Publications by authors named "Gibaek Lee"

26 Publications

  • Page 1 of 1

High-Defect-Density Graphite for Superior-Performance Aluminum-Ion Batteries with Ultra-Fast Charging and Stable Long Life.

Nanomicro Lett 2021 Aug 9;13(1):171. Epub 2021 Aug 9.

Advanced Energy Materials Design Lab, School of Chemical Engineering, Yeungnam University, Gyeongsan, 38541, Republic of Korea.

Rechargeable aluminum-ion batteries (AIBs) are a new generation of low-cost and large-scale electrical energy storage systems. However, AIBs suffer from a lack of reliable cathode materials with insufficient intercalation sites, poor ion-conducting channels, and poor diffusion dynamics of large chloroaluminate anions (AlCl and AlCl). To address these issues, surface-modified graphitic carbon materials [i.e., acid-treated expanded graphite (AEG) and base-etched graphite (BEG)] are developed as novel cathode materials for ultra-fast chargeable AIBs. AEG has more turbostratically ordered structure covered with abundant micro- to nano-sized pores on the surface structure and expanded interlayer distance (d = 0.3371 nm) realized by surface treatment of pristine graphite with acidic media, which can be accelerated the diffusion dynamics and efficient AlCl ions (de)-intercalation kinetics. The AIB system employing AEG exhibits a specific capacity of 88.6 mAh g (4 A g) and ~ 80 mAh g at an ultra-high current rate of 10 A g (~ 99.1% over 10,000 cycles). BEG treated with KOH solution possesses the turbostratically disordered structure with high density of defective sites and largely expanded d-spacing (d = 0.3384 nm) for attracting and uptaking more AlCl ions with relatively shorter penetration depth. Impressively, the AIB system based on the BEG cathode delivers a high specific capacity of 110 mAh g (4 A g) and ~ 91 mAh g (~ 99.9% over 10,000 cycles at 10 A g). Moreover, the BEG cell has high energy and power densities of 247 Wh kg and 44.5 kW kg. This performance is one of the best among the AIB graphitic carbon materials reported for chloroaluminate anions storage performance. This finding provides great significance for the further development of rechargeable AIBs with high energy, high power density, and exceptionally long life.
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http://dx.doi.org/10.1007/s40820-021-00698-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8353050PMC
August 2021

Fast charging with high capacity for aluminum rechargeable batteries using organic additive in an ionic liquid electrolyte.

Phys Chem Chem Phys 2020 Dec;22(47):27525-27528

Materials and Electrochemistry Lab., Department of Chemical Engineering, Inha University, Incheon 22212, Republic of Korea.

Aluminum-ion batteries have many advantages such as the natural abundance of aluminum, high theoretical capacity, and low cost. However, the ionic liquid commonly used as the electrolyte for aluminum-ion batteries has high viscosity, which hinders the migration of charge carriers. In this study, we used various organic solvents as additives for the ionic liquid electrolyte and investigated their effect on the battery performance. The electrolyte containing 45% (v/v) benzene had the best electrochemical properties, which led to a high specific capacity of 90 mA h g-1 at an extremely high current density of 5 A g-1.
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http://dx.doi.org/10.1039/d0cp05050dDOI Listing
December 2020

NIR-vis-Induced pH-Sensitive TiO Immobilized Carbon Dot for Controllable Membrane-Nuclei Targeting and Photothermal Therapy of Cancer Cells.

ACS Appl Mater Interfaces 2020 Aug 12;12(34):37929-37942. Epub 2020 Aug 12.

Department of Green Bio Engineering, Korea National University of Transportation, Chungju 380-702, Republic of Korea.

This study investigated a selective and sensitive theragnosis system for the specific targeting of the membrane and nuclei based on visible-light and pH-responsive TiO-integrated cross-linked carbon dot (C-CD/TiO) for tumor detection and controllable photothermal therapy. The cross-linking system was formed by boronate ester linkages between the TiO-immobilized Dopa-decyl (D-CD) and zwitterionic-formed CD (Z-CD) for nuclear targeting, which showed fluorescence "off" at physiological pH. The fluorescence recovered to the "on" state in acidic cancer cells owing to cleavages of the boronate ester bonds, resulting in the disruption of the Förster resonance energy transfer that generated different CDs useful for tumor-selective biosensors and therapy. D-CD, which is hydrophobic, can penetrate the hydrophobic sites of the cell membrane; it caused a loss in the hydrophobicity of these sites after visible-light irradiation. This was achieved by the photocatalytic activity of the TiO modulating energy bandgap, whereas the Z-CD targeted the nucleus, as confirmed by merged confocal microscopy images. D-CD augmented by photothermal heat also exhibited selective anticancer activity in the acidic tumor condition but showed only minimal effects at a normal site at pH 7.4. After C-CD/TiO injection to an tumor model, C-CD/TiO efficiently ablated tumors under NIR light irradiation. The C-CD/TiO group showed up-regulation of the pro-apoptotic markers such as and in tumor. This material exhibited its potential as a theragnostic sensor with excellent biocompatibility, high sensitivity, selective imaging, and direct anticancer activity via photothermal therapy.
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http://dx.doi.org/10.1021/acsami.0c11979DOI Listing
August 2020

Nitrogen-doped TiO(B) nanobelts enabling enhancement of electronic conductivity and efficiency of lithium-ion storage.

