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Rengaraj, Arunkumar,Haldorai, Yuvaraj,Puthiaraj, Pillaiyar,Hwang, Seung Kyu,Ryu, Taegong,Shin, Junho,Han, Young-Kyu,Ahn, Wha-Seung,Huh, Yun Suk American Chemical Society 2017 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.56 No.17
<P>A microporous covalent triazine polymer (CTP) is synthesized via a Friedel-Crafts reaction and used as a solid support to immobilize magnetite Fe3O4 nano-particles. Thermogravimetric analysis shows that approximately 60 wt % Fe3O4 is loaded onto the composite, and transmission electron microscopy analysis illustrates that the Fe3O4 nanoparticles are uniformly impregnated into the CTP surface. The CTP-Fe3O4 nanocomposite is an efficient adsorbent for the removal of strontium ion (Sr2+) from seawater. Response surface methodology, employed to optimize the removal of Sr2+, confirms that the optimal conditions for this removal are 0.55 mg, pH 7, 40 degrees C, and 250 min. The experimental results illustrate that the adsorption process fits well with the Freundlich isotherm, with a correlation coefficient of 0.976 and a maximum adsorption capacity of 128 mg g(-1). The kinetic study demonstrates that the adsorption behavior follows pseudo-second-order kinetics. The adsorbent is easily recovered from seawater using an external magnetic field, thereby offering facile and economic separation of the adsorbent.</P>
Rengaraj, Arunkumar,Puthiaraj, Pillaiyar,Heo, Nam-Su,Lee, Hoomin,Hwang, Seung Kyu,Kwon, Soonjo,Ahn, Wha-Seung,Huh, Yun-Suk Elsevier 2017 Colloids and surfaces Biointerfaces Vol.160 No.-
<P><B>Abstract</B></P> <P>Metal-organic frameworks are a novel class of organic-inorganic hybrid polymer with potential applications in bioimaging, drug delivery, and ROS therapy. NH<SUB>2</SUB>-MIL-125, which is a titanium-based metal organic framework with a large surface area of 1540m<SUP>2</SUP>/g, was synthesized using a hydrothermal method. The material was characterized by powder X-ray diffreaction (PXRD), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM), and N<SUB>2</SUB> isotherm analyses. The size of the polymer was reduced to the nanoscale using a high-frequency sonication process. PEGylation was carried out to improve the stability and bioavailability of the NMOF. The as-synthesized nano-NH<SUB>2</SUB>-MIL-125/PEG (NMOF/PEG) exhibited good biocompatibility over the (Cancer) MCF-7 and (Normal) COS-7 cell line. The interaction of NMOF/PEG with the breast cancer cell line (MCF-7) was examined by BIO-TEM analysis and laser confocal imaging. 2′,7′–dichlorofluorescin diacetate (DCFDA) analysis confirmed that NMOF/PEG produced free radicals inside the cancer cell line (MCF-7) upon visible light irradiation. NMOF/PEG absorbed a large amount of DOX (20wt.% of DOX) and showed pH, and photosensitive release. This controlled drug delivery was attributed to the presence of NH<SUB>2</SUB>, Ti group in MOF and a hydroxyl group in PEG. This combination of chemo- and ROS-therapy showed excellent efficiency in killing cancer MCF-7 cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PEG coated nano NH<SUB>2</SUB>-MIL-125 (NMOF) was synthesized via sonication process. </LI> <LI> NMOF/PEG exhibited good biocompatibility over both cancer and noncancer cell line. </LI> <LI> Biocompatible NMOF/PEG was applied for cancer doxorubicin (DOX) drug delivery. </LI> <LI> NMOF/PEG-DOX interaction with cancer cell was examined by BIO-TEM and confocal imaging. </LI> <LI> NMOF/PEG-DOX with ROS induction had a higher cytotoxicity on cancer cell than NMOF. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Rengaraj, Arunkumar,Haldorai, Yuvaraj,Kwak, Cheol Hwan,Ahn, Seungbae,Jeon, Ki-Joon,Park, Seok Hoon,Han, Young-Kyu,Huh, Yun Suk The Royal Society of Chemistry 2015 Journal of Materials Chemistry B Vol.3 No.30
<P>We demonstrated a non-enzymatic cholesterol sensor based on a nickel oxide (NiO) and high quality graphene composite for the first time. Graphene was grown by a chemical vapor deposition technique (CVD). The nanocomposite was fabricated through the electrodeposition of nickel hydroxide onto the surface of the CVD-grown graphene, which was followed by thermal annealing. The successful formation of the NiO/graphene composite was confirmed by X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. The deposition of flower-like NiO onto the graphene surface was confirmed by scanning electron microscopy. Electrochemical analyses were conducted to investigate the characteristics of the sensor during the detection of cholesterol. The sensor showed a high sensitivity of 40.6 mA μM<SUP>−1</SUP> cm<SUP>−2</SUP>, a rapid response time of 5 s, and a low detection of limit of 0.13 μM. We also investigated the effects of common interfering substances on the ability of the sensor to detect cholesterol. Furthermore, we successfully determined the cholesterol in a milk sample using the developed sensor. The composite electrode exhibited excellent detection of cholesterol with good reproducibility and long-term stability owing to the combined effects of NiO and graphene.</P>
