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Jung Hwan Hwang,
Young-Woock Noh,
Jung-Hyun Choi,
Jung-Ran Noh,
Yong-Hoon Kim,
Gil-Tae Gang,
Kyoung-Shim Kim,
Hye Sun Park,
Yong Taik Lim,
Hyeyoung Moon,
Kwan Soo Hong,
Hee Gu Lee, Bong Hyun Chung,
Chul-Ho Lee
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ABSTRACT: PURPOSE: We determined whether poly(lactic-co-glycolic acid) nanoparticles would be a useful reagent for the successful monitoring of isolated islets by magnetic resonance imaging and optical imaging systems, without clinically relevant toxicity in vitro or in vivo. METHODS: We used iron oxide for MR imaging and a cyanide dye approved by the Food and Drug Administration (indocyanine green) for optical imaging and estimated the in vivo detection of transplanted pancreatic islets. RESULTS: The poly(lactic-co-glycolic acid) nanoparticles were associated with the islets in vitro and were successfully detected by 4.7 T (MR) and optical imaging, without other toxic effects. When labeled islets were transplanted under the mouse kidney capsule, in vivo T2 / T2*-weighted scans with 4.7 T MR detected as few as 300 labeled islets by 4 weeks. Optical in vivo imaging revealed indocyanine green fluorescence by 2 and 4 days after transplantation of islets containing 250 and 500 µg/mL poly(lactic-co-glycolic acid) nanoparticles, respectively. These results were further supported by the immunohistochemical results for insulin and iron in the recipient mouse kidney and pancreas. CONCLUSIONS: Taken together, these data indicate that poly(lactic-co-glycolic acid) nanoparticles may be used to label transplanted islets and may be imaged with in vivo MR and optical imaging systems. Magn Reson Med, 2013. © 2013 Wiley Periodicals, Inc.
Magnetic Resonance in Medicine 05/2013; · 2.96 Impact Factor
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ABSTRACT: We developed a new detection method for l-Dopa decarboxylase (DDC) activity using gold nanoparticles (AuNPs). When l-3,4-dihydroxyphenylalanine (l-Dopa) is decarboxylated to dopamine (DA) by DDC, DA induces the aggregation of AuNPs, and the color of the AuNPs changes from red to blue.
The Analyst 04/2013; · 4.23 Impact Factor
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ABSTRACT: PURPOSE: The aim of this study was to perform the detection of folate receptor (FR)-positive tumors with a bimodal imaging contrast agent, a perfluorocarbon (PFC)/rhodamine nanoemulsion, providing both (19)F-based magnetic resonance imaging (MRI) and fluorescence imaging capabilities. PROCEDURES: The PFC/rhodamine nanoemulsion was further infused with phospholipid-anchored folate to improve the ability to target FR-expressing tumors. The preferential accumulation of the FR-targeted bimodal nanoemulsion in FR-positive tumor sites was monitored by both (19)F-MRI and optical imaging. RESULTS: The FR-targeted PFC nanoemulsion had no significant effect on cell viability, and the size and fluorescence signal of PFC nanoemulsion were very stable. These nanoprobes were successfully delivered into FR-positive tumor xenograft models and showed significantly enhanced signal intensities of (19)F-MRI and fluorescence imaging in the tumor area. CONCLUSIONS: The folate-PFC/rhodamine nanoemulsion has a great potential to serve as a useful optical and (19)F-MRI agent for the diagnosis and targeting of FR-positive tumor.
Molecular imaging and biology: MIB: the official publication of the Academy of Molecular Imaging 03/2013; · 2.47 Impact Factor
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ABSTRACT: Integration of biocompatible silica with a fluorescent polymer (PDDF) and superparamagnetic iron oxide nanoparticles (Fe(3) O(4) ) to form uniform core-shell nanostructures has the great potential to form particles for use in multimodal bioimaging applications. Core-shell nanoparticles (PDDF/Fe(3) O(4) @SiO(2) ) exhibit fluorescent and magnetic properties that are favorable for their use in magnetic separation and guiding applications, as well as optical and magnetic resonance (MR) imaging capabilities. With the biological analysis in an in vitro intracellular permeation and cytotoxicity test, chemical conjugation of the surface using folic acid (FA) molecules can provide the nanoparticles with cell-targeting properties, localizing the nanoparticles to folate receptors (FRs) on target KB cells that over-express the FRs.
Macromolecular Bioscience 12/2012; · 3.89 Impact Factor
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ABSTRACT: We developed a colorimetric method to specifically detect single-strand DNA breaks using gold nanoparticles. In our assay, broken DNA cannot stabilize gold nanoparticles to prevent salt-induced aggregation as good as intact DNA can, and this effect can be easily observed with the naked eye as a red-to-purple color change.
