Biomedical subjects

Chong-Su Cho

Publications and source records attributed to Chong-Su Cho.

At least 19 recordsLinked to original sources

PubMed2006

Asialoglycoprotein-receptor-targeted hepatocyte imaging using 99mTc galactosylated chitosan.

This study investigated the usefulness of 99mTc hydrazinonicotinamide-galactosylated chitosan (HGC) in hepatocyte imaging. HGC was obtained by coupling the galactose moiety of both lactobionic acid and succinimidyl 6-hydrazinonicotinate hydrochloride (succinimidyl HYNIC). The coupled product was then radiolabeled with 99mTc using stannous chloride and tricine as reducing agent and coligand, respectively. Labeling efficiency was >90% both in room temperature and in serum up to 24 h after injection. The hepatic uptake properties of 99mTc HGC were studied in Balb/C mice. 99mTc HGC and 99mTc hydrazinonicotinamide chitosan (HC) were intravenously injected into mice, with receptor binding identified by coinjection with 9 and 14 mg of free galactose. Images were acquired with a gamma-camera. After injection via the tail vein of the mice, 99mTc HGC showed high selectivity for the liver, while 99mTc HC without a galactose group showed low liver uptake. In addition, the hepatic uptake of 99mTc HGC was blocked by coinjection of free galactose. Tissue distribution was determined at three different times (10, 60 and 120 min). The liver accumulated 13.16+/-2.72%, 16.11+/-5.70% and 16.55+/-2.28% of the injected dose per gram at 10, 60 and 120 min after injection, respectively. 99mTc HGC showed specific and rapid targeting of hepatocytes. It is a promising receptor-specific radiopharmaceutical with potential applications in liver imaging for the evaluation of hepatocytic function.

Animals↗

PubMed2006

Effect of photo-immobilization of epidermal growth factor on the cellular behaviors.

We constructed photo-reactive epidermal growth factor (EGF) bearing p-azido phenylalanine at the C-terminal (HEGFP) by genetic engineering to investigate the possibility of immobilized EGF as a novel artificial extracellular matrix (ECM). The constructed recombinant protein was immobilized to glass surface by ultraviolet irradiation. A431 cells adhered both to HEGFP-immobilized and collagen-coated surfaces. Interaction between immobilized HEGFP and EGF receptors in the A431 cells was independent of Mg(2+) although integrin-mediated cell adhesion to natural ECMs is dependent on Mg(2+). Phosphorylation of EGF receptors in A431 cells was induced by immobilized HEGFP as same as soluble EGF. DNA uptake of hepatocytes decreased by immobilized HEGFP whereas it increased by soluble EGF. Liver-specific functions of hepatocytes were maintained for 3 days by immobilized HEGFP whereas they were not maintained by soluble EGF, indicating that immobilized HEGFP follows different signal transduction pathway from soluble EGF.

Adsorption↗

PubMed2006

Regulation of transduction efficiency by pegylation of baculovirus vector in vitro and in vivo.

In this study, poly(ethylene glycol) (PEG) was coupled to baculovirus to regulate transduction efficiency of baculovirus in vitro and in vivo. The degree of pegylation in virions was measured by the loss of free amines via a fluorescamine-based assay. The efficiency of green fluorescent protein (GFP) expression was used to monitor transduction efficiency. As the results, the transduction efficiency in pegylated baculovirus was decreased with an increase of pegylation in baculovirus in vitro and in vivo. Interestingly, the transduction efficiency of the pegylated baculovirus for the lung and brain was increased compared with baculovirus itself possibly owing to increased stability of baculovirus by pegylation.

Animals↗

PubMed2006

In vivo induction of mucosal immune responses by intranasal administration of chitosan microspheres containing Bordetella bronchiseptica DNT.

