Rational Design of Plasmonic Nanoparticles for Enhanced Cavitation and Cell Perforation

Abstract

Metallic nanoparticles are routinely used as nanoscale antenna capable of absorbing and converting photon energy with subwavelength resolution. Many applications, notably in nanomedicine and nanobiotechnology, benefit from the enhanced optical properties of these materials, which can be exploited to image, damage, or destroy targeted cells and subcellular structures with unprecedented precision. Modern inorganic chemistry enables the synthesis of a large library of nanoparticles with an increasing variety of shapes, composition, and optical characteristic. However, identifying and tailoring nanoparticles morphology to specific applications remains challenging and limits the development of efficient nanoplasmonic technologies. In this work, we report a strategy for the rational design of gold plasmonic nanoshells (AuNS) for the efficient ultrafast laser-based nanoscale bubble generation and cell membrane perforation, which constitute one of the most crucial challenges toward the development of effective gene therapy treatments. We design an in silico rational design framework that we use to tune AuNS morphology to simultaneously optimize for the reduction of the cavitation threshold while preserving the particle structural integrity. Our optimization procedure yields optimal AuNS that are slightly detuned compared to their plasmonic resonance conditions with an optical breakdown threshold 30% lower than randomly selected AuNS and 13% lower compared to similarly optimized gold nanoparticles (AuNP). This design strategy is validated using time-resolved bubble spectroscopy, shadowgraphy imaging and electron microscopy that confirm the particle structural integrity and a reduction of 51% of the cavitation threshold relative to optimal AuNP. Rationally designed AuNS are finally used to perforate cancer cells with an efficiency of 61%, using 33% less energy compared to AuNP, which demonstrate that our rational design framework is readily transferable to a cell environment. The methodology developed here thus provides a general strategy for the systematic design of nanoparticles for nanomedical applications and should be broadly applicable to bioimaging and cell nanosurgery.

Light-Guided Surface Plasmonic Bubble Movement via Contact Line De-Pinning by In-Situ Deposited Plasmonic Nanoparticle Heating

“…In the NP-water suspension, the laser thermally excites the suspended NPs at the SPR, which leads to volumetric heating of the volume irradiated by the laser beam [22][23][24][25][26] . The volumetric heating induces a thermo-capillary convective flow as schematically shown in Fig.…”

Fluence Threshold Behaviour on Ablation and Bubble Formation in Pulsed Laser Ablation in Liquids

“…Nonlinear excitation is well characterized, with at hreshold for water in the range of 60 Jcm À2 [23] for conditions comparable to the present ones.B ubble formation is also observed at much lower thresholds for linear excitation in colloids, such as plasmonic nanoparticles. [26][27][28] When at arget is placed behind the focal point, we can observe bubble formation on the target and before the target in the water phase (see videograph in Figure 1a nd sketch in Figure 2, top). If the pulse energy exceeds 9.5 mJ in the tightest focus (67 Jcm À2 ), then random small bubbles appear along the laser path and vanish again within their size-related eigenmodes.…”

The wavelength dependence of gold nanorod‐mediated optical breakdown during infrared ultrashort pulses

“…Recently published experimental data by Lachaine et al. were used to validate the optical breakdown model. Data on bubble formation for a gold nanoshell with a silica core radius of 56 nm and a 15 nm thick gold shell were compared against predictions from the wavelength dependent optical breakdown model.…”

“…The difference in the three orders of magnitude in the ρ th coming from the differences in the plasma density calculation and comparison against experimental data. The value for has been previously used in many numerical models as a general criterion for optical breakdown .…”