J Korean Soc Magn Reson Med.  2011 Apr;15(1):48-56. 10.13104/jksmrm.2011.15.1.48.

Measurements of T1- and T2-relaxation Time Changes According to the Morphological Characteristics of Gold Nanoparticles (GNPs)

• Jang MY
• Han YH
• Mun CW

• KMID: 2041227
• DOI: http://doi.org/10.13104/jksmrm.2011.15.1.48

Abstract

PURPOSE
The aim of this study is to measure the typical MR variables such as T1- and T2-relaxation times according to morphological characteristics of gold nanoparticles as a preliminary study to perform theragnosis using local heating by gold nanoparticles.
MATERIALS AND METHODS
Two types of gold nanoparticles were used. Spheres were synthesized by various methods and stirring speed. Rods were synthesized by adding various concentrations of sphere nanoparticles. Gold nanoparticles were mixed with 2% agarose gel at 1:1 ratio and then signals were acquired using a 1.5T MRI. For the measurements of T1- and T2-relaxation times, TR and TE were varied, respectively. The results were acquired through T1 and T2 curves based on the intensities of MR image using self-developed software. And Statistical analysis was performed.
RESULTS
T1 times were measured 1.86 sec and 2.08 sec for sphere and rod, respectively. On the other hands, T2 times were measured 57 ms and 35.45 ms for sphere and rod.
CONCLUSION
The changes of the MR variables according to the morphological characteristics of the gold nanoparticles were confirmed. Optimal MR imaging conditions can be obtained by choosing proper TR and TE according to the type of nanoparticles.

Keyword

Theragnosis; Gold nanoparticle; Magnetic resonance imaging (MRI); T1-relaxation time; T2-relaxation time

MeSH Terms

Hand
Heating
Hot Temperature
Nanoparticles
Sepharose
Sepharose

Figure

• 

  Fig. 1 Rod type GNPs produced by adding by different amout of sphere GNPs. (a) 1 ml, (b) 0.5 ml, (c) 0.25 ml, (d) 0.125 ml, (e) 0.08 ml, (f) 0.04 ml

• 

  Fig. 2 Phantom and MR image of gold nanoparticles (a) 2% agarose gel phantom with GNPs (b) MR T2* image of GNPs

• 

  Fig. 3 TEM images of sphere type GNPs (a) Sphere 2 particles in the category of synthesis 2 at 150 rpm. (b) Sphere type 3 particles in synthesis 2 at 300 rpm. (c) Sphere type 5 particles in synthesis 3 at 150 rpm. scale bar = 200 nm. (d) Sphere type 6 particles in synthesis 3 at 450 rpm.

• 

  Fig. 4 TEM images of Rod type GNPs. The amounts of sphere type GNPs added are (a) 1 ml, (b) 0.25 ml, (C) 0.125 ml and (d) 0.08 ml, respectively. Scale bars are shown at the southwest corner on each images with 100 nm size.

• 

  Fig. 5 Results of one-way ANOVA test for the variations of the T1- and T2-relaxation times according to the fabrication conditions of sphere GNPs (a) T1 values, *p<0.05 (b) T2 values, *p<0.05

• 

  Fig. 6 Results of one-way ANOVA test for the variations of the T1- and T2-relaxation times according to the fabrication conditions of rod GNPs. (a) T1 values, p<0.05 (b) T2 values, *p<0.05

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