Parametric assessment of acoustic output from laser-irradiated nanoparticle volumes

Abstract

A photoacoustic technique is being investigated for application to intracellular drug delivery. Previous work [Chakravarty et al., Nat. Nanotechnol. 5, 607–611 (2010)] has shown that cells immersed in nanoparticle-laden fluid underwent transient permeabilization when exposed to pulsed laser light. It was hypothesized that the stresses leading to cell membrane permeabilization were generated by impulsive pressures resulting from rapid nanoparticle thermal expansion. To assist in the study of the drug delivery technique, for which high uptake and viability rates have been demonstrated, an experimental method was developed for parametric assessment of photoacoustic output in the absence of field-perturbing elastic boundaries. This paper presents calibrated acoustic pressures from laser-irradiated streams, showing the impact of parameters including particle type, host liquid, and spatial distribution of laser energy.