• Journal of Sensor Science and Technology
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• v.16 no.6
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• pp.441-448
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• 2007

In this study, the fiber-optic fluoro-immunosensor was designed to detect foodborne pathogens. The fabricated system is composed of the multimode optical fiber on which antibodies are immobilized. Then, a sandwich immunoassay is applied to the fabricated the fiber-optic fluoro-immunosensor. In the "sandwich" binding format, a primary or "capture" antibody is immobilized on the core surface of the multimode optical fiber and a secondary or named as "tracer" antibody is added to the bulk solution. A tracer is labeled FITC (fluorescein isothiocyanate; ${\lambda}ex$=492 nm, ${\lambda}em$= 520 nm). Different concentrations of antigens are tested in different fibers. The detection limit of the fabricated system is 5.08×103 cfu/ml for Vibrio antigen and $0.1{\mu}g/ml$, $0.05{\mu}g/ml$ in non-labeled monolayer phosphate buffered saline (NMP), non-labeled monolayer carbonate bicarbonate buffer (NMC), respectively.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.703-706
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• 2000

We constructed a biospecific affinity surface using hyper-branched dendrimers on gold for biospecific recognition, and characterized the resulting surfaces by using confocal fluorescence microscopy. The dendrimer monolayer was firstly constructed on the mercaptoundecanoic acid SAM/Au with pentafluorophenyl ester activation and further functionalized with sulfo-NHS-biotin, an activated ester of biotin. To confirm the formation of biospecific affinity surface, FITC(fluorescein isothiocyanate)-labeled avidin was loaded onto the biotinylated dendrimer monolayer, and fluorescence images of the bound avidins were investigated with a confocal microscope. The constructed biospecific affinity surface showed a much more dense and uniform fluorescence compared to those from poly-L-lysine- and cystamine SAM-based affinity surfaces. For the dependency on the concentration of added FITC-labeled avidin on the affinity surface, derived fluorescence could be detectable from as low as $1{\mu}g/ml$, and intensified up to $50{\mu}g/ml$. Further reaction of FITC-labeled avidin layer with TMR(tetramethylrhodamine)-biocytins resulted in the efficient FRET(fluorescence resonance energy transfer) phenomenon. As an extension of the study, we attempted a patterning of the affinity surfaces on gold by microcontact printing. Fluorescence of the patterned surface demonstrated that FITC-labeled avidin molecules were specifically bound to the biotinylated patches.

• Biomolecules & Therapeutics
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• v.26 no.2
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• pp.182-190
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• 2018

The objective of this work is to evaluate the effect of polyamidoamine (PAMAM) dendrimers on electroosmotic flow (EOF) through skin. The effect of size and concentration of dendrimer was studied, using generation 1, 4 and 7 dendrimer (G1, G4 and G7, respectively). As a marker molecule for the direction and magnitude of EOF, a neutral molecule, acetoaminophen (AAP) was used. The visualization of dendrimer permeation into the current conducting pore (CCP) of skin was made using G4-fluorescein isothiocyanate (FITC) conjugate and confocal microscopy. Without dendrimer, anodal flux of AAP was much higher than cathodal or passive flux. When G1 dendrimer was added, anodal flux decreased, presumably due to the decrease in EOF by the association of G1 dendrimer with net negative charge in CCP. As the generation increased, larger decrease in anodal flux was observed, and the direction of EOF was reversed. Small amount of methanol used for the preparation of dendrimer solution also contributed to the decrease in anodal flux of AAP. Cross-sectional view perpendicular to the skin surface by confocal laser scanning microscope (CLSM) study showed that G4 dendrimer-FITC conjugate (G4-FITC) can penetrate into the viable epidermis and dermis under anodal current. The permeation route seemed to be localized on hair follicle region. These results suggest that PAMAM dendrimers can permeate into CCP and change the magnitude and direction of EOF. Overall, we obtained a better understanding on the mechanistic insights into the electroosmosis phenomena and its role on flux during iontophoresis.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.632-637
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• 2009

Poly(${\varepsilon}-caprolacton$)/ethyl cellulose (PCL/EC) microcapsules containing pluronic F127 were prepared by a spray drying method. The aqueous phase, 20% of pluronic F127 was dissolved in distilled water, and the organic phase, 5% of PCL and EC were dissolved in dichloromethane. The microcapsules were obtained by spray drying the water-in-oil (W/O) emulsion. According to the data of scanning electron microscopy and particle analyzer, tens of micro size microcapsules were observed. On a differential scanning calorimeter, the phase transition temperatures of microcapsules were observed and they were found around those of pluronic F127 and poly(${\varepsilon}-caprolacton$), which were the main components of the microcapsules. At the range of $30{\sim}45^{\circ}C$, temperature-dependent release properties were investigated using fluorescein isothicyanate-dextran (FITC-dextran) and blue dextran as a model drug. When the temperature was increased, the degree of release of microcapsule was also increased. FITC-dextran, the relative low molecular weight, was more released than blue-dextran.

