Preparation and Characterization of Fe3O4 Magnetic Nanoparticles Labeled with Technetium-99m Pertectnetate

Chang-Shu Tsai1,2,3,a*, Wei-Chung Liu1,2,3,b, Hong-Yi Chen2,c, Wei-Chun Hsu2,d

1Department of Medical Imaging and Radiological Sciences, No. 880, Sec.2, Chien-kuo Road, Hualien, Taiwan 97005, R. O. C.

2Institute of Radiological Science, No. 880, Sec.2, Chien-kuo Road, Hualien, Taiwan 97005, R. O.C.

3Research Center for Agricultural Biomedicine, Tzu-Chi College of Technology, No. 880, Sec.2, Chien-kuo Road, Hualien, Taiwan 97005, R. O. C.

a*fred@tccn.edu.tw, bliuw@tccn.edu.tw, cktt@tccn.edu.tw, drtp00@tccn.edu.tw

Keywords: Fe3O4 magnetic nano-particles(MNP), dextran, Technetium-99m pertectnetate , labeling efficiency, stability

Abstract. In the aspect of biomedical diagnosis, magnetic nanoparticle can be used as drug carrier

and MRI/ SPECT/ PET contrast agents. Magnetic fluid hyperthermia is one of the most important

cancer therapies. Magnetic nano-particles display their unique features as heating mediators for

hyperthermia. In this study, Fe3O4 magnetic nano-particle was prepared by using chemical

co-precipitation method. Tc-99m pertechnetate with Fe3O4 magnetic nano-particles is prepared by

using magnet adsorption method. An attempt was also made to evaluate the application in the field

of magnetic targeted drug delivery and radioactive targeted cancer treatment in the future. In this

work, preparation and characterization of non-polymer and polymer (dextran)–coated Fe3O4

magnetic nano-particles labeled with technetium-99m pertectnetate were evaluated and served as

precursors study. The Tc-99m labeling efficiency of in-house Fe3O4 magnetic nanoparticles (MNP)

and commercial kit were ca.98.4 % and 85% (n＝5), under the same conc. of 6mM, 0.1 ml of

SnCl2·2H2O, respectively. The Tc-99m labeling efficiency of magnetic nanoparticles with its

dextran-coated was ca. 58.2% (n＝5) at the same conc. and volume of SnCl2·2H2O. The in-vitro

stabilities of the 3 kinds of magnetite magnetic fluids were higher than 96.0% (n＝5) during 2 hours.

The reducing agent of SnCl2·2H2O plays a key role due to its reducing ability for Tc-99m

pertechnetate. The optimal reaction time of SnCl2·2H2O with Tc-99m is better under 1 hour. In

conclusion, the Fe3O4 magnetic nano-particle labeled with Tc-99m pertechnetate has shown good

qualities for its labeling efficiency and stability. It may be feasible preliminary to utilize in the

application of magnetic targeted drug delivery of bio-medicine.

Introduction

In clinic medical application, magnetic targeted drug delivery can lift up the efficiency of

treatment, decrease the adverse reaction and support detection sites by controlling the

bio-distribution of drug in the lesion[1-4]. For example, the Fe3O4 magnetic nano-particles coating

polymethacrylate combined with the novel usefulness of drug, antibody, proteins as drug-carrier

injecting into the human body. According to the animal test, Fe3O4 magnetic nano-particles can

guide the bio-distribution of drug to transfer to the locations of lesion under an external magnet ,

and achieve the goals of treatment, drug release or lesion detection[1-4].

The mainly aim of radioactive targeted drug treatment is to increase the severe damage of tumor

tissue and decrease the damage of normal tissue. The common nuclides with several micro-meters

(µm) range of alpha particles or some mini-meter (mm) range of beta-particles were selected for

treatment purposes. They are I-131, Y-90, Cu-67, Bi-212, Re-188, P-32 and so on. The labeled

radioactive targeted drug can guide the bio-distribution of drug to transfer to the near locations of

lesion under an external magnet [5-9].