In vitro immune-stimulating activities of Bordetella bronchiseptica dermonecrotoxin (BBD)-loaded in chitosan microspheres (CMs) were reported with a mouse alveolar macrophage cell line (RAW264.7). Based on the report, in vivo activity of immune-induction was investigated by intranasal administration of the BBD-loaded CMs into mice. BBD was loaded into the CMs prepared by an ionic gelation process with tripolyphosphate. Mice were immunized by direct administration of the BBD-loaded CMs into the nasal cavity. After immunization of the mice, BBD-specific immune responses (IgG and IgA titers) were measured in sera, nasal wash, and saliva by ELISA. BBD-specific IgA titers in the nasal cavity were time- and dose-dependently increased by the administration. Similar phenomena were observed in the analysis of systemic IgA and IgG in sera. However, the antibody in saliva was undetectable by ELISA. These results suggested that direct vaccination via the nasal cavity was effective for targeting nasal-associated lymphoid tissues, and that CMs were an efficient adjuvant in nasal mucosal immunity for atrophic rhinitis vaccine.

Administration, Intranasal↗

PubMed2006

Preparation of semi-interpenetrating polymer networks composed of chitosan and poloxamer.

Through semi-interpenetration of polymer networks with poloxamer, mechanical properties of chitosan (CS) sponge were increased for wound dressing application. Synthesis of poloxamer macromer was confirmed by proton nuclear magnetic resonance (1H NMR) spectra. Possible interactions between CS and poloxamer in semi-interpenetrating polymer networks (SIPNs), and changes in crystalline structures of both polymers were evaluated by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), respectively. Swelling behavior, thermal analysis, mechanical properties, and morphology of SIPNs were studied by thermal gravimetric analysis, differential scanning calorimetry (DSC), compressive modulus measurement, and scanning electron microscopy (SEM), respectively. Preparation of poloxamer macromer, and intermolecular hydrogen bonding between CS and poloxamer were confirmed by NMR and FTIR, respectively. Melting temperature of poloxamer in SIPNs decreased due to prevention of crystallization by incorporation of CS. Formation of SIPNs with poloxamer and increasing poloxamer content in CS/poloxamer SIPNs increased mechanical strength of CS sponge compared with CS/poloxamer blend. Formation of SIPNs with poloxamer remarkably increased water content of CS due to hydrophilicity of CS and poloxamer. These results suggest CS/poloxamer sponges prepared by SIPNs method have good possibility for wound dressing application owing to rapid water adsorption, high mechanical strength, and interconnected cross-sectional morphology of SIPNs.

Adsorption↗

PubMed2006

Alginate/galactosylated chitosan/heparin scaffold as a new synthetic extracellular matrix for hepatocytes.

Formation of multicellular hepatocyte spheroids in the three-dimensional culture is a potential approach for enhancing liver-specific functions in bioartificial liver (BAL) devices. In this study, as a synthetic extracellular matrix (ECM) for hepatocytes, a highly porous hydrogel (sponge-like) scaffold, 150-200 microm pore size in diameter, was fabricated with alginate (AL), galactosylated chitosan (GC), and heparin through electrostatic interaction. We attempt to select the best condition of AL/GC/heparin sponges for coculture with NIH3T3, as well as compare the liver-specific functions with monoculture. Cell adhesion to GC based on AL film was significantly increased with increasing GC concentration, but not to chitosan regardless of its concentration. The optimal concentration of GC and heparin in AL/GC/heparin sponges to perform the best liver-specific function was 1 and 6 wt% to AL contents, respectively, where albumin secretion were maintained with maximal rates. The mechanical properties in tensile strength of three types of sponges were very slightly different from one another. Cell viabilities performed on AL, AL/GC, and AL/GC/heparin sponges were 68.5, 83.3, and 90.4 % of control, respectively, after 15 days of incubation. Hepatocyte spheroids were more rapidly formed in the AL/GC and AL/GC/heparin sponges, with diameter enlarged to about 100 microm, than in AL sponges. Connexin32 and E-cadherin genes correlated with cell-to-cell adhesion were expressed in hepatocytes within AL/GC and AL/GC/heparin sponges at 36 h after incubation, but not in AL sponges. Treatment of a gap junctional intercellular communication (GJIC) inhibitor, 18beta-glycyrrhetinic acid, indicates that cell aggregation without GJIC does not perform the liver-specific functions for long periods. In the presence of HGF, the level of albumin secretion in AL/GC/heparin sponges was markedly elevated compared to that in AL/GC sponges. Coculture of hepatocytes in AL/GC/heparin sponges with NIH3T3 in a transwell insert resulted in significant increase of liver-specific functions, such as improved albumin secretion rates, ammonia elimination rates, and ethoxyresorufin-O-deethylase activity by cytochrome P4501A1 compared to those in hepatocyte monoculture. The results suggest that hepatocytes as stable spheroids enhance liver-specific functions in AL/GC/heparin sponges, providing a new synthetic ECM to design BAL devices.

