Dual Stimuli-Triggered Nanogels in Response to Temperature and pH Changes for Controlled Drug Release

Kim, Yun Kyoung,Kim, Eun-Joong,Lim, Jae Hyun,Cho, Heui Kyoung,Hong, Woo Jin,Jeon, Hyang Hwa,Chung, Bong Geun Springer US 2019 NANOSCALE RESEARCH LETTERS Vol.14 No.1

<P>Poly-<I>N</I>-isopropyl acrylamide (PNIPAM) nanogels have been modified with different acrylic acid (AAc) contents for the efficient control of lower critical solution temperature (LCST). In this study, PNIPAM-co-AAc nanogels nanogels showed two volume phase transitions in comparison with PNIPAM. The transition temperature of PNIPAM nanogels was increased with AAc contents. The controlled drug release performance of PNIPAM-co-AAc nanogels loaded with β-lapachone was attributed to the AAc content ratio and was efficiently triggered in response to temperature and pH. Moreover, a colorimetric cell proliferation assay and direct fluorescence-based live/dead staining were used to confirm the concurrence on drug release profiles. Finally, PNIPAM-co-AAc20 showed a relatively low level of drug release in the range of acidic to neutral pH at body temperature, while maximizing drug release at basic pH. Therefore, we demonstrated that the PNIPAM-based nanogel with the temperature- and pH-responsive features could be a promising nanocarrier for potential intestine-specific drug delivery.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (10.1186/s11671-019-2909-y) contains supplementary material, which is available to authorized users.</P>

Reduced graphene oxide/carbon double-coated 3-D porous ZnO aggregates as high-performance Li-ion anode materials

Wi, Sungun,Woo, Hyungsub,Lee, Sangheon,Kang, Joonhyeon,Kim, Jaewon,An, Subin,Kim, Chohui,Nam, Seunghoon,Kim, Chunjoong,Park, Byungwoo Springer US 2015 NANOSCALE RESEARCH LETTERS Vol.10 No.1

<P>The reduced graphene oxide (RGO)/carbon double-coated 3-D porous ZnO aggregates (RGO/C/ZnO) have been successfully synthesized as anode materials for Li-ion batteries with excellent cyclability and rate capability. The mesoporous ZnO aggregates prepared by a simple solvothermal method are sequentially modified through distinct carbon-based double coating. These novel architectures take unique advantages of mesopores acting as space to accommodate volume expansion during cycling, while the conformal carbon layer on each nanoparticle buffering volume changes, and conductive RGO sheets connect the aggregates to each other. Consequently, the RGO/C/ZnO exhibits superior electrochemical performance, including remarkably prolonged cycle life and excellent rate capability. Such improved performance of RGO/C/ZnO may be attributed to synergistic effects of both the 3-D porous nanostructures and RGO/C double coating.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1186/s11671-015-0902-7) contains supplementary material, which is available to authorized users.</P>

Studies on the mechanical stretchability of transparent conductive film based on graphene-metal nanowire structures

Lee, Mi-Sun,Kim, Joohee,Park, Jihun,Park, Jang-Ung Springer US 2015 NANOSCALE RESEARCH LETTERS Vol.10 No.1

<P>Transparent electrodes with superior flexibility and stretchability as well as good electrical and optical properties are required for applications in wearable electronics with comfort designs and high performances. Here, we present hybrid nanostructures as stretchable and transparent electrodes based on graphene and networks of metal nanowires, and investigate their optical, electrical, and mechanical properties. High electrical and optical characteristics, superb bendability (folded in half), excellent stretchability (10,000 times in stretching cycles with 100% in tensile strain toward a uniaxial direction and 30% in tensile strain toward a multi-axial direction), strong robustness against electrical breakdown and thermal oxidation were obtained through comprehensive study. We believe that these results suggest a substantial promise application in future electronics.</P>

Magnetic and electric properties of stoichiometric BiMnO ₃ thin films

Lee, Bo Wha,Yoo, Pil Sun,Nam, Vu Binh,Toreh, Kirstie Raquel Natalia,Jung, Chang Uk Springer US 2015 NANOSCALE RESEARCH LETTERS Vol.10 No.1