Applied Mechanics and Materials Vol. 459 (2014) pp 51-59Online available since 2013/Oct/31 at www.scientific.net© (2014) Trans Tech Publications, Switzerlanddoi:10.4028/www.scientific.net/AMM.459.51

All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP,www.ttp.net. (ID: 132.239.1.230, University of California, San Diego, La Jolla, USA-16/09/14,04:43:20)

In 1999, Goodwin et al. got the image of liver with the 67 % radioactivity of the mixed magnetic

nano-particles with Tc-99m pertechnetate after one hour injection by whole-body gamma camera

[10]. In 2001, Häfeli et al. used the 80% amount of iron powder and 20% amount of active carbon,

and then labeled with the Re-188. The particle size is ca. 0.5~5 micro-meter [11]. Häfeli et al. got

ca. 95% labeling efficiency of magnetic nano-particles with Tc-99m pertechnetate, when choosing

the SnCl2·2H2O as the reductive agent, and increasing the temperature to 99℃.In 2004, Fu et al.

measured the 99 % labeling efficiency of magnetic nano-particles with Tc-99m pertechnetate by

paper chromatography , when using the simply chemical solution method. the reductive agent,

and increasing the temperature to 99℃.The labeling efficiency was still higher than the 90 % after 6

hours[12-13]. The radioactive magnetic nano-particles displayed the fine images in chest and upper

abdomen by live animal test. The partly drug was absorbed under the Nd–Fe–B magnet . It showed

the feasibility that the radioactive magnetic nano-particles can effectively treat the cancer under the

suitable magnet[13]. Radioactive Tc-99m is mainly from the Mo-99-Tc-99m generator. The extreme

usefulness of this generator is due to the excellent radiation characteristics of Tc-99m, namely its

6-hr half, very little electron emission, and a high yield of 140-keV γ- ray(90%), which are nearly

ideal for the current generation of imaging devices in nuclear medicine[14].

The purpose of this study is to investigate the preparation and characterization of Fe3O4

magnetic nano-particles (MNP) and MNP-dextran labeled with technetium-99m

pertechnetate( 99m

TcO4- ). The labeling efficiency and stabilities of Tc-99m with Fe3O4 magnetic

nano-particles (Tc-99m- Fe3O4)and Fe3O4 magnetic nano-particles with dextran-coated (Tc-99m-

dextran -Fe3O4) will be also evaluated.

Materials and methods

Calibration of dose calibrator. The standard source of Cs-137 with 207.2µCi radioactivity of

207.2μCi and Ba-133 with 249.6μCi radioactivity of 249.6µCi (ref.date:2003/03/01) were

selected to calibrate the dose calibrator including linearity, precision and accuracy(n＝10). The dose

calibrator showed the good qualities in this study.

Measuring the labeling efficiency and stability after 2 hrs of Tc-99m pertechnetate with Fe3O4

magnetic nano-particles by using magnet adsorption method [3,15,16,18]. Fe3O4 magnetic

nanoparticle was prepared by using chemical coprecipitation method, and its characterization were

studied thoroughly. In the preparation process, the variety of factors were examined by

time-temperature curve, XRD pattern, SQUID, XPS analysis and FTIR spectroscopy for evaluating

their qualities[15,16].The preparation of Tc-99m pertechnetate with Fe3O4 magnetic nano-particles

by using magnet adsorption method[3, 18].The 50mg/ml of Fe3O4 magnetic nano-particles (MNP)

was heated to powder, and then it was solved in de-ion water, and made samples dispersedly by

ultrasound shaking. One MBq of Na 99m

TcO4 was added to MNP solution, and then 0～6mM of

SnCl2·2H2O was added and used as reducing agent in this study [14]. The labeling efficiency and

stability of Tc-99m pertechnetate (99m

TcO4-) with Fe3O4 magnetic nano-particles were measured

according to the equation as below:

100-[(��(��)���(��)

��(��)]x100% =Labeling efficiency(%),

Ex is the measurement value(MBq) not using magnet adsorption method, Ey is the measurement

value(MBq) by using magnet adsorption method. The simple procedure is as

follows:99m

Tc-MNP→Reaction time→Ex→magnetic decanation→Ey [15,16].

Effect of labeling efficiency of 99m

Tc-MNP solution when using fixed molar concentration , but

different volume of SnCl2.2H2O solution[13,14,18]. The reducing agent of SnCl2·2H2O solution

is a important factor affecting labeling efficiency of 99m

Tc-MNP solution. It were measured for

different volume(0.1-0.7 ml), shelf time(1hr-1month) of SnCl2.2H2O solution at fixed

concentration condition(0.1 mM- 6 mM).

Effect of labeling efficiency of 99m

Tc-MNP solution when using fixed volume ,but different

molar concentration , reaction time of different SnCl2·2H2O solution. The reducing agents of

52 Applied Mechanics and Mechanical Engineering IV

SnCl2·2H2O solution is still a important factor affecting the labeling efficiency of 99m

Tc-MNP

solution [14,18,20]. It were measured for different concentration (0.1 mM～6 mM), shelf time

(1min-1hr) of SnCl2·2H2O solution at fixed volume condition(0.1～0.7 ml).