Nanotechnology 2020 Oct 24;31(41):415401. Epub 2020 Jun 24.

Advanced Energy Materials Design Lab, School of Chemical Engineering, Yeungnam University, Gyeongsan-Si 38541 Republic of Korea.

To enhance the intrinsic electrical conductivities of TiO(B) nanobelts, nitrogen(N)-doped TiO(B) nanobelts (N-TNB) were prepared in this study by a facile and cost-effective hydrothermal method using urea as the nitrogen source with TiO (P25) nanoparticles. x-ray photoelectron spectroscopy confirmed that the N-atoms preferentially occupied up to ∼0.516 atom% in the interstitial sites of the N-TNB and the maximum concentration of substituted-N bonds in the N-TNB was ∼0.154 atom%, thereby the total concentration of doped nitrogen elements of ∼0.67 atom% improved the high intrinsic electrical conductivity and ionic diffusivity of the TiO(B) nanobelts. The as-prepared N-TNB electrode delivered the highest specific capacity of 133.9 mAh g in the first cycle, with an exceptional cyclic capacity retention at an ultrafast current rate of 1000 mA g; this is not less than 51% after 500 cycles and represents an excellent rate capability of ∼37 mAh g at an ultra-high rate of 40 C. These values are among the best ever reported on comparison of the delivered highest discharge capacity of N-TNB at 1000 mA g and high-rate capabilities of its Li ion storage with the literature data for N-TNB (∼231.5 mAh g at a very low current density of 16.75 mA g, ∼0.1 C) of similar materials used in sodium-ion batteries. This implies the potential feasibility of these N-TNB as high-capacity anode materials for next-generation, high-energy-density, electrochemical energy-storage devices.
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http://dx.doi.org/10.1088/1361-6528/ab9fb6DOI Listing
October 2020

Diselenide-Bridged Carbon-Dot-Mediated Self-Healing, Conductive, and Adhesive Wireless Hydrogel Sensors for Label-Free Breast Cancer Detection.

ACS Nano 2020 07 12;14(7):8409-8420. Epub 2020 Jun 12.

Department of Chemical & Biological Engineering, Korea National University of Transportation, Chungju 380-702, Republic of Korea.

Recently, a great deal of research has focused on the study of self-healing hydrogels possessing electronic conductivity due to their wide applicability for use in biosensors, bioelectronics, and energy storage. The low solubility, poor biocompatibility, and lack of effective stimuli-responsive properties of their sp carbon-rich hybrid organic polymers, however, have proven challenging for their use in electroconductive self-healing hydrogel fabrication. In this study, we developed stimuli-responsive electrochemical wireless hydrogel biosensors using ureidopyriminone-conjugated gelatin (Gel-UPy) hydrogels that incorporate diselenide-containing carbon dots (dsCD) for cancer detection. The cleavage of diselenide groups of the dsCD within the hydrogels by glutathione (GSH) or reactive oxygen species (ROS) initiates the formation of hydrogen bonds that affect the self-healing ability, conductivity, and adhesiveness of the Gel-UPy/dsCD hydrogels. The Gel-UPy/dsCD hydrogels demonstrate more rapid healing under tumor conditions (MDA-MB-231) compared to that observed under physiological conditions (MDCK). Additionally, the cleavage of diselenide bonds affects the electrochemical signals due to the degradation of dsCD. The hydrogels also exhibit excellent adhesiveness and cancer detection ability after exposure to a high concentration of GSH or ROS, and this is comparable to results observed in a low concentration environment. Based on the combined self-healing, conductivity, and adhesiveness properties of the Gel-UPy/dsCD, this hydrogel exhibits promise for use in biomedical applications, particularly those that involve cancer detection, due to its selectivity and sensitivity under tumor conditions.
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http://dx.doi.org/10.1021/acsnano.0c02517DOI Listing
July 2020

One-dimensional hierarchical nanostructures of NiCoO, NiCoS and NiCoSe with superior electrocatalytic activities toward efficient oxygen evolution reaction.

Nanotechnology 2020 May 3;31(29):295405. Epub 2020 Apr 3.

Advanced Energy Materials Design Lab, School of Chemical Engineering, Yeungnam University, 38541 Gyeongsan, Republic of Korea.