<P>It has been suggested that BiMnO<SUB>3</SUB> is a material exhibiting both ferromagnetism and ferroelectricity. Stoichiometry is rather easily achieved in a polycrystalline sample, and ferromagnetic properties have been well documented for bulk samples. Stoichiometry in thin films has been difficult to obtain, and many physical properties have exhibit wide distributions mainly due to the stoichiometry problem. Thin film studies on BiMnO<SUB>3</SUB> have not shown clear evidence of ferroelectricity, while other physical properties measured for the BiMnO<SUB>3</SUB> films showed wide spectra, which has been attributed to cation and/or oxygen vacancies. We fabricated BiMnO<SUB>3</SUB> thin films with good stoichiometry and with ferromagnetic properties comparable to those reported for stoichiometric BiMnO<SUB>3</SUB>: <I>Tc</I> ~ 105 K and <I>M</I><SUB>sat</SUB> ~ 3.6 μ<SUB>B</SUB>/Mn. The charge-electric field (Q-E) curve measured at 5 K was fairly linear and free from hysteresis and showed no ferroelectric order. This finding is consistent with the centrosymmetric crystal structure recently suggested by theoretical calculations and structural studies on ceramic samples of stoichiometric BiMnO<SUB>3</SUB>.</P>

Glaucine inhibits breast cancer cell migration and invasion by inhibiting MMP-9 gene expression through the suppression of NF-κB activation

Kang, Hyereen,Jang, Sung-Wuk,Pak, Jhang Ho,Shim, Sungbo Springer US 2015 MOLECULAR AND CELLULAR BIOCHEMISTRY - Vol.403 No.1

<P> Matrix metalloproteinase-9 (MMP-9) plays a central role in the invasion and metastasis of various types of cancer cells. Here, we demonstrate that glaucine, an alkaloid isolated from the plant<I> Corydalis turtschaninovii</I> tuber (Papaveraceae), can inhibit the migration and invasion of human breast cancer cells. We further show that glaucine significantly blocks phorbol 12-myristate 13-acetate (PMA)-induced MMP-9 expression and activity in a dose-dependent manner. Results from reporter gene and electrophoretic mobility shift assays revealed that glaucine inhibits MMP-9 expression by suppressing activation of the nuclear transcription factor nuclear factor-κB (NF-κB). Moreover, glaucine attenuates PMA-induced IκBα degradation and nuclear translocation of NF-κB. Finally, we also found that glaucine inhibits invasion and MMP-9 expression in the highly metastatic MDA-MB-231 breast cancer cell line. Taken together, our findings indicate that the MMP-9 inhibitory activity of glaucine and its abilities to attenuate IκBα and NF-κB activities may be therapeutically useful as a novel means of controlling breast cancer growth and invasiveness.</P>

Morphological and SERS Properties of Silver Nanorod Array Films Fabricated by Oblique Thermal Evaporation at Various Substrate Temperatures

Oh, Myoung-Kyu,Shin, Yong-Seok,Lee, Chang-Lyoul,De, Ranjit,Kang, Hoonsoo,Yu, Nan Ei,Kim, Bok Hyeon,Kim, Joon Heon,Yang, Jin-Kyu Springer US 2015 NANOSCALE RESEARCH LETTERS Vol.10 No.1

<P>Aligned silver nanorod (AgNR) array films were fabricated by oblique thermal evaporation. The substrate temperature during evaporation was varied from 10 to 100 °C using a home-built water cooling system. Deposition angle and substrate temperature were found to be the most important parameters for the morphology of fabricated films. Especially, it was found that there exists a critical temperature at ~90 °C for the formation of the AgNR array. The highest enhancement factor of the surface-enhanced Raman scattering (SERS), observed in the Ag films coated with benzenethiol monolayer, was ~6 × 10<SUP>7</SUP>. Hot spots, excited in narrow gaps between nanorods, were attributed to the huge enhancement factor by our finite-difference time-domain (FDTD) simulation reflecting the real morphology.</P>

