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

Abstract

Target delivery of large foreign materials to cells requires transient permeabilization of the cell membrane without toxicity. Giant unilamellar vesicles (GUVs) mimic the phospholipid bilayer of the cell membrane and are also useful drug delivery vehicles. Controlled increase of the permeability of GUVs is a delicate balance between sufficient perturbation for the delivery of the GUV contents and damage to the vesicles. Here we show that photoacoustic waves can promote the release of FITC-dextran or GFP from GUVs without damage. Real-time interferometric imaging offers the first movies of photoacoustic wave propagation and interaction with GUVs. The photoacoustic waves are seen as mostly compressive half-cycle pulses with peak pressures of ~ 1 MPa and spatial extent FWHM ~ 36 µm. At a repetition rate of 10 Hz, they enable the release of 25% of the FITC-dextran content of GUVs in 15 min. Such photoacoustic waves may enable non-invasive targeted release of GUVs and cell transfection over large volumes of tissues in just a few minutes.

Ultrasonic photoacoustic emitter of graphene-nanocomposites film on a flexible substrate

“…In principle, shaping the PA lens with a shorter focal distance could reduce the exposed area and lead to a more localized pressure field and cavitation as well. Further, high-frequency ultrasounds and cavitation play an important role in the transdermal drug delivery [58] , [59] , permeabilization of the cell membrane [60] , and release from drug-loaded nanoparticles [17] . Sonophoresis devices usually employ low-frequency (hundreds of kHz) and high-frequency ultrasound (1–16 MHz), depending on the application, that facilitate the transport through the epidermis, stratum corneum, of therapeutic agents.…”

Efficient dermal delivery of ascorbic acid 2‐glucoside with photoacoustic waves

“…The laser tip was inserted in the suitable holder [Colour figure can be viewed at wileyonlinelibrary.com] ultrasound pulses was performed by a 225 MHz Contact High-Frequency Ultrasound Transducer (Olympus) and a 0.075 mm Needle Hydrophone (Precision Acoustics), respectively. The achieved photoacoustic ultrasound pulses presented a broadband spectrum which typically reaches frequencies >100 MHz (Figure 1a) and temporal profile characterized by a very short high-amplitude compressive pulse (~30 ns) followed by lower rarefaction amplitude pulse (Figure 1b) [29].…”

“…These waves have been shown to transiently perturb the stratum corneum promoting skin permeation of molecules from a formulation [26][27][28]. A PA wave is generated when a thin but opaque film absorbs the optical energy of short laser pulses (≤ 20 ns), rapidly converting this energy into heat, and produces a thermoelastic expansion that launches an ultrasound pulse [26,28,29]. Such "piezophotonic" films act as light-topressure transducers, converting light pulses into acoustic waves [26].…”

Photodynamic Therapy Changes Tumour Immunogenicity and Promotes Immune-Checkpoint Blockade Response, Especially When Combined with Enhanced Tumour Infiltration by Micromechanical Priming

“…The increased response to PDT after exposure to photoacoustic waves can be assigned to TME remodelling by 6,000 pressure pulses of ~ 60 bar peak compressional pressures. Safe and transient permeabilization of biological barriers with such pressure pulses has been demonstrated and assigned to pressure gradients of 5 bar/ µm that exert strong mechanical forces at the cellular level (50,51). Such micromechanical forces facilitate tumour in ltration, effectively priming the TME.…”

“…Photoacoustic waves with mostly compressive broadband pressure peaks of ~ 60 bar were generated by the absorption of 8 nsec laser pulses (M-NANO Nd:YAG Montfort Laser) by light-to-pressure transducers made of carbon nanoparticles and polydimethylsiloxane (LaserLeap Technologies, Portugal) (60), using ~ 60 mJ/cm 2 laser uences. Such pressure pulses are known to permeabilize biological barriers (50,51). A layer of acoustic coupling was placed over the epilated tumour, the light-to-pressure transducer was pressed against the gel and the tumour was exposed to photoacoustic waves for 5 min at 20 Hz.…”