Effect of labeling efficiency of 99m

Tc-MNP solution for different substances [18]. The Fe3O4

magnetic nano-particles which coating dextran were prepared [13,15-16].The different substances

were chosen as the effecting factors including commercial kit of Fe3O4 magnetic nano-particles,

Fe3O4 magnetic nano-particles coating polymer-dextran. In fact, dextran [(C6H10O5)n , Sigma, MW :

9,000-11,000] is most common and useful surfactant with good bio-compatibility and

non-bio-toxicity for bio-medicine and clinical medical imaging [17-18].

Results and Discussions

99mTc-Fe3O4 magnetic nano-particles (

99mTc-MNP) solution was prepared by using magnet

adsorption method. We can observe the Fe3O4 magnetic nano-particles by using magnet adsorption

at lower layer in the bottle. The clear upper layer remains non-reaction of SnCl2·2H2O and Tc-99m

pertechnetate as Fig,1. According to the results of fig.2 to fig. 8 and table1, we can observe the

lower labeling efficiency of 99m

Tc- Fe3O4 when lacking of reducing agent of SnCl2·2H2O. 99m

Tc-labeling involves reduction of 99m

Tc7+

to an oxidation state that binds to a chelating molecules

of interest [14,17-18]. When reducing agent SnCl2·2H2O was solved in water of 6～7 of pH value,

the solution was found insoluble colloid to decrease the labeling efficiency of 99m

Tc- Fe3O4. It is not

ideal when reaction time is too long between SnCl2·2H2O with 99m

Tc- Fe3O4 solution[17-18].

According to the results of fig. 9, they displayed the significant difference when comparing the

reaction order of SnCl2 with that of 99m

Tc pertechnetate. It has higher labeling efficiency of 99m

Tc-MNP, when adding reducing agent step is faster than 99m

Tc pertechnate. The optimal reaction

time of SnCl2·2H2O with 99m

Tc is better under 1 hr from the results of table 1 and 2. According

to the results of table 2, 99m

Tc-MNP and 99m

Tc-dextran-MNP showed the 98.4% and 58.2% of

labeling efficiency under the same conc. of 6mM, 0.1 ml of SnCl2·2H2O , respectively. In 2005,

Matsunaga et al., found that cysteamine ligand coated by dextran and Tc-99m was shown 96%

of high labeling efficiency [18]. Nevertheless, the polymer-coated Fe3O4 magnetic nano-particle

labeled with 99m

Tc-pertechnetate decrease ca. 40 % of labeling efficiency when comparing the

non-polymer (dextran) Fe3O4 magnetic nano-particle.

Fig. 1 99m

Tc-MNP solution by using magnet adsorption method.

(a)Lower layer is the Fe3O4 magnetic nano-particles by using magnet adsorption (b) upper layer

remains non-reaction of SnCl2·2H2O and Tc-99m pertechnetate (c) anterior view of SnCl2·2H2O

solve in de-ion water (d) lateral view of in SnCl2 in de-ion water.

(a) (b)

(c) (d)

Applied Mechanics and Materials Vol. 459 53

Fig. 2 Effect of labeling efficiency of 99m

Tc-MNP solution when adding SnCl2·2H2O solution before

and after (a) 99m

Tc-MNPsolution without SnCl2·2H2O solution (b) labeling efficiency of 99m

Tc-MNP solution when adding 6mM of SnCl2·2H2O solution.

Fig. 3 The measured labeling efficiency for different volume( 0.1-0.7 ml) of SnCl2·2H2O

solution at fixed concentration condition( 0.1 mM and 0.5 mM). (a) fixed conc. of 0.1 mM of

SnCl2·2H2O (b) fixed conc. of 0.5 mM of SnCl2.2H2O .

Fig. 4 The measured labeling efficiency for different volume( 0.1-0.7 ml), of SnCl2·2H2O

solution at fixed concentration condition(0.1 mM and 0.5 mM). (a) fixed conc. of 1.0 mM of

SnCl2.2H2O (b) fixed conc. of 2.0 mM of SnCl2·2H2O .

(a) (b)

(a) (b)

(a) (b)

54 Applied Mechanics and Mechanical Engineering IV

Fig. 5 The measured labeling efficiency for different volume( 0.1-0.7 ml), of SnCl2·2H2O

solution at fixed concentration condition(0.1 mM and 0.5 mM).(a) fixed conc. of 4.0 mM of

SnCl2·2H2O (b) fixed conc. of 6.0 mM of SnCl2·2H2O .

