Visualization and dynamic size evaluation of nanoparticles in solution by single optical fiber-illuminated video microscope analysis.
OBJECTIVE
It is hoped that nanoparticles will become ever more useful in the development of nanomedicine. To evaluate the behavior of nanoparticles in solution, we aimed to establish a single optical fiber-illumination method that is easy to integrate with a conventional microscope at low cost.


METHODS
Solutions of gold nanoparticles and carbon nanotubes were analyzed in a single optical fiber-illuminated video microscope and the tracks of Brownian motion of these nanoparticles were traced using video images. Their diffusion coefficient was measured by the mean square displacement of the movement. Using the diffusion coefficient in the Stokes-Einstein equation, the hydrodynamic diameter of the nanoparticles in solution was evaluated.


RESULTS
The visualization of gold nanoparticles clearly in a high signal-to-noise ratio was achieved. The evaluated particle sizes of gold nanoparticles were similar to those obtained by a transmission electron microscope and the aggregation process of the carbon nanotubes following incubation was also observed and similar size estimation of the aggregates was performed.


CONCLUSIONS
The single fiber-illumination method was applicable to visualize nanoparticle movement clearly and to estimate their sizes in solution. This simple method is suitable for the in situ observation of the nanoparticle-binding process to target cells.
Suzuto
Masashi
M
Analytical Molecular Medicine and Devices Laboratory, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
Nakamura
Akitoshi
A
Yamanishi
Yuko
Y
Suzaki
Etsuko
E
Kataoka
Katsuko
K
Masujima
Tsutomu
T
D000465:Algorithms; D001185:Artificial Intelligence; D003102:Colloids / Q000032:analysis / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D018715:Microscopy, Video / Q000295:instrumentation* / Q000379:methods*; D053758:Nanoparticles / Q000648:ultrastructure*; D055100:Optical Fibers; D010316:Particle Size; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation; D012996:Solutions
D003102:Colloids; D012996:Solutions