Oxygen evolution reaction (OER), a sluggish multistep process in electrochemical water splitting, is still a challenging issue to achieve with cheap, earth-abundant non-precious and non-polluting materials. In this work, three different electrocatalysts, specifically NiCoO, NiCo S, and NiCo Se synthesized by simple hydrothermal process, show excellent OER activity. This report not only projects OER performances but also demonstrates a modified method for the transformation of NiCoO to NiCo S and NiCo Se via sulfidation and selenization reactions. The well crystalline, porous nature of NiCoO, NiCo S, and NiCoSe electrocatalysts with one dimensional (1D) structural morphology affords overpotentials of 346 mV, 309 mV and 270 mV at current density of 10 mA cm in 1 M KOH. In particular, NiCoSe exhibits a low overpotential as well as a smaller Tafel slope of 63 mV dec, leading to robust stability in alkaline conditions. The abundant active sites, large mass and size of NiCoSe enhances the performance of the OER. This type of selenide-based material with low toxicity is also an advantage for eco-friendly applications.
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http://dx.doi.org/10.1088/1361-6528/ab8667DOI Listing
May 2020

Reduction-Triggered Paclitaxel Release Nano-Hybrid System Based on Core-Crosslinked Polymer Dots with a pH-Responsive Shell-Cleavable Colorimetric Biosensor.

Int J Mol Sci 2019 Oct 28;20(21). Epub 2019 Oct 28.

Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 380-702, Korea.

Herein, we describe the fabrication and characterization of carbonized disulfide core-crosslinked polymer dots with pH-cleavable colorimetric nanosensors, based on diol dye-conjugated fluorescent polymer dots (L-PD), for reduction-triggered paclitaxel (PTX) release during fluorescence imaging-guided chemotherapy of tumors. L-PD were loaded with PTX (PTX loaded L-PD), via π-π stackings or hydrophobic interactions, for selective theragnosis by enhanced release of PTX after the cleavage of disulfide bonds by high concentration of glutathione (GSH) in a tumor. The nano-hybrid system showed fluorescence quenching behavior with less than 2% of PTX released under physiological conditions. However, in a tumor microenvironment, the fluorescence recovered at an acidic-pH, and PTX (approximately 100% of the drug release) was released efficiently out of the matrix by reduction caused by the GSH level in the tumor cells, which improved the effectiveness of the cancer treatment. Therefore, the colorimetric nanosensor showed promising potential in distinguishing between normal and cancerous tissues depending on the surrounding pH and GSH concentrations so that PTX can be selectively delivered into cancer cells for improved cancer diagnosis and chemotherapy.
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http://dx.doi.org/10.3390/ijms20215368DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6862247PMC
October 2019

Nb-doped TiO support with enhanced durability as a cathode for polymer electrolyte membrane fuel cells.

Nanotechnology 2020 Jan 2;31(3):03LT01. Epub 2019 Oct 2.

Materials and Electrochemistry Lab., Department of Chemical Engineering, Inha University, 22212 Incheon, Republic of Korea.

Stability is one of the key requirements of electrocatalyst support materials for polymer electrolyte membrane fuel cells. To develop a highly stable Pt catalyst support material, in this work, we have synthesized Nb-doped TiO electrocatalyst supports. The amount of Nb dopant is measured using inductively coupled plasma mass spectrometry, while the characteristics of the as-prepared Nb-doped TiO supports are analyzed by transmission electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. Durability experiments are conducted by high potential cycling using the as-prepared Pt/TiO-Nb materials; half-cell cyclic voltammetry and single-cell performance measurements reveal that Pt/TiO-Nb shows superior durability and corrosion resistance with a degradation rate of only 20% while the performance of commercial Pt/C support decreased 55%.
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http://dx.doi.org/10.1088/1361-6528/ab4a3fDOI Listing
January 2020

RGO-Coated TiO Microcones for High-Rate Lithium-Ion Batteries.

ACS Omega 2018 Aug 30;3(8):10205-10210. Epub 2018 Aug 30.

Department of Chemistry and Chemical Engineering, Inha University, 22212 Incheon, South Korea.

Reduced graphene oxide (RGO)-coated TiO microcones have been synthesized via simple anodization and cyclic voltammetry for use in lithium-ion batteries (LIBs). Microcones had a perpendicularly oriented hollow core, an anatase structure, and a high surface area, allowing higher capacity than other nanosized TiO structures. TiO has low electrical conductivity, leading to the limitation of fast charging and high capacity; however, this was improved by the application of an RGO coating in this work. As anode materials of LIB, the obtained RGO microcone showed a capacity of 157 mAh g at 10C (fully charged within ∼360 s) and sustained 1000 cycles with only 0.02% capacity fading per cycle. The capacity was 1.5 times higher than that of conventional microcone. We speculated that the decrease in the charge-transfer resistance ( ) played a crucial role in increasing the capacity with fast charging.
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http://dx.doi.org/10.1021/acsomega.8b00926DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6644754PMC
August 2018

Zwitterionic carbon dot-encapsulating pH-responsive mesoporous silica nanoparticles for NIR light-triggered photothermal therapy through pH-controllable release.