The Analyst 12/2012; · 4.23 Impact Factor
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ABSTRACT: There has been great progress in the development of functional DNA-based sensors for the detection of metal ions. However, many functional DNAs are vulnerable to hydrolysis by nucleases in human blood. In addition, the detection methods that are based on DNA often exhibit interference due to the high blood concentrations of other ions, such as K(+) and Na(+). Therefore, we selected highly Pb(2+)-specific DNA-aptamer sequences based on CD spectroscopy of 4 G-rich DNA sequences and Hg(2+)-specific T-rich DNA sequences and immobilized them on gold nanoparticles for the simultaneous detection of Pb(2+) and Hg(2+) in human serum. We used gold nanoparticles because these have a superior fluorescence-quenching efficiency over a broad range of wavelengths compared with other organic quenchers. In addition, gold nanoparticles have a stabilizing effect on the immobilized DNA, which makes it more resistant to degradation by nucleases than free DNA. As a result, even in the presence of DNase, we were able to simultaneously detect Pb(2+) and Hg(2+) in serum at concentrations as low as 128pM and 121pM, respectively, within 10min. These detection limits for Pb(2+) and Hg(2+) were 39-fold and 26.4-fold lower, respectively, than the detection limits that were obtained using free DNAs. Given the multi-color-fluorescence quenching capability of the gold nanoparticles and the possibility of developing functional nucleic acids for the detection of other metal ions, this study extends the application of oligonucleotides to a point-of-care detection system for the detection of multiple harmful metal ions in body fluids.
Biosensors & bioelectronics 10/2012; · 5.43 Impact Factor
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ABSTRACT: The real-time monitoring of the caspase cascade in cancer cells during apoptosis was performed using various caspase substrate-linked fluorescent proteins-conjugated gold nanoparticles as a new imaging probe.
Chemical Communications 09/2012; 48(85):10547-9. · 6.17 Impact Factor
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ABSTRACT: Indocyanine green (ICG) encapsulated hyaluronic acid (HA) nanogels were first studied for highly selective detection of specific cancers and lymph nodes via hyaluronidase sensitive switch-on of near infrared fluorescence as a long-lasting and stimuli-responsive imaging probe.
Chemical Communications 06/2012; 48(69):8628-30. · 6.17 Impact Factor
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ABSTRACT: We introduce a scanometric detection method for the analysis of DNA microarrays using DNA intercalator-conjugated gold nanoparticles that can be analyzed with the naked eye or with an optical scanner after the enhancement of the AuNPs. Moreover, we successfully detected a hemagglutinin-subtyping DNA array using this method.
Chemical Communications 06/2012; 48(61):7601-3. · 6.17 Impact Factor
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ABSTRACT: A charge-converting and pH-dependent nanocarrier was achieved by conjugating 2,3-dimethylmaleic anhydride (DMMA) to the amino group of an octadecyl grafted poly (2-hydroxyethyl aspartamide) (PHEA-g-C(18)-NH(2)) backbone, thereby forming a spherical micelle. PHEA, a poly(amino acid)s derivative, was derived from poly(succinimide), which is biocompatible and biodegradable. DMMA, a detachable component at the tumor site, was added, preventing aggregation with negative blood serum and enhancing the nanocarrier's cellular uptake. The polymeric micelle was comprehensively characterized and doxorubicin was encapsulated successively. The cellular uptake and anticancer therapeutic effect were evaluated by flow cytometry, confocal laser scanning microscopy, and a MTT assay. The properties of the nanocarrier can further be exploited to develop an early detection module for cancer. The present work is also expected to advance the study of designing smart carriers for drug and gene delivery.
Journal of Biomedical Materials Research Part A 05/2012; 100(8):2027-33. · 2.63 Impact Factor
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ABSTRACT: Recently, new virulent strain of Escherichia coli (E. coli) bacteria (0104:H4) was identified, causing ongoing outbreak of food poisoning in Europe, infecting up to 1,600 people with
18 deaths, especially in Germany. More common strain of E. coli for the hemorrhagic colitis and hemolytic uremic syndrome in human from food poisoning was E. coli O157:H7 (O157). Hence, various diagnostic methods for detecting O157 using staining procedure, PCR after cell lysis, sandwich
ELISA, electrochemical biosonsors, and SPR biosensor were developed to expedite the detection time. In this study, our aim
was to detect and monitor O157 non-invasively without lysing cells by using its endogenous membrane peroxidase. The genomic
analysis revealed that O157 had seven different peroxidases, however, their expression levels, locations, or activities had
not been revealed. Various peroxidase substrates for the detection by absorption, fluorescence and luminescence spectroscopies
revealed 3,3′,5,5′ Tetramethylbenzidine (TMB), as the best peroxidase substrate against O157. Using TMB, the membrane peroxidase
of O157 could be detected in 30 to 60 min with the detection levels of 105 cells/mL, comparable to current ELISA kits. Since TMB is a well-known colorimetric HRP substrate without using sophisticated
equipments and procedures, the quantification of O157 with the hand-held portable device could yield compatible detection
limit. In future, in conjunction with conjugated anti-O157 antibody on magnetic beads, the present method of using endogenous
membrane peroxidases could be further developed to a simple point of care test system to be used in the field.
