Photoacoustic transfection of DNA encoding GFP

Abstract

Photoacoustic transfection consists in the use of photoacoustic waves, generated in the thermoelastic expansion of a confined material absorbing a short pulse of a laser, to produce temporary mechanical deformations of the cell membrane and facilitate the delivery of plasmid DNA into cells. We show that high stress gradients, produced when picosecond laser pulses with a fluence of 100 mJ/cm 2 are absorbed by piezophotonic materials, enable transfection of a plasmid DNA encoding Green Fluorescent Protein (gWizGFP, 3.74 MDa) in COS-7 monkey fibroblast cells with an efficiency of 5% at 20 °C, in 10 minutes. We did not observe significant cytotoxicity under these conditions. Photoacoustic transfection is scalable, affordable, enables nuclear localization and the dosage is easily controlled by the laser parameters.

Laser‐assisted nucleic acid delivery: A systematic review

“…As a result of the greater forces, LISW could potentially harm cells because of physical disruption [65], while photoacoustic waves will be less damaging to the target cells and to adjacent tissues [66]. Silva et al used photoacoustic waves from laser‐induced thermoelastic expansion for 10 minutes, and demonstrated a transfection efficiency of 5%, with 100% of the treated cells remaining viable [45]. In comparison, lipofectamine achieved a transfection rate of 23%, but 45% of the cells died.…”

“…Such waves could be from ultrasound transducers, or from lasers. The latter can generate LISW, as described in 14 studies [15,18,[46][47][48][49][50][51][52][53][54][55][56][57] and photoacoustic waves [45] (Table 2). While the exact mechanism of enhanced nucleic acid transfection by photomechanical waves has not been proven, there are two main concepts, based on whether the wave influences the exogenous nucleic acid, driving this into the cell like a projectile [19,56], or whether the wave affects the cell membrane of the target cell, by making this more porous in a reversible disruption event.…”

“…There is heterogeneity between results from in vitro and animal studies [18,53,54]. Ogura et al reported a 120-fold improvement after LISW group for luciferase plasmid DNA [57], but some cell culture studies showed minor improvements of only 3.8% to 5% after LISW [45,46,56]. Terakawa et al showed a 16% enhancement for transfection of lipofectamine [53,54].…”

Imaging of photoacoustic-mediated permeabilization of giant unilamellar vesicles (GUVs)

“…Controlling the permeability of GUVs by non-contact physical processes allows for non-invasive loading and unloading of macromolecules, and has far-reaching implications in diverse fields such as drug delivery 9 , gene transfection 10 , and synthetic biology 11 . Recent efforts to control the permeability of GUVs have focused on ultrasound 12 , 13 , alternating magnetic fields 14 , electropulsation 15 , 16 , and gigahertz acoustic streaming 17 , which are methods that only produce a perturbation when they are turned on, as opposed to chemical methods that change the composition of the organism.…”

“…Recently, generation of broadband, high-intensity photoacoustic waves by the thermoelastic effect has been demonstrated in biocompatible materials which, when excited by short laser pulses (duration τ L < 10 ns) at moderate laser fluences ( E L < 100 mJ/cm 2 ) launch planar ultrasound pulses with peak pressures p max > 5 MPa 18 . These “piezophotonic biomaterials” (light-to-pressure transducers) offer new opportunities for the permeabilization of phospholipid bilayer membranes 10 , 19 .…”