Cucurbitacin D induces cell cycle arrest and apoptosis by inhibiting STAT3 and NF-κB signaling in doxorubicin-resistant human breast carcinoma (MCF7/ADR) cells

Ku, Jin Mo,Kim, Soon Re,Hong, Se Hyang,Choi, Han-Seok,Seo, Hye Sook,Shin, Yong Cheol,Ko, Seong-Gyu Springer US 2015 MOLECULAR AND CELLULAR BIOCHEMISTRY - Vol.409 No.1

<P>Breast cancer is the most common cancer for women and is a major cause of mortality in women. Doxorubicin is a generally used chemotherapy drug for breast cancer. However, multidrug resistance of breast cancer interferes with the chemotherapy. We examined whether cucurbitacin D affects doxorubicin resistance of MCF7/ADR breast cancer cells. Cell viability was measured by MTT assay. Levels of p-STAT3, p-NF-κB, IκB, and caspases were measured by Western blot analysis. Nuclear staining of Stat3 and NF-κB was measured by immunocytochemistry. STAT3 and NF-κB transcriptional activity was detected by STAT3 and NF-κB luciferase reporter gene assays. Analysis of cell cycle arrest was performed by flow cytometry. Induction of apoptosis by cucurbitacin D was measured by Annexin V-FITC/propidium iodide assay. More than 90 % of MCF7/ADR cells lived upon treatment with doxorubicin for 24 h. However, upon treatment with cucurbitacin D, cell death was more than 60 %. Co-administration of cucurbitacin D and doxorubicin induced apoptosis, and G2/M cell cycle arrest, and inhibited upregulated Stat3 by doxorubicin on MCF7/ADR cells. Additionally, cucurbitacin D led to an increase in the IκBα level in the cytosol and a decrease in the p-NF-κB level in the nucleus. Finally, cucurbitacin D inhibited translocation of Stat3 and NF-κB and decreased transcriptional activity in the nucleus. Cucurbitacin D decreases cell proliferation and induces apoptosis by inhibiting Stat3 and NF-κB signaling in doxorubicin-resistant breast cancer cells. Cucurbitacin D could be used as a useful compound to treat adriamycin-resistant patients.</P>

Memory Impairment in Estrogen Receptor α Knockout Mice Through Accumulation of Amyloid-β Peptides

Hwang, Chul Ju,Yun, Hyung-Mun,Park, Kyung-Ran,Song, Ju Kyung,Seo, Hyun Ok,Hyun, Byung Kook,Choi, Dong Young,Yoo, Hwan-Soo,Oh, Ki-Wan,Hwang, Dae Yeun,Han, Sang-Bae,Hong, Jin Tae Springer US 2015 Molecular Neurobiology Vol.52 No.1

<P>Estrogen has been known to reduce the development of Alzheimer’s disease (AD). However, exact mechanisms are not clear. We investigated whether estrogen can increase amyloid-beta (Aβ) degradation and affects Aβ-induced memory impairment in an estrogen deficiency model. Estrogen receptor alpha (ERα) knockout mice and wild-type mice were intracerebroventricular (ICV) infused with Aβ (300 pmol) for 2 weeks. Cognitive function was then assessed by the Morris water maze test and passive avoidance test. In addition, Western blot analysis, immunostaining, immunofluorescence staining, ELISA, and enzyme activity assays were used to examine the degree of Aβ deposition in the brains of ERα knockout mice. In our present study, Aβ was accumulated more in the ERα knockout mice brain and greatly worsened memory impairment and glial activation as well as neurogenic inflammation. These results suggest that estrogen may protect memory impairment by stimulating the degradation of Aβ and down-regulate neurogenic inflammation as well as amyloidogenesis.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1007/s12035-014-8853-z) contains supplementary material, which is available to authorized users.</P>

Anisotropic Terahertz Emission from Bi ₂ Se ₃ Thin Films with Inclined Crystal Planes