Biomater Sci 2019 May;7(6):2600-2610

Department of IT Convergence, Korea National University of Transportation, Chungju 380-702, Republic of Korea.

Here, we designed a pH-responsive Indocyanine Green (ICG)-loaded zwitterion fluorescent carbon dot (CD)-encapsulating mesoporous silica nanoparticle (MSN) for pH-tunable image-guided photothermal therapy. ICG was loaded into MSN(CD) via hydrophobic and electrostatic interactions between zwitterionic CDs and ICG to achieve a controlled photothermal temperature with a fluorescent "off/on" system. The porosity of the MSNs was altered after ICG loading because of intermolecular interactions between the CDs and ICG inside the MSN shell and core, which blocked the MSN pore. The acidic environment pH affected the fluorescent signals of the ICG-MSN(CD), reflecting the "off-on" characteristics of the synthesized MSN, which then induced the release of ICG from the matrices. Moreover, the photothermal conversion of ICG-MSN(CD) showed sufficient heat generation to kill cancer cells at an acidic pH with low-temperature elevation at physiological pH. ICG-MSN(CD) demonstrated good cell viability of MDA-MB-231 cells without irradiation; however, high necrosis was observed when the environment was adjusted to acidic pH and after near-infrared irradiation. These pH-responsive photothermal mesoporous silica nanoparticles may have applications in biomedicine, particularly for cancer treatment.
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http://dx.doi.org/10.1039/c9bm00160cDOI Listing
May 2019

In situ durability of various carbon supports against carbon corrosion during fuel starvation in a PEM fuel cell cathode.

Nanotechnology 2019 Feb 28;30(8):085402. Epub 2018 Nov 28.

Advanced Energy Materials Design Lab., School of Chemical Engineering, Yeungnam University, 38541 Gyeongsan, Republic of Korea.

In this study, the degradation of different cathode carbon supports is investigated in proton exchange membrane fuel cells (PEMFCs). A platinum catalyst is synthesized using various carbon supports, such as Vulcan XC-72, graphite nanopowder and carbon nanotube, which are evaluated based on the fabrication of membrane electrode assemblies. During the startup and shutdown of PEMFCs, the individual electrode potential can be measured in situ using a dynamic hydrogen electrode. The cathode potential increases instantaneously to 1.4 V in one attempt, when H/air boundaries are developed on the anode side during the fuel starvation, leading to significant carbon corrosion. The corrosion rates of various carbon supports are calculated from the concentration of gases, such as CO, CO and SO, emitted from the cathode outlet, measured directly in situ by Fourier transform infrared gas analysis. The carbon nanotube-supported Pt catalyst shows the best performance against carbon corrosion during fuel starvation, compared to commercial Pt/C catalyst and other types of carbon supports.
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http://dx.doi.org/10.1088/1361-6528/aaf48cDOI Listing
February 2019

Fast-Charging and High Volumetric Capacity Anode Based on Co O /[email protected] Composites for Lithium-Ion Batteries.

Chemistry 2018 Dec 15;24(71):19045-19052. Epub 2018 Nov 15.

Nano & Energy Materials Laboratory, Department of Chemistry and Chemical Engineering, Inha University, 22212, Incheon, Republic of Korea.

This paper presents an investigation of anodic TiO nanotube arrays (TNAs), with a Co O /CuO coating, for lithium-ion batteries (LIBs). The coated TNAs are investigated using various analytical techniques, with the results clearly suggesting that the molar ratio of Co O /CuO in the TiO nanotubes substantially influences its battery performance. In particular, a cobalt/copper molar ratio of 2:1 on the TNAs (Co Cu @TNAs) features the best LIBs anode performance, exhibiting high reversible capacity and enhanced cycling stability. Noticeably, Co Cu @TNAs achieve excellent rate capability even after quite a high current density of 20.0 A g (≈25 C, where C corresponds to complete discharge in 1 h) and superior volumetric reversible capacity of ≈3330 mA h  cm . This value is approximately seven times higher than those of a graphite-based anode. This outstanding performance is attributed to the synergistic effects of Co Cu @TNAs: 1) the structural advantage of TNAs, with their large amount of free space to accommodate the large volume expansion during Li insertion/extraction and 2) the optimized ratio of Co O and CuO in the composite for improved capacity. In addition, no binder or conductive agent is used, which is partly responsible for the overall improved volumetric capacity and electrochemical performance.
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http://dx.doi.org/10.1002/chem.201804313DOI Listing
December 2018

Redox-responsive FRET-based polymer dot with BODIPY for fluorescence imaging-guided chemotherapy of tumor.

Eur J Pharm Biopharm 2018 Nov 26;132:200-210. Epub 2018 Sep 26.

