{"id":83573,"date":"2025-03-12T23:00:34","date_gmt":"2025-03-12T14:00:34","guid":{"rendered":"https:\/\/www.waseda.jp\/top\/en\/?p=83573"},"modified":"2025-03-18T12:28:10","modified_gmt":"2025-03-18T03:28:10","slug":"life-in-a-nutshell-new-species-found-in-the-carapace-of-late-cretaceous-marine-turtle-2-2-2-2-2-2-2-2-2-2-2-3-3-2-2-3-2-3-2-2-2-3-2-2-2-3-3-2-2-3","status":"publish","type":"post","link":"https:\/\/www.waseda.jp\/top\/en\/news\/83573","title":{"rendered":"Lighting the Way: How Activated Gold Reveals Drug Movement in the Body"},"content":{"rendered":"

Lighting the Way: How Activated Gold Reveals Drug Movement in the Body<\/strong><\/h1>\n

Neutron activation of gold nanoparticles enables visualization of drug distribution in mice<\/em><\/p>\n

Tracking targeted drug delivery is often a challenge due to limitations in the current imaging techniques. A recent study by <\/strong>Tokyo\u2019s <\/strong>Waseda University, reports a breakthrough imaging technique that allows direct and highly sensitive tracking of gold nanoparticles (AuNPs) inside the body. This novel technique, which uses neutron activation of gold, could revolutionize cancer drug delivery by enabling real-time visualization of the gold nanoparticles without external tracers.<\/strong><\/p>\n

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Image title: Tracking Cancer Drug Delivery with Activated Gold Nanoparticles
\nImage caption: Researchers develop a novel activation imaging technique that enables real-time visualization of gold nanoparticles in the body without the use of external tracers.
\nImage credit: Nanase Koshikawa from Waseda University
\nLicense type: Original content
\nUsage restrictions: Cannot be reused without permission<\/p><\/div>\n

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Gold nanoparticles (AuNPs) are tiny gold particles of 1\u2013100 nanometers and have unique chemical and biological properties. Due to their potential to accumulate in tumors, these nanoparticles have emerged as promising drug carriers for cancer therapy and targeted drug delivery. However, tracking the movement of these nanoparticles in the body has been a major challenge. Traditional imaging methods often involve tracers like fluorescent dyes and radioisotopes, which give limited visualization and inaccurate results due to detachment from AuNPs.<\/p>\n

In a step to advance the imaging of AuNPs, researchers from Waseda University introduced a new imaging technique that uses neutron activation to transform stable gold into a radioisotope of gold and enables long-term tracking of the AuNPs within the body. The study was led by Nanase Koshikawa, a PhD student in the Graduate School of Advanced Science and Engineering at Waseda University, and Jun Kataoka, a Professor in the Faculty of Science and Engineering at Waseda University, in collaboration with Osaka University and Kyoto University. The findings of this study were published \u2026in the Volume, Issue, of Applied Physics Letters<\/em> on Month Day, 2025.<\/p>\n

\u201cTraditional imaging methods involve external tracers, which may detach during circulation<\/em>,\u201d explains Koshikawa. \u201cTo overcome this limitation, we directly altered the AuNPs, making them detectable via X-rays and gamma rays without the use of external tracers<\/em>.\u201d<\/p>\n

For activation of the AuNPs, the researchers irradiated the stable gold nanoparticles with neutrons, converting the stable (197<\/sup>Au) to radioactive (198<\/sup>Au). The radioactive 198<\/sup>Au emits gamma rays, which are detectable from outside the body. Prof. Kataoka explains neutron activation, stating, \u201cActivation of atoms through particle irradiation is a technique that directly alters the material. The altered elements are sometimes unstable and emit X-rays and gamma rays that make the material visible from outside the body. This does not change the atomic number, and thus the chemical properties of the element are preserved<\/em>.\u201d<\/p>\n

The researchers further confirmed the tracking of these radioactive AuNPs by injecting them into tumor-bearing mice and visualizing them using a special imaging system.<\/p>\n