Alginates↗

PubMed2005

Asialoglycoprotein receptor targeted gene delivery using galactosylated polyethylenimine-graft-poly(ethylene glycol): in vitro and in vivo studies.

The asialoglycoprotein receptor (ASGP-R) on the hepatocyte membrane is a specific targeting marker for gene and drug delivery. Polyethylenimine (PEI) is a polycationic nonviral vector that is used for gene transfer. We have synthesized galactosylated polyethylenimine-graft-poly(ethylene glycol) (GPP) for performing gene delivery to the hepatocytes. The present study reports on the in vitro and in vivo data that was achieved in hepatoma bearing transgenic mice. The cytotoxicity was decreased with the increasing PEG content. The particle size of the complex was increased with the increasing PEG at an N/P ratio of 3.0, while the zeta potentials were decreased. The (99m)Tc labeled complexes were transfected into HepG2 and HeLa cells, while the GFP reporter genes were mainly expressed in the HepG2 cells. The in vivo data was achieved in ALB/c-Ha-ras transgenic mice. (99m)Tc labeled GPP(50)/DNA was injected into the mice via the tail vein, and the gamma images were acquired at 5, 15 and 30 min. The (99m)Tc labeled complexes were mainly localized in the heart and liver, and they were excreted through the kidneys. The GFP gene was mainly expressed in the proliferating cells at the tumor periphery. This result was confirmed by PCNA staining. The GPP(50)/DNA complexes were bound to ASGP-R of the proliferating hepatocytes in vitro and in vivo. The present results demonstrate the feasibility of nonviral gene transfer using galactosylated PEI-PEG in vivo.

Animals↗

PubMed2005

Enhanced liver functions of hepatocytes cocultured with NIH 3T3 in the alginate/galactosylated chitosan scaffold.

Formation of primary hepatocyte spheroids in the hydrogel scaffold is a promising approach for enhancing liver-specific functions in liver tissue engineering as well as for developing bioartificial liver (BAL) devices. In the present study, a highly porous hydrogel scaffold composed of alginate (AL) and galactosylated chitosan (GC) as a synthetic extracellular matrix (ECM) for hepatocytes was fabricated with 150-200 microm pore size in diameter. Cell adhesion onto AL/GC and AL/chitosan film was 72.7 and 45% at 1 wt% of GC (or chitosan) to AL content whereas cell adhesion onto AL film was 28.5%. The optimal concentration of GC in AL/GC sponge was 1 wt% to AL content by the measurement of albumin secretion. Cell viabilities performed on AL and AL/GC sponges were 72.2+/-3.6 and 81.3+/-3.5% of control, respectively, after 10 days incubation. Hepatocytes were aggregated to form multicellular spheroids in AL/GC sponge with diameter enlarged up to about 100 microm, 36 h postseeding, whereas most of them in the AL sponge remained as single cells and only a few cells began to form aggregates. Intercellular molecules such as connexin32 and E-cadherin genes related with cell-cell contact were expressed in hepatocytes within AL/GC sponge at 36 h after incubation, but not in AL sponge. Treatment with a gap junctional intercellular communication (GJIC) inhibitor, 18beta-glycyrrhetinic acid, resulted in a 1.5-fold marked decrease in albumin secretion levels in AL/GC sponge. Specially, coculture of hepatocytes in AL and AL/GC sponges with NIH3T3 in a transwell insert resulted in enhanced increase of liver-specific functions, such as albumin secretion rates, ammonia elimination rates, and ethoxyresorufin-O-deethylase activity by cytochrome P4501A1, compared to those in hepatocyte monoculture. The results suggest that formation of hepatocyte spheroids in coculture system enhances liver-specific functions for the AL/GC sponge as a new synthetic ECM to design developed BAL devices.