Department of IT Convergence, Korea National University of Transportation, Chungju 380-702, Republic of Korea; Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 380-702, Republic of Korea. Electronic address:

Redox-responsive polymer dot (PD) were synthesized from disulfide cross-linked polymers in a carbonized process to allow quenching effects by loading of boron-dipyrromethene (BODIPY) onto the matrix. The disulfide linkage facilitated degradation of the PD system by intracellular glutathione (GSH), leading to fluorescence recovery by BODIPY and intracellular drug release. The paclitaxel release profile showed that approximately 100% of the drug escaped from the matrix in response to 10 mM GSH, whereas less than 10% was released in the absence of GSH. In vitro studies showed that quenching produced by BODIPY loading enabled visual monitoring of cancer cell death, as the quenching disappeared when BODIPY was released by GSH inside of cancer cells. The PD contain disulfide bonds representing a GSH-triggered ligand; thus, nanocarriers presented enhanced in vivo chemotherapeutic inhibition in xenograft tumor-bearing mice localized at the cancer location, guided by fluorescent off-on system tracking and measured by the release of BODIPY. This platform reacts to the redox level in sensitive manner and cancer cell death can be monitored by fluorescence, making this platform useful for bio-applications, particularly in vitro and in vivo therapy and diagnosis, while considering the cell physiological environment. This system may be useful for wider medical applications.
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http://dx.doi.org/10.1016/j.ejpb.2018.09.025DOI Listing
November 2018

Boronate-based fluorescent carbon dot for rapid and selectively bacterial sensing by luminescence off/on system.

J Pharm Biomed Anal 2018 Sep 23;159:1-10. Epub 2018 Jun 23.

Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 380-702, Republic of Korea; Department of IT Convergence, Korea National University of Transportation, Chungju 380-702, Republic of Korea. Electronic address:

Boronic acid, which can bind chemo-selectively and reversibly to diols, could be used for the early detection of bacteria through its affinity-binding reaction with diol groups on the bacterial cell wall. Herein, we describe the use of a diol-modified fluorescent probe (DYE) conjugated to a nanosensor consisting of phenylboronic acid-functionalized fluorescent carbon dot (FCD) to allow quenching via the Förster resonance energy transfer (FRET) process. Phenylboronic acid is well-known for its preferential affinity for diol-containing molecules through cyclic ester bond formation. Therefore, in the presence of glucose-containing bacteria, the DYE in the cyclic ester form will be released from the FCD and replaced by the bacterial cell forming a new cyclic boronate ester bond with the nanoparticle, inducing recovery of the fluorescence. Quantitatively, the system's detection performance at various bacterial concentrations (10-10 CFU/mL) reached ∼100% after 60 min, indicating that the high binding affinity of the diol moeity on the peptidoglycan (sugar)-rich bacteria was enough to displace the DYE from the boronic acid-functionalized FCD platform. Our facile and tunable fluorescence switch-on system was tested for its ability to detect bacteria in water from a contaminated river. Incredibly, the system was most successful in detecting bacteria in the contaminated river water, thus proving it to be a less expensive and more robust affinity biosensor for the detection of contaminating pathogens in various chemoselective ligand-based environments.
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http://dx.doi.org/10.1016/j.jpba.2018.06.043DOI Listing
September 2018

Hypostatic instability of aluminum anode in acidic ionic liquid for aluminum-ion battery.

Nanotechnology 2018 Sep 19;29(36):36LT01. Epub 2018 Jun 19.

Materials and Electrochemistry Lab., Department of Chemical Engineering, Inha University, 22212 Incheon, Republic of Korea.

Aluminum-ion batteries are considered to be a promising post lithium-ion battery system in energy storage devices because aluminum is earth-abundant, has a high theoretical capacity, and is of low cost. We report on the chemical activities and stabilities of chloroaluminate anions [Al Cl ] with aluminum metal using a different mole ratio of AlCl and 1-ethyl-3-methylimidazolium chloride. The morphological changes in the Al metal surface are investigated as a function of dipping time in electrolyte, revealing that the Al metal surface is locally attacked by chloroaluminate anions followed by the formation of a new Al oxide layer with a specific lattice plane and a craterlike surface around the cracking site. The aluminum-ion battery exhibits outstanding cycle life and capacity even at the high C-rate of 3 A g, with a high energy efficiency of 98%, regardless of the differences in the size of chloroaluminate anions.
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http://dx.doi.org/10.1088/1361-6528/aacd7fDOI Listing
September 2018

Target-specific induced hyaluronic acid decorated silica fluorescent [email protected] for bio-imaging guided near-infrared photothermal therapy.

J Mater Chem B 2017 Sep 17;5(34):7099-7108. Epub 2017 Aug 17.

Department of IT Convergence, Korea National University of Transportation, Chungju 380-702, Republic of Korea.

