Nano-graphene oxide composite for in vivo imaging

Sung-Chan Jang,1,2,* Sung-Min Kang,1,* Jun Young Lee,3,* Seo Yeong Oh,1 AT Ezhil Vilian,4 Ilsong Lee,1,2 Young-Kyu Han,4 Jeong Hoon Park,3 Wan-Seob Cho,5,* Changhyun Roh,2,6 Yun Suk Huh1 1Department of Biological Engineering, Biohybrid Systems Research Center (BSRC), Inha University, Incheon, 2Biotechnology Research Division, 3Radiation Instrumentation Research Division, Advanced Radiation Technology Institute (ARTI), Korea Atomic Energy Research Institute (KAERI), Jeongeup, 4Department of Energy and Materials Engineering, Dongguk University, Seoul, 5Laboratory of Toxicology, Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, Busan, 6Radiation Biotechnology and Applied Radioisotope Science, University of Science and Technology (UST), Daejeon, Republic of Korea *These authors contributed equally to this work Introduction: Positron emission tomography (PET) tracers has the potential to revolutionize cancer imaging and diagnosis. PET tracers offer non-invasive quantitative imaging in biotechnology and biomedical applications, but it requires radioisotopes as radioactive imaging tracers or radiopharmaceuticals. Method: This paper reports the synthesis of 18F-nGO-PEG by covalently functionalizing PEG with nano-graphene oxide, and its excellent stability in physiological solutions. Using a green synthesis route, nGO is then functionalized with a biocompatible PEG polymer to acquire high stability in PBS and DMEM. Results and discussion: The radiochemical safety of 18F-nGO-PEG was measured by a reactive oxygen species and cell viability test. The biodistribution of 18F-nGO-PEG could be observed easily by PET, which suggested the significantly high sensitivity tumor uptake of 18F-nGO-PEG and in a tumor bearing CT-26 mouse compared to the control. 18F-nGO-PEG was applied successfully as an efficient radiotracer or drug agent in vivo using PET imaging. This article is expected to assist many researchers in the fabrication of 18F-labeled graphene-based bio-conjugates with high reproducibility for applications in the biomedicine field. Keywords: graphene oxide, nanocomposite, imaging, radiotrace

Voltametrické stanovení sumy ethylvanilinu a methylvanilinu ve vybraných vzorcích potravin pomocí uhlíkové pastové elektrody modifikované dodecylsíranem sodným

A new voltammetric method without using high cost and health risk nanomaterials has been developed for quantitative determination of ethylvanillin and methylvanillin sum, compounds that are used as food additives. The method is based on direct electrochemical oxidation of these biologically active compounds using square wave voltammetry at carbon paste electrode with surface modified by sodium dodecyl sulfate (SDS/CPE) performed in 0.1 M phosphate pH 6.0 buffer. Working conditions such as pH value of supporting electrolyte, type of surfactant, accumulation time of surfactant, and parameters of square wave voltammetry were optimized. In comparison with bare carbon paste electrode, excellent reproducibility characterized by a relative standard deviation of approximately 0.3% was obtained at the SDS/CPE. Linear range from 1.0 x 10(-6) to 2.0 x 10(-5) M, limits of quantification 9.8 x 10(-8) M and detection 2.9 x 10(-8) M were found at pulse amplitude 70 mV and frequency 50 Hz selected as optimum for ethylvanillin quantification. For methylvanillin, a linear range from 7.0 x 10(-8) to 2.0 x 10(-5) M and limits of quantification 7.0 x 10(-8) M and detection 2.0 x 10(-8) M were also determined. The procedure was validated using standard high-performance liquid chromatography method in the analysis of selected complex foodstuffs such as commercial baking sugar, biscuits, and an alcoholic drink. The results showed that a direct voltammetric approach is economically advantageous and reliable for the determination of ethyl- and methylvanillin, which is fully comparable to the reverse phase HPLC used as the ISO standard.Byla vyvinuta nová voltametrická metoda pro kvantitativní stanovení celkové sumy potravinářských aditiv ethylvanilinu a methylvanilinu bez použití vysokonákladových nanomateriálů vykazujících zdravotní rizika. Tato metoda je založena na přímé elektrochemické oxidaci těchto biologicky aktivních sloučenin s použitím square wave voltametrie na uhlíkové pastovité elektrodě povrchově modifikované dodecylsulfátem sodným (SDS/CPE) v prostředí 0,1 M fosfátového pufru o pH 6,0. Byly optimalizovány pracovní podmínky, jako je hodnota pH použítého elektrolytu, typ povrchově aktivníholátky, doba akumulace a parametry použité voltametrické techniky. Ve srovnání s nemodifikovanou elektrodou byla u SDS/CPE dosažena vynikající reprodukovatelnost charakterizovaná relativní směrodatnou odchylkou přibližně 0,3%. Lineární rozsah kalibrace od 1,0 x 10 (-6) do 2,0 x 10 (-5) M byl zjištěn limit kvantifikace 9,8 x 10 (-8) M a detekce 2,9 x 10 (-8) M při amplitudě 70 mV a frekvenci 50 Hz, které byly vybrány jako optimální pro kvantifikaci ethylvanilinu. Pro methylvanilin byl také stanoven lineární rozsah od 7,0 x 10 (-8) do 2,0 x 10 (-5) M a limit kvantifikace 7,0 x 10 (-8) M a detekce 2,0 x 10 (-8) M. Metoda byla dále validována pomocí standardní metody vysokoúčinné kapalinové chromatografie při analýze vybraných potravin, jako byl komerční pekárenský cukr, sušenky a alkoholický nápoj. Výsledky ukázaly, že přímý voltametrický přístup je ekonomicky výhodný a spolehlivý pro stanovení ethyl- a methylvanilinu, který je plně srovnatelný s HPLC na reverzní fázi používané jako ISO norma