Electrically Actuatable Smart Nanoporous Membrane for Pulsatile Drug Release

Jeon, Gumhye,Yang, Seung Yun,Byun, Jinseok,Kim, Jin Kon American Chemical Society 2011 NANO LETTERS Vol.11 No.3

<P>We report on the fabrication of electrically responsive nanoporous membrane based on polypyrrole doped with dodecylbenzenesulfonate anion (PPy/DBS) that was electropolymerized on the upper part of anodized aluminum oxide membrane. The membrane has regular pore size and very high pore density. Utilizing a large volume change of PPy/DBS depending on electrochemical state, the pore size was acutated electrically. The actuation of the pores was experimentally confirmed by in situ atomic force microscopy and in situ flux measurement. We also demonstrated successfully pulsatile (or on-demand) drug release by using fluorescently labeled protein as a model drug. Because of a fast switching time (less than 10 s) and high flux of the drugs, this membrane could be used for emergency therapy of angina pectoris and migraine, which requires acute and on-demand drug delivery, and hormone-related disease and metabolic syndrome.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2011/nalefd.2011.11.issue-3/nl104329y/production/images/medium/nl-2010-04329y_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl104329y'>ACS Electronic Supporting Info</A></P>

Free-Standing Polyimide Nanotips on Substrates for Preparation of Hollow TiO2 Nanotips.

Jeon, Gumhye,Jung, Jinmu,Lee, Seunghyun,Seong, Keum-Yong,Hwang, Dae Youn,Kwon, Hyeog Soong,Kim, Byoung Chul,Kim, Joo Man,Kim, Jin Kon,Yang, Seung Yun American Scientific Publishers 2015 Journal of nanoscience and nanotechnology Vol.15 No.7

<P>We report a facile method to fabricate free-standing polyimide (PI) nanotips on substrates by using plasma treatment with oxygen gas. The PI nanotips were prepared from the self-organization of unetchable materials deposited on a PI film during the plasma treatment. This approach provides a single-step process for the preparation of polymer nanotips in a large area (>inch scale). Furthermore, a selective patterning of the PI nanotips in a specific area was achieved by using a shadow mask. Due to excellent thermal resistance of PI, the PI nanotips maintained structural integrity at high temperature (~ 300 °C). To demonstrate potential application of PI nanotips as a template for hollow nanostructures, hollow TiO2 nanotips were prepared after atomic layer deposition of TiO2 followed by the burning of PI layer.</P>

Hierarchically Self-Organized Monolithic Nanoporous Membrane for Excellent Virus Enrichment

Jeon, Gumhye,Jee, Minhyeok,Yang, Seung Yun,Lee, Bom-yi,Jang, Sung Key,Kim, Jin Kon American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.2

<P>Enrichment of viruses is essential for making high dose viral stocks for vaccines and virus-related research. Since the widely used ultracentrifugation for concentrating viral stock requires ultra-high speed rotation, it easily destroys the activity of some viruses, for instance, hepatitis c virus (HCV), which has a fragile structure and low virus titer. We introduce a novel method to concentrate HCV virus in stock by using a hierarchically self-organized monolithic nanoporous membrane made by stepwise anodization. The pores at the top part of the membrane have very regular sizes that are suitable for the perfect filtration of the virus particles in the stock. On the other hand, the remaining part has large pores that maintain high flux and mechanical strength of the membrane under the high pressure (up to 10 bar). The enrichment efficiency of HCV in crude stocks by using the membrane became over 91%, which is four times higher than that (∼22%) obtained by conventionally used centrifugation. A very high efficiency results from the perfect filtration and no damage to the virion particles during the enrichment process, whereas significant damage to the HCV occurs during centrifugation. The hierarchically self-organized monolithic nanoporous membrane could be effectively employed for concentrating various fragile viruses in stocks, for instance, rabies virus and human immunodeficiency virus in addition to HCV virus.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-2/am4049404/production/images/medium/am-2013-049404_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am4049404'>ACS Electronic Supporting Info</A></P>

