Biomedical Engineering Reference
In-Depth Information
Water vapor
bubble
formation
ermal
expansion of
particle
Protein
denaturation
Particle
melting
Particle
vaporization
Plasma
generation
Fragmentation
of particle
Melting
of ice
Au
Au
Au
Au
Au
Au
Au
Au
P
L H20
L Au
S H20
S Au
V Au
P atm
V H20
0
100
1063
2660
T(ºC)
FIGURE 18.7 The responses and accompanied phenomena of GNP heating under laser activation. From left to right, as the laser power increases,
the GNP temperature increases and eventually leads to fragmentation of GNP. (Modified from Pustovalov, V. K., Smetannikov, A. S., and Zharov,
V. P., Laser Physics Letters, 5, 2008.)
As estimated in the previous section, the characteristic time for
thermal relaxation of single cells is sub-millisecond, and tem-
perature elevation is small for CW laser. Thus, a high power
pulsed laser is usually required to induce significant tempera-
ture increase and cell death for single cells. The mechanisms of
cell injury with the presence of GNP under laser irradiation can
be different depending on the localization of GNP within cells
and laser parameters used. Next, the biodistribution of GNPs in
cells, and the thermal and nonthermal injuries (mechanical and
chemical effects) after laser irradiation are reviewed.
18.6.2.1 Cellular GNp Biodistribution
Understanding the interactions of GNPs with cells is necessary to
effectively target contrast agent and therapeutics within the cell.
The size, shape, and surface chemistry of NPs affect the cellular
uptake amount and intracellular pathways, and may eventually lead
TABLE 18.6
Thermodynamic Properties for Gold and Water Phase Changes
Substance Phase Transition Temperature (K) Temperature (°C) Heat of Phase Change/Pressure
Au Melting 1336.15 1063.00 64.5 kJ/kg
Vaporization 2933 2660 1578 kJ/kg
Triple point a 1336 1063 0.025Pa
Critical point b 7400 7127 5300 × 10 5 Pa
H 2 O Melting 273.15 0.00 334 kJ/kg
Vaporization 373.15 100.00 2256 kJ/kg
Triple point 273.16 0.01 0.0061 × 10 5 Pa
Critical point 647 374 220.6 × 10 5 Pa
Note: The melting, vaporization, triple, and critical points are listed with corresponding temperature (in
Kelvin and Celsius) and latent heat. For triple point and critical point, the pressure is listed instead of latent heat.
All the data are taken from NIST standard reference data, the NIST chemistry WebBook (http://webbook.nist.
gov/chemistry/) unless noted.
a The triple point of Au was calculated from thermodynamic relations (http://oregonstate.edu/instruct/
me581/Homework/F08/ME581Hmwk3.html).
b Boboridis et al. (1999)
 
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