Summary

를 사용하여 금 나노 입자의 효율적인 방사성 표지를위한 최적화 된 프로토콜<sup> (125)</sup> I-표시 아 지드 보철 그룹

Published: October 10, 2016
doi:

Summary

I 125 – 표지 지드의 합성 및 무도 클릭 반응을 이용 dibenzocyclooctyne (DBCO) – 기 – 컨쥬 게이트 13 나노 크기의 금 나노 입자의 방사성 표지에 대한 세부 절차를 설명한다.

Abstract

Here, we demonstrate a detailed protocol for the radiosynthesis of a 125I-labeled azide prosthetic group and its application to the efficient radiolabeling of DBCO-group-functionalized gold nanoparticles using a copper-free click reaction. Radioiodination of the stannylated precursor (2) was carried out by using [125I]NaI and chloramine T as an oxidant at room temperature for 15 min. After HPLC purification of the crude product, the purified 125I-labeled azide (1) was obtained with high radiochemical yield (75 ± 10%, n = 8) and excellent radiochemical purity (>99%). For the synthesis of radiolabeled 13-nm-sized gold nanoparticles, the DBCO-functionalized gold nanoparticles (3) were prepared by using a thiolated polyethylene glycol polymer. A copper-free click reaction between 1 and 3 gave the 125I-labeled gold nanoparticles (4) with more than 95% of radiochemical yield as determined by radio-thin-layer chromatography (radio-TLC). These results clearly indicate that the present radiolabeling method using a strain-promoted copper-free click reaction will be useful for the efficient and convenient radiolabeling of DBCO-group-containing nanomaterials.

Introduction

The strain-promoted copper-free click reaction between azides and cyclooctynes has been extensively applied to the efficient bioorthogonal labeling of a wide range of biomolecules, nanomaterials, and living subjects1-7. Due to the excellent site-specificity and rapid reaction rate of this conjugation reaction, it has also been used to synthesize radiolabeled tracers. A few 18F-labeled azide or DBCO prosthetic groups have been prepared for in vitro labeling of various cancers targeting peptides and antibodies, as well as for in vivo pre-targeted imaging of tumors8-13. In addition to these examples, the same conjugation reaction was applied to the metal-radioisotope-labeling of nanomaterials for positron emission tomography (PET) imaging studies14-16.

For several decades, radioactive iodines have been used for biomedical research and clinical trials through PET imaging (124I), single-photon emission computed tomography (SPECT) imaging (123I, 125I), and thyroid cancer treatment (131I)17-21. Therefore, an efficient method for radioactive iodine labeling is fundamentally important for various investigations, including molecular imaging studies, analysis of organ distribution of biomolecules, biomarker identification, and drug development. A copper-free click reaction strategy could be used in radioactive iodine labeling. However, this application has not been investigated as extensively as 18F-labeled biomolecules22-23. Here, we will provide a step-by-step protocol for the synthesis of an 125I-labeled azide for radiolabeling of DBCO-group-derived molecules. The procedures in the present report will include radioiodination of the stannylated precursor, purification steps with HPLC, and solid phase extraction. We also demonstrate efficient radiolabeling of DBCO-group-modified 13-nm-sized gold nanoparticles using the 125I-labeled azide. The detailed protocol in this report will help synthetic chemists understand a new radiolabeling methodology for the synthesis of radiolabeled products.

Protocol

주의 : 방사성 요오드의 산화 된 형태가 매우 휘발성 적절한 리드 방패와 리드 유리 병 취급해야합니다. 모든 방사 단계는 통풍이 잘되는 숯을 여과 후드에서 수행 한 실험 절차는 방사능 검출 장치에 의해 모니터링해야한다. I 125 – 표지 된 아 지드의 합성 화학 및 역상 카트리지 (1)의 제조 용액의 시약의 조제 150 μL의 아 지드 전구체 (2) 무수 …

Representative Results

stannylated 전구체 (2)의 방사성 요오드화 반응은 방사능 표지 된 생성물을 제공하기 위해 실온에서 15 분 동안 [125 I] NaI를 아세트산 및 클로라민 T 150 MBq의를 사용하여 수행 하였다 (1). 조 혼합물을 예비 HPLC 정제 후, 목적 생성물을 방사 화학적 수율은 75 ± 10 % (N = 8)을 얻었다. HPLC 분석은 125 I 표지 된 생성물의 방사 화학적 순도는 99 %…

Discussion

일반적으로, 정제 된 I-125 표지 지드 (1)의 관찰 방사 화학적 수율은 75 ± 10 %이었다 (N = 8). 방사성 표지는 방사능 MBq의 50-150로 수행하고, 그 결과 방사 상당히 일치한다. [125 I]의 NaI (t 1/2 = 59.4 d) 방사성 요오드화 반응에 사용 하였다 개월 이상 방사성 붕괴를 시행 한의 방사 화학적 수율로 관찰하면 약간 (53~65%) 감소 하였다. 따라서, [125</su…

Divulgations

The authors have nothing to disclose.

Acknowledgements

This work was supported by grants from the National Research Foundation of Korea, funded by the government of the Republic of Korea, (Grant nos. 2012M2B2B1055245 and 2012M2A2A6011335) and by the RI-Biomics Center of Korea Atomic Energy Research Institute.

Materials

Chloramine T trihydrate Sigma 402869
[125I]NaI in aq. NaOH Perkin-Elmer NEZ033A010MC
Sodium metabisulfite  Sigma S9000
Formic acid Sigma 251364
Sep-Pak tC18 plus cartridge Waters WAT036800
Dimethyl sulfoxide  Sigma D2650
Acetone Sigma 650501
Ethanol Sigma 459844
Gold(III) chloride trihydrate Sigma 520918
Tween 20  Sigma P1379
DBCO PEG SH (MW 5000) NANOCS PG2-DBTH-5k
TLC silica gel 60 F254 Merck
Analytical HPLC Agilent 1290 Infinity Model number
Preparative HPLC Agilent 1260 Infinity Model number
Analytical C18 reverse-phase column Agilent Zorbax Eclipse XDB-C18
Preparative C18 reverse-phase column Agilent PrepHT XDB-C18
Radio TLC scanner Bioscan AR-2000 Model number
Radioisotope dose calibrator Capintec, Inc CRC -25R dose calibrator Model number

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Jeon, J., Shim, H. E., Mushtaq, S., Choi, M. H., Park, S. H., Choi, D. S., Jang, B. An Optimized Protocol for the Efficient Radiolabeling of Gold Nanoparticles by Using a 125I-labeled Azide Prosthetic Group. J. Vis. Exp. (116), e54759, doi:10.3791/54759 (2016).

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