• 대한방사성의약품학회지
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• 제9권1호
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• pp.9-16
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• 2023

Liposomes as drug delivery system have proved useful carrier for various disease, including cancer. In addition, perfluorocarbon cored microbubbles are utilized in conjunction with high-intensity focused-ultrasound (HIFU) to enable simultaneous diagnosis and treatment. However, microbubbles generally exhibit lower drug loading efficiency, so the need for the development of a novel liposome-based drug delivery material that can efficiently load and deliver drugs to targeted areas via HIFU. This study aims to develop a liposome-based drug delivery material by introducing a substance that can burst liposomes using ultrasound energy and confirm the ability to target tumors using PET imaging. Liposomes (Lipo-DOX, Lipo-DOX-Au, Lipo-DOX-Au-RGD) were synthesized with gold nanoparticles using an avidin-biotin bond, and doxorubicin was mounted inside by pH gradient method. The size distribution was measured by DLS, and encapsulation efficiency of doxorubicin was analyzed by UV-vis spectrometer. The target specificity and cytotoxicity of liposomes were assessed in vitro by glioblastoma U87mg cells to HIFU treatment and analyzed using CCK-8 assay, and fluorescence microscopy at 6-hour intervals for up to 24 hours. For the in vivo study, U87mg model mouse were injected intravenously with 1.48 MBq of ⁶⁴Cu-labeled Lipo-DOX-Au and Lipo-DOX-Au-RGD, and PET images were taken at 0, 2, 4, 8, and 24 hours. As a result, the size of liposomes was 108.3 ± 5.0 nm at Lipo-DOX-Au and 94.1 ± 12.2 nm at Lipo-DOX-Au-RGD, and it was observed that doxorubicin was mounted inside the liposome up to 52%. After 6 hours of HIFU treatment, the viability of U87mg cells treated with Lipo-DOX-Au decreased by around 20% compared to Lipo-DOX, and Lipo-DOX-Au-RGD had a higher uptake rate than Lipo-DOX. In vivo study using PET images, it was confirmed that ⁶⁴Cu-Lipo-DOX-Au-RGD was taken up into the tumor immediately after injection and maintained for up to 4 hours. In this study, drugs released from liposomes-gold nanoparticles via ultrasound and RGD targeting were confirmed by non-invasive imaging. In cell-level experiments, HIFU treatment of gold nanoparticle-coupled liposomes significantly decreased tumor survival, while RGD-liposomes exhibited high tumor targeting and rapid release in vivo imaging. It is expected that the combination of these models with ultrasound is served as an effective drug delivery material with therapeutic outcomes.

• 한국토양비료학회지
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• 제11권2호
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• pp.67-73
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• 1979

배추 재배(栽培) 토양에의 석회시용(石灰施用)이 가리평형(加里平衡) activity ratio와 가리(加里) 흡수(吸收)에 미치는 영향(影響)을 요약(要約)해 보면 다음과 같다. 1. 토양의 가리(加里) 평형(平衡) activity ratio는 소석회(消石灰)를 10a 당 160kg를 시용(施用)했을 때 그 값은 상승(上昇)한다. 일반적(一般的)으로 석회시용(石灰施用)과 가리(加里) 비료(肥料) 시용(施用)은 $AR^k_e$를 상승(上昇)시키는데 복합적(複合的)인 효과가 있음을 확인(確認)했다. 2. 치환성(置換性) K와 전기 전도도(電導度)는 석회시용(石灰施用)에 의(依)해서 증가된다. 석회(石灰) 시용(施用) 토양의 치환성(置換性) K 평균치(平均値)는 0.71m.e./100g(건토(乾土))이고 대조 토양(土壤)의 평균치(平均値)는 0.64m.e./100g(건토(乾土))이다. 전기 전도도(傳導度)는 석회(石灰) 시용(施用) 토양에서 $766{\mu}mho$이고 대조 토양은 $750{\mu}mho$이다. 3. 석회시용(石灰施用)에 의(依)해서 $AR^k_e$가 상승(上昇)하는 이유(理由)는 토양의 고액상(固液相) 간(間) 가리(加里) 평형계(平衡系)에 있어서 K, Ca, Mg을 고상(固相)으로 부터 액상(液相)으로 방출(放出)시키기 때문에 평형액(平衡液)의 $K^+$와 $Ca^{2+}+Mg^{2+}$ 농도(濃度)가 높아진데 기인(起因)된다고 본다. 4. K의 Ca에 의(依)한 치환(置換) 방출(放出)에 소요(所要)되는 exchange energy는 석회(石灰)를 시용(施用)한 토양에서 무가리구는 -3887, 200 kg $K_2O/ha$ 구는 -3778, 350 kg $K_2O/ha$ 구에서는 -3737 calories/chemical equivalent이고 대조구 토양은 가리(加里) 수준(水準)에 따라서 각각 -3983, -4392, -4228 calorie이다. 5. 식물체(植物體)의 K 흡수량(吸收量), 건물중(乾物重)은 석회(石灰)를 시용(施用)한 토양에서 생육(生育)한 시료(試料)가 대조구보다 많은 경향(傾向)이다.