Tunable photoacoustic efficiency in infrared of gold nanotubes with gel shells

The structure parameters of core-shell nanoparticles to optimize the photoacoustic(PA)efficiency were investigated.The gold nanotube was taken as the example of such nanoparticles.We studied PA effects through numerical simulations based on the finite element method.Gold shells absorb the incident light and transfer heat into the surrounding polydimethylsiloxane(PDMS),where heat distributes exponentially.The more heat contains in the PDMS,the stronger PA signals will result.Therefore,PA signals grow with the thickness of the PDMS nonlinearly.The largest PA signal can be about 6 times of that from naked gold nanotubes.We also found that the optimal PA conversion can be obtained when the surface plasmon resonance matches with the wavelength of incident pulsed laser by adjusting structure parameters of gold nanotubes.This work may be helpful in the design of infrared PA contrast agents.