Fig. 6 The measured labeling efficiency for different concentration (6 mM), shelf time(1

hour-1month) of SnCl2·2H2O solution at fixed volume condition (0.1 ml).

Fig. 7 The measured labeling efficiency for different concentration (0.1 mM and 0.3 mM) of

SnCl2·2H2O solution at fixed volume condition(0.1-0.7 ml).

(a) (b)

(a) (b)

Applied Mechanics and Materials Vol. 459 55

Fig. 8 The measured labeling efficiency for different concentration (0.1 mM - 6.0 mM) of

SnCl2·2H2O solution at fixed volume condition(0.5ml and0.7 ml).

Table 1 The labeling efficiency of 99m

Tc-MNP solution when using different molar concentration,

volume, reaction time (n=5)

SnCl2 different reaction time (min)

1 5 10 20 40 60

0 mM 13.6±3.2 15.0±1.4 14.5±1.6 14.9±2.4 18.6±1.3 16.4±3.1

0.1mM

(0.1ml)* 11.0±3.3 12.7±1.6 14.2±2.4 33.8±4.6 26.7±6.9 22.1±8.6

0.1mM

(0.3ml)* 9.76±2.2 13.1±9.0 16.1±5.6 25.2±7.2 26.7±5.8 22.9±4.7

0.1mM

(0.5ml)* 12.8±7.1 13.2±8.6 18.1±10.5 27.6±6.7 24.8±4.3 26.5±5.8

0.1mM

(0.7ml)* 12.8±1.6 18.7±0.5 24.9±4.0 33.2±2.2 29.5±4.0 27.1±3.3

0.5mM

(0.1ml)* 9.4±0.6 17.0±2.2 28.0±5.9 54.1±12.9 50.2±6.2 52.9±9.0

0.5mM

(0.3ml)* 13.2±1.0 20.0±2.4 29.2±2.2 60.9±4.9 57.7±6.4 70.2±6.9

0.5mM

(0.5ml)* 17.8±11.1 19.6±3.9 36.5±2.5 66.1±7.1 54.8±7.9 66.6±6.9

0.5mM

(0.7ml)* 14.7±1.0 21.4±2.4 44.5±9.5 66.9±5.4 62.4±9.1 64.9±15.0

1mM

(0.1ml)* 17.5±5.0 23.7±1.2 39.6±2.8 51.1±12.2 60.0±14.0 64.0±8.7

1mM

(0.3ml)* 24.6±2.6 35.0±2.6 52.4±2.5 62.5±8.0 70.5±6.1 79.6±8.0

1mM

(0.5ml)* 30.6±2.7 41.8±1.4 58.3±5.2 72.2±8.1 76.7±5.3 86.9±5.6

1mM

(0.7ml)* 31.5±3.4 35.0±8.1 69.2±4.9 72.7±6.1 81.3±4.7 88.3±7.2

2mM

(0.1ml)* 33.4±15.2 34.1±9.2 55.2±4.0 55.6±10.2 65.4±4.7 71.1±7.3

2mM

(0.3ml)* 45.0±9.3 50.7±8.2 70.1±3.4 78.0±6.9 75.3±9.4 79.1±5.3

(a) (b)