• Animal cells and systems
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• v.5 no.1
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• pp.51-57
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• 2001

We have previously shown that oocyte maturation is induced by an immobilized progesterone, progesterone-3-carboxymethyloxime - bovine serum albumin conjugate (P-BSA) in Rana dybowskii. In this study, we confirmed the maturation inducing activity of P-BSA on Xenopus oocyte and examined the binding character of the immobilized progesterone on the surface of Xenopus oocytes after removal of the vitelline layer. P-BSA induced maturation of Xenopus oocytes but E-BSA failed to do so as observed in Rana. Binding of the immobilized progesterone, fluorescein isothiocyanate-labeled progesterone-3-0-carboxymethyloxime-BSA (P-BSA-FITC) on the devitellined oocytes surface was examined by fluorescence confocal microscopy. The binding affinity of P-BSA-FITC to the devitellined oocyte was higher than that of estrogen-BSA-FITC (E-BSA-FITC) or testosterone-BSA-FITC (T-BSA-FITC). The binding disappeared in the presence of excess free progesterone but not in the presence of free estrogen. Maximum binding occurred after two-hours of incubation with P-BSA-FITC at pH 7.5. Stronger binding occurred in oocytes at stage Vl than stage IV, and in vitro treatment of hCG enhanced the binding. Taken together, these results suggest that a specific receptor for progesterone exists on the plasma membrane of Xenopus oocytes and that progesterone acts initially on this putative receptors and triggers generation of membrane-mediated second messengers during the early stage of oocyte maturation In amphibians.

• Clinical and Experimental Reproductive Medicine
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• v.29 no.3
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• pp.179-186
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• 2002

Objective: Lectins are cell-agglutinating and sugar specific proteins or glycoproteins of non-immune origin that precipitate glycoconjugates having saccharides of appropriate complementarity. Because of these properties, plant lectins have been used to help characterize the carbohydrate moieties of glycoproteins in the zona pellucida (ZP) of several mammalian species including pigs. Treatment of oocytes with various lectins blocks sperm binding to the ZP in various mammalian species. This study was undertaken to examine the distribution of sugar residues in the ZP of pig oocytes matured in vitro and the ability of spermatozoa to bind to ZP and in vitro penetration in oocytes treated with fluorescein isothiocyanate (FITC)-labelled lectins. Materials and Methods: The lectins of Banderiaea simplicifolia (BS-II, bind to $\beta$-D-N-acetylglucosamine), Canavalin ensiformis (Con A, bind to $\alpha$-D-Mannose), Lens culinaris (LCA, bind to a-D-Mannose), Ricinus communis (RCA-I, bind to $\beta$-D-Galactose) and Ulex europaeus (UEA-I, bind to $\alpha$-L-Fucose) were examined for spermatozoa penetration, binding capacity to ZP and distribution of lectins. Results: The penetration rates were significantry (p<0.05) higher in control oocytes (63%) than those treated with all lectins, but penetration rates ($40{\sim}49%$) were simililar in group treated with lectins. The incidence of monospermy was similar in oocytes untreated and UEA-I, but it was higher in oocytes treated with BS-II, Con A, RCA-I and LCA. The porcine oocytes cultured for 48 h in TC-199 medium were freed from cumulus cells and treated for 30 min with fluorescein isothiocyanate-labelled lectins. When examined under fluorescein illumination, higher (p<0.001) proportions of oocytes showed fluorescein of zona pellucida after treatment with Con A (93%), LCA (93%) and RCA-I (100%) than BS-II (37%) and UEA-I (50%). All of the oocytes treated with RCA-I exhibited strong fluorescein in the outer region of the zona pellucida while those treated with LCA exhibited strong fluorescein throughout the zona pellucida. BS-II bounded mainly to the outer region and UEA-I bounded mainly to the inner region of the zona pellucida, with either strong or weak fluorescein. At 120 min after insemination in vitro, fewer spermatozoa were bound to the zona pellucida of the oocytes treated with BS-II, Con-A and RCA-I. Of the lectins, Con A most inhibited sperm binding. Conclusions: These results suggest that $\beta$-D-Galactose residues in the porcine zona pellucida may act as primary sperm receptors and inducers of the sperm acrosome reaction and these sugar residues may be involved in the block to polyspermy.