Porous Covalent Triazine Polymer as a Potential Nanocargo for Cancer Therapy and Imaging
Rengaraj, Arunkumar,Puthiaraj, Pillaiyar,Haldorai, Yuvaraj,Heo, Nam Su,Hwang, Seung-Kyu,Han, Young-Kyu,Kwon, Soonjo,Ahn, Wha-Seung,Huh, Yun Suk American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.14
<P>A microporous covalent triazine polymer (CTP) network with a high surface area was synthesized via the Friedel-Crafts reaction and employed as a potential transport system for drug delivery and controlled release. The CTP was transformed to the nanoscale region by intense ultrasonication followed by filtration to yield nanoscale CTP (NCTP). This product showed excellent dispersibility in physiological solution while maintaining its chemical structure and porosity. An anticancer drug, doxorubicin (DOX), was loaded onto the NCTP through hydrophobic and pi-pi interactions, and its release was controlled at pH 4.8 and 7.4. The NCTP showed no toxicity toward cancer or normal cells, but the NCTP-DOX complex showed high efficacy against both types of cells in vitro. In-vitro cell imaging revealed that NCTP is a potential material for bioimaging. The potency of NCTP on cellular senescence was confirmed by the expression of senescence associated marker proteins p53 and p21. These results suggest that NCTP can be used as a new platform for drug delivery and imaging with potential applications in diagnosis and therapy.</P>
Vinothkumar, G.,Rengaraj, S.,Arunkumar, P.,Cha, Suk Won,Suresh Babu, K. American Chemical Society 2019 The Journal of Physical Chemistry Part C Vol. No.
<P>The antioxidant activity of cerium oxide nanoparticles (CNPs) depends on the concentration of oxygen vacancies and Ce<SUP>3+</SUP> active sites. In the present work, we report the impact of 5 mol % trivalent rare-earth-doped (RE<SUP>3+</SUP> = Eu<SUP>3+</SUP>, Nd<SUP>3+</SUP>, Pr<SUP>3+</SUP>, and La<SUP>3+</SUP>) CNPs on the oxidation state modulation and antioxidant property with respect to ionic radii. An increase in the lattice parameter, strain, and oxygen vacancy concentration was observed as a function of ionic radii. Among the various dopants in CNPs, La<SUP>3+</SUP> with higher ionic radii having smaller crystallite size (7.9 nm) and higher vacancy displayed better peroxidase, oxidase, and hydroxyl radical (HO<SUP>•</SUP>) scavenging activities. The kinetic parameters for the peroxidase and oxidase activities were found to be superior with <I>K</I><SUB>m</SUB> = 0.217 and 0.261 mM, respectively, for 5 mol % La<SUP>3+</SUP>-doped CNPs. To divulge the role of dopant concentration on the structural properties, we also explored using 10 and 20 mol % La<SUP>3+</SUP> doping in CNPs. Because of the smaller crystallite size (6.7 nm) and higher defect level (3.12 × 10<SUP>21</SUP> cm<SUP>-3</SUP>), 20% La<SUP>3+</SUP> doping showed superior peroxidase and oxidase activities, as shown by the low <I>K</I><SUB>m</SUB> values. CNPs exhibit both peroxidase and oxidase activities in a concentration-dependent manner. Moreover, CNPs exhibit concentration-dependent peroxidase and oxidase activities that can be selectively activated for various theranostic applications. Thus, our results demonstrate the crucial role of ionic radii and the concentration of RE<SUP>3+</SUP> dopants on defect formation in CNPs for improved antioxidant properties of ceria.</P> [FIG OMISSION]</BR>
Curcumin-Conjugated Gold Clusters for Bioimaging and Anticancer Applications
Govindaraju, Saravanan,Rengaraj, Arunkumar,Arivazhagan, Roshini,Huh, Yun-Suk,Yun, Kyusik American Chemical Society 2018 Bioconjugate chemistry Vol.29 No.2
<P>Curcumin-conjugated gold clusters (CUR-AuNCs) were synthesized using a “green” procedure and utilized as an anticancer and a bioimaging agent. Curcumin is a well-known anticancer agent, which forms a cluster when reacting with a gold precursor under mild alkali condition. A fluorescence spectroscopy analysis showed that the CUR-AuNCs emitted red fluorescence (650 nm) upon visible light (550) irradiation. Fourier transform infrared spectroscopy analysis confirmed the stretching and bending nature between the gold atoms and curcumin. Meanwhile, transmission electron microscopy analysis showed a cluster of approximately 1–3 nm with a uniform size. Time-resolved fluorescence analysis demonstrated that the red fluorescence was highly stable. Moreover, laser confocal imaging and atomic force microscopy analysis illustrated that a cluster was well distributed in the cell. This cluster exhibited less toxicity in the mortal cell line (COS-7) and high toxicity in the cervical cancer cell line (HeLa). The results demonstrated the conjugation of curcumin into the fluorescent gold cluster as a potential material for anticancer therapy and bioimaging applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/bcches/2018/bcches.2018.29.issue-2/acs.bioconjchem.7b00683/production/images/medium/bc-2017-00683j_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/bc7b00683'>ACS Electronic Supporting Info</A></P>