56 Applied Mechanics and Mechanical Engineering IV

2mM

(0.5ml)* 65.8±14.1 53.7±12.2 70.3±10.9 76.9±6.1 81.5±9.0 85.0±7.5

2mM

(0.7ml)* 70.0±3.9 75.2±3.8 79.7±4.8 78.7±9.2 85.8±6.8 84.5±8.0

4mM

(0.1ml)* 43.0±7.9 52.6±8.0 57.3±15.9 69.8±4.0 76.3±8.6 68.5±8.2

4mM

(0.3ml)* 55.4±3.3 76.8±1.9 79.8±2.3 86.8±8.0 95.4±1.6 80.0±8.5

4mM

(0.5ml)* 63.9±8.3 79.5±8.5 78.9±8.8 88.0±6.1 93.6±4.0 94.2±1.8

4mM

(0.7ml)* 73.1±12.9 85.6±8.8 86.9±9.0 90.4±3.0 95.0±2.8 95.8±2.4

6mM

(0.1ml)*** 89.7±6.9 96.9±2.4 92.8±1.5 97.3±1.2 98.3±1.3 98.4±1.0

6mM

(0.3ml)*** 42.0±17.3 79.6±4.0 75.9±10.2 81.5±4.7 83.1±1.5 96.0±2.1

6mM

(0.5ml)*** 24.8±2.8 55.4±5.4 60.0±8.0 64.2±3.4 77.6±3.9 92.7±4.3

6mM

(0.7ml)*** 30.2±6.6 49.3±1.9 58.3±3.4 60.1±4.9 66.6±4.9 85.7±7.2

6mM

(0.1ml)** 18.2±1.3 19.6±4.0 17.0±1.6 22.1±1.8 21.1±9.1 25.3±3.5

6mM

(0.3ml)** 23.7±4.2 23.6±2.2 27.0±3.0 22.9±4.8 19.1±6.8 16.0±3.8

6mM

(0.5ml)** 16.7±3.4 15.7±6.0 19.4±2.8 54.9±14.2 33.5±5.7 32.1±17.3

6mM

(0.7ml)** 19.5±2.3 21.1±2.5 22.2±8.6 30.8±1.7 40.8±4.5 30.6±3.3

*after 1week reaction time **after 1month reaction time *** after 1hour reaction time

Fig. 9 Effect of labeling efficiency of 99m

Tc-MNP and 99m

Tc-dextran-MNP for different reaction

priority of SnCl2·2H2O and 99m

Tc solution at fixed 6 mM, 0.1 ml of MNP (a) adding 99m

Tc first

and then SnCl2.2H2O (b) adding SnCl2·2H2O first, and then 99m

Tc (c) adding 99m

Tc-

MNP(commercial kit) first , and then SnCl2·2H2O (d) adding SnCl2·2H2O first ,and then 99m

Tc-

MNP (commercial kit) (e)adding 99m

Tc99m

Tc-dextran-MNP first, and then SnCl2·2H2O (f) adding

SnCl2·2H2O first, and then 99m

Tc-dextran-MNP.

Applied Mechanics and Materials Vol. 459 57

Table 2 The labeling efficiency and their stabilities of 99m

Tc-MNP( 99m

Tc- Fe3O4 magnetic

nano-particles) and 99m

Tc-dextran-MNP (n=5).

Group Labeling effect (%)* Stability (%)** 99m

Tc-MNP

(6mM 0.1ml SnCl2 ) 98.4±1.0 99.6±0.5

99m

Tc-MNP

(6mM 0.3ml SnCl2 ) 96.0±2.1 99.9±0.3

99mTc-MNP

(6mM 0.5ml SnCl2 ) 92.7±4.3 99.8±0.4

99mTc-MNP

(6mM 0.7ml SnCl2 ) 85.7±7.2 99.9±0.1

99mTc-Commercial MNP

(6mM 0.1ml SnCl2 ) 86.4±2.6 99.3±0.4

99mTc-dextran@MNP

(6mM 0.1ml SnCl2 ) 58.2±10.9 96.0±2.1

99mTc-MNP***

(6mM 0.1ml SnCl2 ) 97.8±1.2 99.5±0.3

99mTc-Commercial

MNP***

(6mM 0.1ml SnCl2 )

88.7±1.4 98.1±1.1

99mTc-dextran@MNP***

(6mM 0.1ml SnCl2 ) 74.6±2.5 97.2±1.8

*after 1hour reaction time ** after 2 hour reaction time

***adding SnCl2·2H2O solution first，and then Na99m

TcO4 solution next order

Conclusion

In biomedical diagnosis aspect, magnetic nanoparticle can be used as drug carrier and MRI, PET,

constract agents[19,20]. Magnetic fluid hyperthermia is one of the most important cancer

therapies. Magnetic nanoparticles play a key role due to their unique features as heating mediators

for hyperthermia[21]. In this study, Fe3O4 magnetic nanoparticle was prepared by using chemical

coprecipitation method. The preparation of Tc-99m pertechnetate with Fe3O4 magnetic

nano-particles by using magnet adsorption method. The Tc-99m labeling efficiency of in-house

Fe3O4 magnetic nanoparticles(MNP) and commercial kit were ca.98.4 % and 85% (n＝5), under the

same conc. of 6mM, 0.1 ml of SnCl2.2H2O , respectively. The Tc-99m labeling efficiency of

magnetic nanoparticles with its dextran-coated was ca. 58.2%(n＝5) at the same conc. and volume

of SnCl2.2H2O. The in-vitro stabilities of the 3 kinds of magnetite magnetic fluids were higher than

96.0%(n＝5) during 2hrs. The reducing agent of SnCl2.2H2O plays a key role due to its reducing

ability for Tc-99m pertechnetate. The optimal reaction time of SnCl2.2H2O with 99m

Tc is better

under 1 hour.

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