• Polymer(Korea)
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• v.29 no.3
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• pp.282-287
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• 2005

A novel ice particle leaching method for fabrication of porous and biodegradable PLGA scaffold has been proposed for the application to tissue engineering. After uniform mixing of poly(L-lactide-co-glycolide) (PLGA) and bovine serum albumin-fluorescein isothiocyanate (FITC-BSA), the FITC-BSA loaded scaffold was fabricated by adding various ratio of ice particle. The release profiles of FITC-BSA were examined using pH 7.4 PBS for 28 days at $37^{circ}$. The release amount was determined by fluorescence intensity by using the fluorescence spectrophotometer and the morphological change of the scaffolds was observed by scanning electron microscope. The release initial burst of BSA containing scaffolds was lower than that of simple dipping scaffolds resulting in constant release aspect. Although the BSA concentration increased. the initial burst was not increased. As a result of this study, it can be suggested that ice particle leaching method for the tissue engineered scaffold miff be very useful and it is possible to impregnate with water soluble factors like cytokine. We suggest that ice particle leaching method may be useful to tissue engineered organ regeneration.

• Journal of Biomedical Engineering Research
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• v.41 no.1
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• pp.62-66
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• 2020

Controlled drug release is important for effective treatment of cancer. Poly(DL-lactide-co-glycolide) acid (PLGA) is a Food and Drug Administration (FDA) approved polymer and have been extensively studied as drug delivery carriers with biodegradable and biocompatible properties. However, PLGA drug delivery carriers are limited due to the initial burst release of drug. Certain drugs require an early rapid release, but in many cases the initial rapid release can be inefficient, reducing therapeutic effects and also increasing side effects. Therefore, sustained release is important for effective treatment. Poly Lactic Acid stereo complex (PLA SC) is resistant to hydrolysis and has high stability in aqueous solutions. Therefore, in this work, PLGA based discoidal polymeric particles are modified by Poly Lactic Acid stereocomplex (PLAsc DPPs). PLAsc DPPs are 3 ㎛ in diameter, also showing a relatively sustained release profile. Fluorescein 5(6)-isothiocyanate (FITC) released from PLAsc DPPs was continuously observed until 38 days, which showed the initial release of FITC from PLAsc DPPs was about 3.9-fold reduced as compared to PLGA based DPPs at 1 hour.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.3
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• pp.620-624
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• 2009

Apolipophorin-III (apoLp-III) was isolated and purified from the last instar larval hemolymph of Galleria mellonella by gel chromatography (Sephadex G-100) and ion exchange chromatography (CM-52). In the present study, I wanted to show that apoLp-III is taken up into the adult ovary in Galleria mellonella. Adult ovary tissues were incubated at room temperature for 30 min with fluorescein isothiocyanate (FITC)-labeled apoLp-III. Fluorescence microscopy and sodium dodecylsulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) revealed that adult ovary tissues internalize fluorescence-labeled apoLp-III. The results suggest that apoLp-III is taken up by the adult ovary.

• BioChip Journal
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• v.12 no.4
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• pp.317-325
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• 2018

This paper investigated the effects of ionic strength in the medium on a preconcentrator for a protein sample with low concentration. The preconcentration chip was designed and fabricated using a polydimethylsiloxane replica through standard lithophotography. A glass substrate is silanized prior to functionalizing the nanoparticles for self-assembly at a designed region. Due to the overlap of electrical double layers in a nanofluidic channel, a concentration polarization effect can be achieved using an electric field. A nonlinear electrokinetic flow is induced, resulting in the fast accumulation of proteins in front of the induced ionic depletion zone, so called exclusion-enrichment effect. Thus, the protein sample can be driven by electroosmotic flow and accumulated at a specific location. The chip is used to collect fluorescein isothiocyanate-labeled bovine serum albumin (FITC-BSA) diluted in phosphate-buffered saline (PBS) buffer solution. Different concentrations of the buffer media were studied herein. Fluorescence intensity images show that the buffer concentration of 4 mM is more appropriate than all the other ones. The sample of FITC-BSA with an initial concentration of $10{\mu}M$ in the 4 mM PBS solution increases its concentration at the desired region by up to 50 times within 30 min, demonstrating the results in this investigation.