Hamh, Sun Young,Park, Soon-Hee,Han, Jeongwoo,Jeon, Jeong Heum,Kahng, Se-Jong,Kim, Sung,Choi, Suk-Ho,Bansal, Namrata,Oh, Seongshik,Park, Joonbum,Kim, Jun Sung,Kim, Jae Myung,Noh, Do Young,Lee, Jong Seo Springer US 2015 NANOSCALE RESEARCH LETTERS Vol.10 No.1

<P>We investigate the surface states of topological insulator (TI) Bi<SUB>2</SUB>Se<SUB>3</SUB> thin films grown on Si nanocrystals and Al<SUB>2</SUB>O<SUB>3</SUB> substrates by using terahertz (THz) emission spectroscopy. Compared to bulk crystalline Bi<SUB>2</SUB>Te<SUB>2</SUB>Se, film TIs exhibit distinct behaviors in the phase and amplitude of emitted THz radiation. In particular, Bi<SUB>2</SUB>Se<SUB>3</SUB> grown on Al<SUB>2</SUB>O<SUB>3</SUB> shows an anisotropic response with a strong modulation of the THz signal in its phase. From x-ray diffraction, we find that the crystal plane of the Bi<SUB>2</SUB>Se<SUB>3</SUB> films is inclined with respect to the plane of the Al<SUB>2</SUB>O<SUB>3</SUB> substrate by about 0.27°. This structural anisotropy affects the dynamics of photocarriers and hence leads to the observed anisotropic response in the THz emission. Such relevance demonstrates that THz emission spectroscopy can be a sensitive tool to investigate the fine details of the surface crystallography and electrostatics of thin film TIs.</P>

Multidimensional effects of biologically synthesized silver nanoparticles in <i>Helicobacter pylori</i> , <i>Helicobacter felis</i> , and human lung (L132) and lung carcinoma A549 cells

Gurunathan, Sangiliyandi,Jeong, Jae-Kyo,Han, Jae Woong,Zhang, Xi-Feng,Park, Jung Hyun,Kim, Jin-Hoi Springer US 2015 NANOSCALE RESEARCH LETTERS Vol.10 No.1

<P>Silver nanoparticles (AgNPs) are prominent group of nanomaterials and are recognized for their diverse applications in various health sectors. This study aimed to synthesize the AgNPs using the leaf extract of <I>Artemisia princeps</I> as a bio-reductant. Furthermore, we evaluated the multidimensional effect of the biologically synthesized AgNPs in <I>Helicobacter pylori</I>, <I>Helicobacter felis</I>, and human lung (L132) and lung carcinoma (A549) cells. UV-visible (UV–vis) spectroscopy confirmed the synthesis of AgNPs. X-ray diffraction (XRD) indicated that the AgNPs are specifically indexed to a crystal structure. The results from Fourier transform infrared spectroscopy (FTIR) indicate that biomolecules are involved in the synthesis and stabilization of AgNPs. Dynamic light scattering (DLS) studies showed the average size distribution of the particle between 10 and 40 nm, and transmission electron microscopy (TEM) confirmed that the AgNPs were significantly well separated and spherical with an average size of 20 nm. AgNPs caused dose-dependent decrease in cell viability and biofilm formation and increase in reactive oxygen species (ROS) generation and DNA fragmentation in <I>H. pylori</I> and <I>H. felis</I>. Furthermore, AgNPs induced mitochondrial-mediated apoptosis in A549 cells; conversely, AgNPs had no significant effects on L132 cells. The results from this study suggest that AgNPs could cause cell-specific apoptosis in mammalian cells. Our findings demonstrate that this environmentally friendly method for the synthesis of AgNPs and that the prepared AgNPs have multidimensional effects such as anti-bacterial and anti-biofilm activity against <I>H. pylori</I> and <I>H. felis</I> and also cytotoxic effects against human cancer cells. This report describes comprehensively the effects of AgNPs on bacteria and mammalian cells. We believe that biologically synthesized AgNPs will open a new avenue towards various biotechnological and biomedical applications in the near future.</P>