Acoustic pressure pulses from laser-irradiated suspensions containing gold nanospheres in water: Experimental and theoretical study

We present a physical model that describes the acoustic pressure pulses from diluted suspensions of metal nanospheres in a liquid medium irradiated by laser pulses. The experimental measurements of the photoacoustic signals are also reported, where the suspensions of 8-nm gold nanospheres in water at different concentrations and different temperatures were irradiated by 0.8-ns laser pulses. We mainly investigate how the nanosphere concentration and the suspension temperature influence the photoacoustic responses. The estimations from our model are found to be in good agreement with the results from the experiments

Effects of Oak Wilt Disease on Fungal Community Composition and Wood Decomposition in Dead Quercus serrata Trunks

departmental bulletin pape

Size-dependent effect of gold nanospheres on the acoustic pressure pulses from laser-irradiated suspensions

We carried out the experimental measurements of photoacoustic responses, where the suspensions of spherical gold nanoparticles (NPs) of different diameters (20, 40, and 50 nm) in water at different concentrations and different temperatures (4 and 20 °C) were irradiated by 0.8-ns laser pulses. In the case of 20 °C, the values of photoacoustic signals normalized by the light absorbance of the NP suspension decreased with increasing the NP size. The photoacoustic signals at 4 °C were significantly reduced compared with those at 20 °C. These experimental results are in fair agreement with the estimations from our phenomenological model, where the acoustic pressure pulse is represented by a sum of two contributions from the NPs and the surrounding liquid medium

Effect of interfacial serum proteins on melanoma cell adhesion to biodegradable poly(L-lactic acid) microspheres coated with hydroxyapatite.

We have measured the interaction forces between a murine melanoma cell and a poly(L-lactic acid) (PLLA) microsphere coated with/without hydroxyapatite (HAp) nanoparticles (i.e., an HAp/PLLA or a bare PLLA microsphere) in a serum-free culture medium, using atomic force microscopy (AFM) with colloid probe technique, in order to investigate how the HAp-nanoparticle coating as well as interfacial serum proteins influence the cell-microsphere adhesion. The cell adhesion force of the HAp/PLLA microspheres was 1.4-fold stronger than that of the bare PLLA microspheres. When the microspheres were pretreated with a culture medium supplemented with 10% fetal bovine serum, the cell adhesion force of the HAp/PLLA microspheres was increased by a factor of 2.1; in contrast, no change was observed in the cell adhesion force of the bare PLLA microspheres before/after the pretreatment. Indeed, the cell adhesion force of the HAp/PLLA was 2.8-fold larger than that of the bare PLLA after the pretreatment. Additionally, we have investigated the effect of interfacial serum proteins on the zeta potentials of these microspheres. On the basis of the obtained results, possible mechanism of cell adhesion to the HAp/PLLA and bare PLLA microspheres in the presence/absence of the interfacial serum proteins is discussed

Acoustic pressure pulses from laser-irradiated suspensions containing gold nanospheres in water: Experimental and theoretical study

We present a physical model that describes the acoustic pressure pulses from diluted suspensions of metal nanospheres in a liquid medium irradiated by laser pulses. The experimental measurements of the photoacoustic signals are also reported, where the suspensions of 8-nm gold nanospheres in water at different concentrations and different temperatures were irradiated by 0.8-ns laser pulses. We mainly investigate how the nanosphere concentration and the suspension temperature influence the photoacoustic responses. The estimations from our model are found to be in good agreement with the results from the experiments