We describe a novel synthesis method for silica nanoparticles, which involves a combination of these nanoparticles with targetable and nontargetable fluorescent dopamine-conjugated hyaluronic acid (HA-DA) via rational chemical dehydration. The resulting HA-decorated silica fluorescent nanoparticles, electrostatically linked to polyaniline (PANI) to form ionic complexes, possessed high fluorescence intensity and were monodisperse in solution, near-infrared light responsive, and amenable to specific labeling of cancer cell lines. When exposed to near-infrared irradiation, the fluorescent silica nanoparticles exerted photothermal cytotoxicity guided by bioimaging and distinguished malignant cancer cells from normal cells via receptor CD44. Different heating properties of nanoparticles depend on local interactions between different structures, and determination of their efficacy could lead to new thermal treatment options such as noninvasive photothermal therapy.
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http://dx.doi.org/10.1039/c7tb01606aDOI Listing
September 2017

Electrochemical properties of an aluminum anode in an ionic liquid electrolyte for rechargeable aluminum-ion batteries.

Phys Chem Chem Phys 2017 Mar;19(13):8653-8656

Materials & Electrochemistry Laboratory, Department of Chemical Engineering, Inha University, Incheon 22212, South Korea.

An aluminum metal, both native and with a very thin oxide film, was investigated as an anode for aluminum-ion batteries. Investigations were carried out in an acidic ionic liquid electrolyte, composed of AlCl in 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl), with β-MnO/C as a cathode. The battery based on Al metal with a very thin oxide film showed high capacity and stable surface corrosion.
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http://dx.doi.org/10.1039/c6cp08776kDOI Listing
March 2017

Preparation of dual-responsive hybrid fluorescent nano probe based on graphene oxide and boronic acid/BODIPY-conjugated polymer for cell imaging.

Mater Sci Eng C Mater Biol Appl 2017 Feb 9;71:1064-1071. Epub 2016 Nov 9.

Department of IT Convergence, Korea National University of Transportation, Chungju 380-702, Republic of Korea; Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 380-702, Republic of Korea. Electronic address:

Here, we report a pH- and thermo-responsive fluorescent nanomaterial of functionalized reduced graphene oxide (rGO) with cross-linked polymer produced via catechol-boronate diol binding mechanism. When conjugated with the hydrophobic dye boron dipyrromethane (BODIPY), this material can act as a dual-responsive nanoplatform for cells imaging. 2-Chloro-3',4'-dihydroxyacetophenone (CCDP)-quaternized-poly(dimethylaminoethyl methacrylate-co-N-isopropylacrylamide) [C-PDN] was cross-linked with BODIPY and 4-chlorophenyl boronic acid (BA)-quaternized-poly(ethylene glycol)-g-poly(dimethylaminoethyl methacrylate-co-N-isopropylacrylamide) [BB-PPDN]. The GO was then reduced by the catechol group in the cross-linked polymer to synthesize rGO nanoparticles, which able to stabilize the quenching mechanism. This nanoplatform exhibits intense fluorescence at acidic pH and low fluorescence at physiological pH. Confocal laser scanning microscopy (CLSM) images shows bright fluorescence at lysosomal pH and total quench at physiological pH. Therefore, we have successfully developed a promising sensitive bio-imaging probe for identifying cancer cells.
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http://dx.doi.org/10.1016/j.msec.2016.11.018DOI Listing
February 2017

Detection of Cronobacter sakazakii in powdered infant formula using an immunoliposome-based immunomagnetic concentration and separation assay.

Sci Rep 2016 10 10;6:34721. Epub 2016 Oct 10.

Department of Food Science and Technology, Yeungnam University, 280 Daehak-ro, Gyeongsan-si, Gyeongsangbuk-do 38541, Republic of Korea.

This study aimed to optimize the applicability of an immunoliposome-based immunomagnetic concentration and separation assay to facilitate rapid detection of Cronobacter sakazakii in powdered infant formula (PIF). To determine the detection limit, specificity, and pre-enrichment incubation time (0, 4, 6, and 8 h), assay tests were performed with different cell numbers of C. sakazakii (2 × 10 and 2 × 10 CFU/ml) inoculated in 10 g of PIF. The assay was able to detect as few as 2 cells of C. sakazakii/10 g of PIF sample after 6 h of pre-enrichment incubation with an assay time of 2 h 30 min. The assay was assessed for cross-reactivity with other bacterial strains and exhibited strong specificity to C. sakazakii. Moreover, the assay method was applied to the detection of C. sakazakii in PIF without pre-enrichment steps, and the results were compared with INC-ELISA and RT-PCR. The developed method was able to detect C. sakazakii in spiked PIF without pre-enrichment, whereas INC-ELISA failed to detect C. sakazakii. In addition, when compared with the results obtained with RT-PCR, our developed assay required lesser detection time. The developed assay was also not susceptible to any effect of the food matrix or background contaminant microflora.
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http://dx.doi.org/10.1038/srep34721DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5056387PMC
October 2016

Detection of Cronobacter Genus in Powdered Infant Formula by Enzyme-linked Immunosorbent Assay Using Anti-Cronobacter Antibody.