Keywords
Escherichia coli
–O157:H7–Endogeneous membrane peroxidase–Listeira–Staphylococcus aureus
04/2012; 3(2):80-85.
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ABSTRACT: A recombinant human growth hormone (hGH) was expressed as a secretory product in the yeastSaccharomyces cerevisiae. Three different leader sequences derived from the mating factor α1 (MFα1), inulinase and invertase were used to direct the
secretion of hGH into the extracellular medium. Among three leader sequences tested, the inulinase leader sequence was found
to be the most efficient in the secretory expression of hGH. In contrast, no hGH was detected in the extracellular medium
with the invertase leader sequence. After 48 h shake-flask culture, the yields of hGH secreted into the medium by the invertase,
MFα1, inulinase and invertase leader sequences were approximately 0, 0.3 and 0.9 mg/L, respectively. The secretion efficiencies
were also found to be 0, 3.8 and 13% for the invertase, MFα1 and inulinase leader sequences, respectively.
Biotechnology and Bioprocess Engineering 04/2012; 6(4):306-309. · 1.28 Impact Factor
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ABSTRACT: The selective removal of impurity proteins and colloidal particles from milk prior to chromatographic purification processes
presents a crucial issue in the production of therapeutic proteins from transgenic animals with high recovery yield and purity.
We have developed an efficient two-step precipitation method for the recovery of the recombinant human erythropoietin (rhEPO)
of interest from transgenic sow milk. Here, rhEPO was partially purified from transgenic sow milk via a two-step precipitation
method consisting of ammonium sulfate and divalent metal precipitations, with a yield of approximately 82.1% and a purification
fold of 10.4 at a copper concentration of 30 mM. Copper proved to be the strongest flocculating agent among the divalent ions
tested for the aggregation of milk proteins under 35%, with ammonium sulfate, zinc, nickel, and calcium demonstrating increasing
flocculating capability in the given order. Copper and zinc proved to be appropriate divalent metals for the recovery of rhEPO
at high yield and purity, and the optimal concentration ranges of copper and zinc were 20~40 and 40~80 mM, respectively.
Biotechnology and Bioprocess Engineering 04/2012; 13(2):189-196. · 1.28 Impact Factor
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Hyou-Arm Joung,
Won-Bo Shim,
Duck-Hwa Chung,
Junhyoung Ahn, Bong Hyun Chung,
Ho-Suk Choi,
Sang-Do Ha,
Keun-Sung Kim,
Kyu-Ho Lee,
Cheol-Ho Kim,
Kwang-Yup Kim,
Min-Gon Kim
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ABSTRACT: In this study, a specific monoclonal antibody againstListeria monocytogenes was screened using an SPR biosensor Monoclonal antibodies were bound to protein L, after which theL. monocytogenes cells were subjected to an affinity assay. Protein L was immobilized on a carboxymethyl dextran (CM-Dex) surface via an amine
coupling method and utilized repeatedly by regeneration. The monoclonal antibody, ‘A18’, was selected and employed for the
high-sensitivity detection ofL. monocytogenes. Under optimized conditions, 103 cells/ml or 50 cells were detected by the SPR biosensor.
Biotechnology and Bioprocess Engineering 04/2012; 12(2):80-85. · 1.28 Impact Factor
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ABSTRACT: In this study, a simple procedure is described for patterning biotin on a glass substrate and then selectively immobilizing
proteins of interest onto the biotin-patterned surface. Microcontact printing (μCP) was used to generate the micropattern
of biotin and to demonstrate the selective immobilization of proteins by using enhanced green fluorescent protein (EGFP) as
a model protein, of which the C-terminus was fused to a core streptavidin (cSA) gene ofStreptomyces avidinii. Confocal fluorescence microscopy was used to visualize the pattern of the immobilized protein (EGFP-cSA), and surface plasmon
resonance was used to characterize biological activity of the immobilized EGFP-cSA. The results suggest that this strategy,
which consists of a combination of μμCP and cSA-fused proteins, is an effective way for fabricating biologically active substrates
that are suitable for a wide variety of applications, one such being the use in protein-protein assays.
