Micro Mechanism Research of Photoacoustic Effect Based on Gold Nanocomposites in Multiphysics Field

It is significant to precisely control the size and spacing of gold nanoparticles for enhancing the effect of localized surface plasmon resonance (LSPR) in photothermal (PT) therapy and photoacoustic (PA) imaging. A multi-layer array of gold nanoparticles in the optic-thermal-acoustic field was modeled in this study using numerical simulation methods as a means of quantitatively analyzing the microscale heat transfer parameters and nonlinear enhanced PA/PT effects. High special resolution was achieved by taking isolated gold nanoparticles with radii of 20 nm, 40 nm, and 50 nm as examples by finite element analysis (FEA). The peak value of acoustic pressure was 74 Pa under the excitation of 5 ns pulse laser with a wavelength of 532 nm. Gold nanoarray was packed by nanoparticle with separation spacings of 6 nm,7 nm,8 nm, 15 nm, 20 nm, and 40 nm. The optical and thermoacoustic properties of the nanoarray varied as the assembled density of the gold nanoarray increased. The model also verified that mixing the polydimethylsiloxane (PDMS) with gold nanoparticles improved the efficiency of the thermal transformation of nanoarrays by at least 43.52% and amplified PA pressure by 3 grades. The results showed that high PA generation efficiency could be achieved by rationally constructing the composites of PDMS and gold nanoarray.