleukemia cells (10⁶ cells/mL) and vesicular stomatitis virus G protein (VSV-G) pseudotyped retroviruses (titer of 5×10⁶ CFU/mL) into close contact at the pressure nodal planes, yielding a 4-fold increment of eGFP transgene expression after 5-min RAF exposure in the presence of 8 μg/mL Polybrene. Furthermore, with a fixed titer of retrovirus, the transduction rate was augmented with the increase of cell concentration. For the nonviral vector part, to avoid electrostatic repulsion and facilitate binding to cell surface, eGFP-encoding DNA plasmids (2 μg/mL) were complexed with polycationic polyethylenimine (PEI) prior to mixing with K562 cells (10⁶ cells/mL) in an acoustic chamber. After 5-min of RAF exposure, our results showed that PEI/DNA complexes were brought into close contact with K562 cells at the pressure nodal planes, and yielding a 10-fold increment of eGFP transgene expression.