Functional nanoporous membranes for drug delivery

Jeon, Gumhye,Yang, Seung Yun,Kim, Jin Kon The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.30

<P>This feature article reviews controlled drug release based on nanoporous membranes for potential medical applications. First, we describe the preparations of nanoporous membranes by top-down and bottom-up methods, and the combination of the two. Then, sustained long-term drug delivery and stimuli-responsive drug delivery by utilizing the nanoporous membranes are explained. The drug delivery system using nanoporous membranes can be used for a new therapy of various diseases through patient-customized medical treatment.</P> <P>Graphic Abstract</P><P>This feature article highlights the up-to-date fabrication of nanoporous membranes and their potential biomedical applications for drug delivery systems. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm32430j'> </P>

A high density array of free standing alumina nanotubes aligned vertically on solid substrates in a large area

Yang, Seung Yun,Jeon, Gumhye,Kim, Jin Kon The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.43

<P>We report an innovative fabrication of a high density array of free standing alumina nanotubes (ANTs) aligned vertically on substrates. A nanoporous polyimide (PI) template was first prepared by dry etching with the aid of an anodized aluminum oxide (AAO) membrane mask followed by atomic layer deposition (ALD) of alumina. ANTs with various diameters, lengths, and wall thicknesses were obtained by controlling the pore size, the thickness of the nanoporous PI template, and the deposition thickness of alumina through ALD, respectively. Optical properties of an ANT array were also tuned by changing the wall thickness of ANTs, and an ANT array on a glass showed excellent antireflectance with less than 0.1% reflectance at a visible wavelength. The nanoporous polymer template fabricated in this study could also be used to obtain a high density array of various inorganic nanotubes with uniform wall thickness and length in a large area. It also enables on-demand patterning of the nanotube array.</P> <P>Graphic Abstract</P><P>A free standing and isolated alumina nanotube array on substrates for tunable antireflective layers. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm34459a'> </P>

Arrangement of Block Copolymer Microdomains Confined inside Hemispherical Cavities

Bae, Dusik,Jeon, Gumhye,Jinnai, Hiroshi,Huh, June,Kim, Jin Kon American Chemical Society 2013 Macromolecules Vol.46 No.13

<P>We investigated, via scanning and transmission electron microscopy, the arrangement of the microdomains of symmetric polystyrene-<I>block</I>-poly(methyl methacrylate) copolymer (PS-<I>b</I>-PMMA) confined in hemispherical cavities. The hemispherical cavities were prepared by using anodic aluminum oxide (AAO) template, where the inner surface of the cavities was modified by thin brush layers of PS, PMMA, and PS-<I>ran</I>-PMMA copolymer. When the inner surface of the cavity is strongly selective to PS chains, concentric rings consisting of PS and PMMA microdomains are formed, replicating the confined geometry of hemisphere. However, as the selectivity of a brush to PS chains becomes weaker, various interesting morphologies are formed that have not been reported in the literature. The experimentally observed microdomain arrangement confined inside the hemispherical cavities was compared with the simulation results based on the dynamic Metropolis Monte Carlo method.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2013/mamobx.2013.46.issue-13/ma4009324/production/images/medium/ma-2013-009324_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ma4009324'>ACS Electronic Supporting Info</A></P>

High Density Silver Accordion Nanostructure for Ultra-Sensitive SERS Substrate

Mooseong Kim,Dusik Bae,Gumhye Jeon,Seungkyu Park,Beomjin Park,Sanghoon Kim,Jin Kon Kim 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

High aspect ratio cylindrical microdomains oriented vertically on the substrate using block copolymer micelles and temperature-programmed solvent vapor annealing

Kim, Sungnam,Jeon, Gumhye,Heo, Sung Woo,Kim, Hye Jeong,Kim, Seung Bin,Chang, Taihyun,Kim, Jin Kon The Royal Society of Chemistry 2013 Soft matter Vol.9 No.23