Biotechnology and Bioprocess Engineering 04/2012; 9(2):137-142. · 1.28 Impact Factor
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ABSTRACT: A surface plasmon resonance (SPR) imaging system was constructed and used to detect the hexahistidine-ubiquitin-tagged human
parathyroid hormone fragment (His6-Ub-hPTHF(1–34)) expressed inEscherichia coli. The hexahistidine-specific antibody was immobilized on a thin gold film coated with ProLinkerTM B, a novel calixcrown derivative with a bifunctional coupling property that permits efficient immobilization of capture proteins
on solid matrices. The soluble and insoluble fractions of anE. coli cell lysate were spotted onto the antibody-coated gold chip, which was then washed with buffer (pH 7.4) solution and dried.
SPR imaging measurements were carried out to detect the expressed His6-Ub-hPTHF (1–34). There was no discernible protein image in the uninduced cell lysate, indicating that non-specific binding
of contaminant proteins did not occur on the gold chip surface. It is expected that the approach used here to detect affinity-tagged
recombinant proteins using an SPR imaging technique could be used as a powerful tool for the analyses of a number of proteins
in a high-throughput mode.
Biotechnology and Bioprocess Engineering 04/2012; 9(2):143-146. · 1.28 Impact Factor
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ABSTRACT: Human lipocortin-I was expressed as a secretory product bySaccharomyces cerevisiae harboring an expression system consisting ofGAL10 promoter, inulinase signal sequence and lipocortin-I terminator. Fed-batch fermentation was carried out to overproduce recombinant
human lipocortin-I. The culture medium was desalted and concentrated by ultrafiltration, and then subjected to hydroxyapatite
column chromatography. The lipocortin-I was purified to >98% purity by single-step hydroxyapatite column chromatography. However,
it was found that the purified lipocortin-I was a proteolytically-cleaved form which was cleaved immediately after the basic
amino acid Lys26.
Biotechnology and Bioprocess Engineering 04/2012; 5(4):242-246. · 1.28 Impact Factor
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ABSTRACT: Although the safety of gold nanoparticle (AuNP) use is of growing concern, most toxicity studies of AuNPs had focused on their chemical characteristics, including their physical dimensions, surface chemistry, and shape. The present study examined the susceptibility of rodents with healthy or damaged livers to AuNP-induced hepatotoxicity. To induce a model of liver injury, mice were fed a methionine- and choline-deficient (MCD) diet for 4 weeks. Sizes and biodistribution of 15-nm PEGylated AuNPs were analyzed by transmission electron microscopy. Levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were estimated with an automatic chemical analyzer, and liver sections were subjected to pathological examination. Activities of antioxidant enzymes were determined by biochemical assay. Lateral tail vein injection of MCD diet-fed mice with 5 mg kg(-1) AuNPs significantly elevated the serum ALT and AST levels compared to MCD diet-fed mice injected with mPEG (methylpolyethylene glycol). Similarly, severe hepatic cell damage, acute inflammation, and increased apoptosis and reactive oxygen species (ROS) production were observed in the livers of AuNP-injected mice on the MCD diet; these liver injuries were attenuated in mice fed a normal chow diet. The results suggest that AuNPs display toxicity in a stressed liver environment by stimulating the inflammatory response and accelerating stress-induced apoptosis. These conclusions may point to the importance of considering health conditions, including liver damage, in medical applications of AuNPs.
Toxicology 03/2012; 294(1):27-35. · 3.68 Impact Factor
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ABSTRACT: Highly water-soluble and color-tunable photoluminescent fullerene nanoparticles are synthesized by using tetraethylene glycol (TEG) and lithium hydroxide as a catalyst. The maximum PL emission changes depend on the contents of the remaining π-conjugation in oxidized C(60), which is partially covalently conjugated with TEG. The PL behavior is attributed to an electronic transition change due to the distortion of symmetrical C(60).
Advanced Materials 03/2012; 24(15):1999-2003. · 13.88 Impact Factor
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ABSTRACT: Cross-linked magnetic nanoparticles were developed to improve the structural stability of amphiphilic polymer coated magnetic nanoparticles. These nanoparticles show strong potential for biomedical applications such as magnetic resonance imaging (MRI).
Chemical Communications 12/2011; 47(46):12518-20. · 6.17 Impact Factor