Front Microbiol 2016 21;7:1124. Epub 2016 Jul 21.

Department of Food Science and Technology, Yeungnam University Gyeongsan, South Korea.

Cronobacter species (Cronobacter spp.) are hazardous foodborne pathogens associated with baby food, powdered infant formula (PIF). To develop a rapid and sensitive method for simultaneous detection of seven Cronobacter spp. in PIF, an indirect non-competitive enzyme-linked immunosorbent assay (INC-ELISA) was developed based on a novel immunoglobulin G (IgG), anti-Cronobacter IgG. The developed INC-ELISA was able to detect seven Cronobacter spp. at concentrations ranging from (5.6 ± 0.30) × 10(3) to (2.1 ± 0.01) × 10(5) colony forming unit (CFU)/mL in pure culture. Further, INC-ELISA employing anti-Cronobacter IgG was applicable for analysis of PIF samples contaminated with less than <10 cells of Cronobacter spp. per 25 g of PIF in 36 h. The developed antibody showed slight cross-reactivity with Franconibacter pulveris (LMG 24057) at high concentration (10(8) CFU/mL). The INC-ELISA method displayed excellent specificity without compromising cross-reactivity with other foodborne pathogens. The INC-ELISA assay method developed in this study using a novel anti-Cronobacter IgG facilitated highly sensitive, efficient, and rapid detection of Cronobacter spp. in baby food.
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http://dx.doi.org/10.3389/fmicb.2016.01124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4955378PMC
August 2016

Immunochromatographic Strip Assay for Detection of in Pure Culture.

J Microbiol Biotechnol 2016 Nov;26(11):1855-1862

Department of Food Science and Technology, Yeungnam University, Gyeongsan 38541, Republic of Korea.

() is a foodborne pathogen, posing a high risk of disease to infants and immunocompromised individuals. In order to develop a quick, easy, and sensitive assay for detecting , a rabbit anti- immunoglobulin G (IgG) was developed using sonicated cell protein from . The developed anti- (IgG) was of good quality and purity, as well as species-specific. The developed rabbit anti- IgG was attached to the surface of a sulforhodamine B-encapsulated liposome to form an immunoliposome. A test strip was then prepared by coating goat anti-rabbit IgG onto the control line and rabbit anti- IgG onto the test line, respectively, of a plastic-backed nitrocellulose membrane. A purple color signal both on the test line and the control line indicated the presence of in the sample, whereas purple color only on the control line indicated the absence of in the sample. This immunochromatographic strip assay could produce results in 15 min with a limit of detection of 10 CFU/ml in culture. The immunochromatographic strip assay also showed very good specificity without cross-reactivity with other tested species. Based on these results, the developed immunochromatographic strip assay is efficient for the detection of and has high potential for on-site detection.
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http://dx.doi.org/10.4014/jmb.1606.06004DOI Listing
November 2016

Highly Ordered TiO2 Microcones with High Rate Performance for Enhanced Lithium-Ion Storage.

ACS Appl Mater Interfaces 2016 Jun 2;8(23):14558-63. Epub 2016 Jun 2.

Nano & Energy Materials Lab, Department of Chemistry and Chemical Engineering, Inha University , Incheon 402-751, South Korea.

The perpendicularly oriented anatase TiO2 microcones for Li-ion battery application were synthesized via anodization of a Ti foil in aqueous HF + H3PO4 solution. The TiO2 microcones exhibited a high active surface area with a hollow core depending on applied voltage and reaction time, confirmed by SEM, XRD and TEM with EDS mapping. Li insertion/desertion into TiO2 microcones was evaluated for the first time in half-cell configuration in terms of various current density and long-term cyclability. The electrochemical experiments demonstrated that the as-prepared TiO2 microcones as anode material exhibited 3 times higher capacity as compared with TiO2 nanotubular structures, excellent rate performance (0.054 mAhcm(-2) even at 50 C) and reliable capacity retention during 500 cycles, which was attributed to facile diffusion of Li-ions induced in hollow anatase TiO2 microcones structure with multilayered nanofragment.
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http://dx.doi.org/10.1021/acsami.6b03099DOI Listing
June 2016

Immunoliposome-based immunomagnetic concentration and separation assay for rapid detection of Cronobacter sakazakii.

Biosens Bioelectron 2016 Mar 28;77:986-94. Epub 2015 Oct 28.