<P>We report a novel, yet simple, method for the preparation of high aspect ratio cylindrical microdomains oriented vertically on a substrate by using block copolymer micelles and temperature-programmed solvent vapor annealing. Multilayered spherical micelles were first prepared by spin-coating of polystyrene-<I>block</I>-poly(4-vinylpyridine) copolymer (PS-<I>b</I>-P4VP) in toluene solution on a silicon wafer. When temperature-programmed solvent vapor annealing was performed, the spherical micelle cores consisting of P4VP chains were transformed into vertically oriented cylindrical microdomains spanning the entire film thickness up to 550 nm corresponding to the aspect ratio of 15.2. Since nitrogen in the P4VP block could be easily coordinated with many metal precursors, we also fabricated a high density array of gold nanoparticle/polymer nanocomposite nanorods oriented vertically on the substrate.</P> <P>Graphic Abstract</P><P>High aspect ratio cylindrical microdomains oriented vertically on a substrate were prepared using block copolymer micelles and temperature-ramp solvent vapor annealing. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3sm27734h'> </P>

Hierarchically Well-Ordered Array of Concentric Silver Nanorings for Highly Sensitive Surface-Enhanced Raman Scattering Substrate

Bae, Dusik,Cho, Won Joon,Jeon, Gumhye,Byun, Jinseok,Kim, Jin Kon American Chemical Society 2012 The Journal of Physical Chemistry Part C Vol.116 No.50

<P>We fabricated a high density array of concentric silver nanorings in a large area (over in.<SUP>2</SUP>) with uniform gap distance by utilizing half onion-shaped microdomains prepared by symmetric polystyrene-<I>block</I>-poly(methyl methacrylate) copolymers (PS-<I>b</I>-PMMA) confined within hemispherical cavities in anodized aluminum oxide (AAO) template. Silver nanoparticles with 6 nm height were selectively deposited only on the PS microdomains by thermal evaporation. The gap distance of two neighboring silver nanorings was controlled from 12 to 24 nm by changing the total molecular weight of PS-<I>b</I>-PMMAs. The substrate showed high surface-enhanced Raman scattering (SERS) enhancement factor as high as 4.3 × 10<SUP>7</SUP> with good reproducibility (±7%). It could be used for biosensing, detection of trace-level explosive and hazardous chemicals, and reaction monitoring.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2012/jpccck.2012.116.issue-50/jp309008c/production/images/medium/jp-2012-09008c_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp309008c'>ACS Electronic Supporting Info</A></P>

Bioinspired Dual Stimuli-Responsive Membranous System with Multiple On–Off Gates

Lee, Bom-yi,Hyun, Seung,Jeon, Gumhye,Kim, Eun Young,Kim, Jinhwan,Kim, Won Jong,Kim, Jin Kon American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.18

<P>Stimuli-responsive polymers have been widely used for controlled release of several biomolecules. In general, a single stimulus among various stimuli, for instance, temperature, pH, or light, has been used for these polymers. Although some stimuli are applied together, one cannot control each stimulus independently at a given stimulus-responsive polymer. However, to mimic biological system like cell membrane, multiple on off gates utilizing independent control of dual (or multiple) stimuli should be used. Here, we introduce a stimuli-responsive membrane controlled by two orthogonal stimuli. For this purpose, the top and the bottom parts of anodized aluminum oxide membrane walls are independently grafted by thermoresponsive poly(N-isopropylacrylamide) and pH-responsive poly(acrylic acid), respectively, by using surface-initiated atom transfer radical polymerization. The membrane clearly showed two independent on off gates depending on temperature and pH. Furthermore, through light irradiation of two different wavelengths (near-infrared and ultraviolet), temperature and pH were also controlled independently and promptly. Thus, this membrane shows two independent on-off gating of the transport of a model biomolecule of fluorescein isothiocyanate-labeled bovine serum albumin. This strategy suggests the potential of independently modified membrane in layers as stimuli-responsive on off gates for the application of artificial cell membrane.</P>