Additionally, the study demonstrated this imaging technique for drug delivery of 211<\/sup>At, a radio-therapeutic drug used in targeted cancer therapy. The 211<\/sup>At emits alpha particles and X-rays, which are detectable for a shorter duration due to a shorter half-life. The researchers labeled the 211<\/sup>At with the radioactive AuNPs, forming 211<\/sup>At-labeled (198<\/sup>Au) AuNPs. This approach provided long-term imaging of the drug due to the longer half-life (2.7 days) of 198<\/sup>Au, overcoming the limitations of the short half-life of 211<\/sup>At.<\/p>\n

\u201c211<\/sup>At has a half-life of only 7.2 hours, and hence its emitted X-rays disappear within 2 days, but with the (<\/em>198<\/sup><\/em>Au) AuNPs labeling, we were able to track the drug\u2019s distribution for up to 5 days using gamma rays from \u00b9\u2079\u2078Au, which has a longer half-life of 2.7 days,\u201d <\/em>says co-author Atsushi Toyoshima from the Institute for Radiation Sciences, Osaka University.<\/p>\n

This study represents a breakthrough in the field of targeted drug delivery and could lead to major advancements in drug delivery systems. The direct tracking of AuNPs inside the body could pave the way for more effective cancer treatments with precise monitoring of drug distribution. The study could also open new possibilities for real-time pharmacokinetic studies, ensuring improved drug safety and efficacy. <\/strong><\/p>\n

\u201cAuNPs are being actively researched for medical applications,\u201d explains co-author Hiroki Kato from the Institute for Radiation Sciences, Osaka University. \u201cWe developed a simple and scalable technique for tracking AuNPs that could significantly advance nanomedicine while driving the optimization of gold-based nanomaterials.\u201d<\/em><\/p>\n

\u00a0<\/em>Reflecting on their plans, co-author Yuichiro Kadonaga, an Assistant Professor from the Institute for Radiation Sciences, Osaka University, shares his perspective, saying, \u201cWe plan to enhance the imaging resolution and extend this technique to various nanoparticle-based systems. By further refining neutron activation imaging, we aim to make drug monitoring a clinical reality, potentially revolutionizing the field of imaging technologies<\/em>.\u201d<\/p>\n

Reference<\/strong><\/p>\n

Title of original paper<\/strong>:Activation imaging of gold nanoparticles for versatile drug visualization: an in vivo demonstration
\nDOI<\/strong>:https:\/\/doi.org\/10.1063\/5.0251048<\/a>
\nJournal<\/strong>:Applied Physics Letters
\nArticle Publication Date:<\/strong>12 March 2025
\nAuthors<\/strong>:N. Koshikawa,1<\/sup> Y. Kikuchi,1<\/sup> K. S. Tanaka,1<\/sup> K. Tokoi,2<\/sup> A. Mitsukai,3<\/sup> H. Aoto,2<\/sup> Y. Kadonaga,3<\/sup> A. Toyoshima,3<\/sup> H. Kato,3<\/sup> K. Ooe,3<\/sup> K. Takamiya,4<\/sup> and J. Kataoka1<\/sup>
\nAffiliations:
\n<\/strong>1<\/sup>Graduate School of Advanced Science and Engineering, Waseda University, Japan
\n2<\/sup>Department of Chemistry, Graduate School of Science, Osaka University, Japan
\n3<\/sup>Institute for Radiation Sciences, Osaka University, Japan
\n4<\/sup>Institute for Integrated Radiation and Nuclear Science, Kyoto University, Japan<\/p>\n

About Nanase Koshikawa from Waseda University<\/strong><\/p>\n

Ms. Nanase Koshikawa is a PhD student at the Graduate School of Advanced Science and Engineering, Waseda University, Japan. She specializes in advanced imaging techniques for nuclear medicine and is developing high-resolution imaging systems for detecting high-energy gamma rays. In November 2024, she presented a new SPECT system at the 6th<\/sup> International Workshop on New Photon-Detectors (PD24), which overcomes the limitations of traditional SPECT systems, improving accuracy in medical imaging. Her key research areas include high-resolution imaging, photon imaging, and radio imaging.<\/p>\n","protected":false},"excerpt":{"rendered":"

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