Department of Food Science and Technology, Yeungnam University, 280 Daehak-ro, Gyeongsan-si, Gyeongsangbuk-do 712-749, Republic of Korea. Electronic address:

This study aimed to develop an immunoliposome-based immunomagnetic concentration and separation assay for the rapid detection of Cronobacter sakazakii (C. sakazakii), an acute opportunistic foodborne pathogenic bacterium, in both pure culture and infant formula. To develop the assay, magnetic nanoparticles (diameter 30 nm) were coated with immunoglobulin G (IgG), specifically anti-C. sakazakii IgG, and applied for the sensitive and efficient detection of C. sakazakii using immunoliposomes. The binding efficiency of anti-C. sakazakii IgG to the magnetic nanoparticles was 86.23 ± 0.59%. The assay developed in this study detected as few as 3.3 × 10(3) CFUmL(-1) of C. sakazakii in pure culture within 2h 30 min; in comparison, an indirect non-competitive enzyme-linked immunosorbent assay was able to detect 6.2 × 10(5) CFUmL(-1) of C. sakazakii in pure culture after 17 h. The developed assay did not show any cross-reactivity with other Cronobacter spp. or pathogens belonging to other genera. In addition, the method was able to detect 10(3) CFUmL(-1) of C. sakazakii in infant formula without any pre-incubation. These results confirm that the immunoliposome-based immunomagnetic concentration and separation assay may facilitate highly sensitive, efficient, and rapid detection of C. sakazakii.
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http://dx.doi.org/10.1016/j.bios.2015.10.077DOI Listing
March 2016

Concentration-mediated multicolor fluorescence polymer carbon dots.

Luminescence 2016 May 22;31(3):897-904. Epub 2015 Oct 22.

Department of IT Convergence, Korea National University of Transportation, Chungju, Republic of Korea.

Polymer dots (PDs) showing concentration-mediated multicolor fluorescence were first prepared from sulfuric acid-treated dehydration of Pluronic® F-127 in a single step. Pluronic-based PDs (P-PDs) showed high dispersion stability in solvent media and exhibited a fluorescence emission that was widely tunable from red to blue by adjusting both the excitation wavelengths and the P-PD concentration in an aqueous solution. This unique fluorescence behavior of P-PDs might be a result of cross-talk in the fluorophores of the poly(propylene glycol)-rich core inside the P-PD through either energy transfer or charge transfer. Reconstruction of the surface energy traps of the P-PDs mediated through aggregation may lead to a new generation of carbon-based nanomaterials possessing a fluorescence emission and tunable by adjusting the concentration. These structures may be useful in the design of multifunctional carbon nanomaterials with tunable emission properties according to a variety of internal or external stimuli.
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http://dx.doi.org/10.1002/bio.3050DOI Listing
May 2016

CMOS-compatible metal-stabilized nanostructured Si as anodes for lithium-ion microbatteries.

Nanoscale Res Lett 2014 14;9(1):613. Epub 2014 Nov 14.

Fraunhofer Institute for Mechanics of Materials IWM, Halle (Saale) 06120 Germany ; Department of Physics, Martin-Luther University of Halle-Wittenberg, Halle (Saale) 06099, Germany.

The properties of fully complementary metal-oxide semiconductor (CMOS)-compatible metal-coated nanostructured silicon anodes for Li-ion microbatteries have been studied. The one-dimensional nanowires on black silicon (nb-Si) were prepared by inductively coupled plasma (ICP) etching and the metal (Au and Cu) coatings by successive magnetron sputtering technique. The Cu-coated nb-Si show the most promising electrochemical performance enhancements for the initial specific capacity as well as their cyclability compared to pristine nb-Si. The electrochemical and microstructural properties before and after cycling of the metal-coated nb-Si compared to their pristine counterparts are discussed in detail.
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http://dx.doi.org/10.1186/1556-276X-9-613DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4234740PMC
November 2014

Heparin based nanoparticles for cancer targeting and noninvasive imaging.

Quant Imaging Med Surg 2012 Sep;2(3):219-26

Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungbuk, 380-702 Republic of Korea;

Numerous papers on heparin nanoparticles have been reported regarding targeting therapy and biomedical imaging. Here, we have summarized the prospects and opportunities of heparin as a carrier for cancer targeting and imaging. First, we proposed heparin-anticancer drug conjugates showing higher anticancer activity than free drug. The conjugated heparin (heparin-deoxycholate sodium) retained its ability to bind with angiogenic factors, showing a significant decrease in endothelial tubular formation. Second, targeting ligands conjugated heparin derivatives have introduced for a receptor mediated delivery of anticancer drug. Heparin-folic acid-retinoic acid (HFR) bioconjugates for treating cancer cells showed 3 fold higher efficacy than heparin-retinoic acid (HR). Besides active and passive targeting drug delivery, several papers have been reported regarding delivery of imaging agents by heparin nanoparticles. Finally, this research highlight has covered imaging agents such as gold nanoparticles and quantum dots (QDs) for noninvasive biomedical imaging. Very recently our group demonstrated that semiconductor QDs loaded heparin nanoparticles could also be administered through orally for noninvasive imaging. Due to promising features of heparin such as less toxic polysaccharide and easier modification, it was considered as a potent carrier for imaging agent and drug delivery.
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http://dx.doi.org/10.3978/j.issn.2223-4292.2012.09.01DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3496510PMC
September 2012
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