Plasma Mediated off-Resonance Plasmonic Enhanced Ultrafast Laser-Induced Nanocavitation

Abstract

The generation of nanobubbles around plasmonic nanostructures is an efficient approach for imaging and therapy, especially in the field of cancer research. We show a novel method using infrared femtosecond laser that generates ≈800 nm bubbles around off-resonance gold nanospheres using 200 mJ/cm(2) 45 fs pulses. We present experimental and theoretical work that demonstrate that the nanobubble formation results from the generation of a nanoscale plasma around the particle due to the enhanced near-field rather than from the heating of the particle. Energy absorbed in the nanoplasma is indeed more than 11 times the energy absorbed in the particle. When compared to the usual approach that uses nanosecond laser to induce the extreme heating of in-resonance nanoparticles to initiate bubble formation, our off-resonance femtosecond technique is shown to bring many advantages, including avoiding the particles fragmentation, working in the optical window of biological material and using the deposited energy more efficiently.

Experimental techniques for imaging and measuring transient vapor nanobubbles

“…However, the best rule is to avoid such distorted signals because they may lead to misinterpretation of the bubble parameters. 58 In all three considered cases (single NB, single NB with misaligned probe beam, and multiple NBs), the durations of the bubble-specific signals could be linked to the maximal diameter of the NB (or the largest NB as in Figure 2(b-I)), while their amplitudes differed significantly and, therefore, their use as NB metrics may lead to artifacts. 59 The third method of NB detection employs the pressure waves generated during the bubble expansion and collapse 23,26 ( Figure 1(c)).…”

“…If such absorbance emerges (due to plasma formation or any non-linear modification of the optical properties of the media), the method may characterize an NB incorrectly. 58,59 In another method, the beam is pointed off the detector aperture and produces a low base level at the detector. In this case, only the light scattered by an NB will reach the detector and will increase its output signal, also producing a time-response with a bubble-specific shape.…”

Immobilization of gold nanoparticles on cell culture surfaces for safe and enhanced gold nanoparticle-mediated laser transfection

“…The interactions, which lead to membrane permeabilization, are based on heating of the particle or nanocavitation due to the near-field enhancement. 6,7 The main disadvantage of all techniques is the incubation with the gold nanoparticles. First, it is time-consuming, which limits the high-throughput applicability in routine usage.…”

Laser-induced breakdown of an optically trapped gold nanoparticle for single cell transfection

“…We have shown that the LIB of trapped polystyrene nanoparticles significantly reduced the energy required for cavitation [6,7]. This leads to the permeabilization of cell membranes and transfection of cells in a targeted area in the absence of a lysis zone of cells.Gold nanoparticle clusters have played a key role in this field, through antibody binding and sequestration with subsequent irradiation by nanosecond or femtosecond laser pulses [8][9][10]. A unique interaction of gold nanoparticles with light, known as surface plasmon resonance, can lead to strong absorption of light for heat generation.…”

“…Gold nanoparticle clusters have played a key role in this field, through antibody binding and sequestration with subsequent irradiation by nanosecond or femtosecond laser pulses [8][9][10]. A unique interaction of gold nanoparticles with light, known as surface plasmon resonance, can lead to strong absorption of light for heat generation.…”