Alginates↗

PubMed2005

Cellular recognition of paclitaxel-loaded polymeric nanoparticles composed of poly(gamma-benzyl L-glutamate) and poly(ethylene glycol) diblock copolymer endcapped with galactose moiety.

Poly(gamma-benzyl L-glutamate) (PBLG)/poly(ethylene glycol) (PEG) diblock copolymer endcapped with galactose moiety (abbreviated as GEG) was synthesized and characterized for study of liver-specific targeting. From dynamic light scattering measurement, particle sizes of copolymeric nanoparticles were decreased with an increase of PEG in the copolymer. The morphology of GEG-3 nanoparticles observed by transmission electron micrograph was observed as almost spherical shapes and ranged about 50-300 nm. From the structural characterization using 1H nuclear magnetic resonance, both characteristic peaks of PBLG and PEG were visible in CDCl3 but the characteristic peaks of PBLG were invisible in D2O, indicating that GEG block copolymers are found to the core-shell type nanoparticles in water with PBLG innercore and PEG outershell, exposing that galactose moiety of GEG block copolymers are outerwards oriented on the nanoparticle surfaces. By galactose-specific aggregation test of particles using beta-galactose specific lectin, and flow cytometry measurement, specific interaction between asialoglycoprotein receptors (ASGPR) of HepG2, human hepatoma cell line, and galactose moieties of the GEG nanoparticles was confirmed. From cell cytotoxicity test, HepG2 cells with ASGPR are more sensitive to paclitaxel (TX)-loaded nanoparticles than free TX whereas, P388 cells, murine leukemia cell line, and SK-Hep 01, human hepatoma cell line, without ASGPR is less sensitive to TX-loaded nanoparticles than free TX, suggesting that specific interaction between HepG2 cells and galactose moiety of the nanoparticles occurred.

Animals↗

PubMed2005

Poly (4-vinylimidazole) as nonviral gene carrier: in vitro and in vivo transfection.

We explored poly(4-vinylimidazole) (P4V) as a nonviral gene carrier. We show that P4V can form DNA condensates of small size (<110 nm) using a dye-exclusion assay with ethidium bromide and dynamic light scattering, and that the complexes form in a pH-sensitive manner, due to the amphotericity of the polymer. P4V was demonstrated to lead to transfection in vitro as effectively as polyethyleneimine (PEI), but at lower cytotoxicity, under conditions where higher amounts of either polymer are required, using luciferase and green fluorescent protein as examples. Transfection in vivo was also explored, using a gene encoding yellow fluorescent protein and human osteoprotegerin injected in the tail vein of the rat. Transfection was observed, both at the gene and protein levels in lung and spleen tissue. Transfection in vivo appeared to be at least as effective using P4V as with PEI. Based upon this good transfection and low cytotoxicity, P4V seems to show promise as a nonviral gene transfer vector.

3T3 Cells↗

PubMed2005

Glucosylated polyethylenimine as a tumor-targeting gene carrier.

Glucosylated polyethylenimine (GPEI) was synthesized as a tumor-targeting gene carrier through facilitative glucose metabolism by tumor glucose transporter. Particle sizes of GPEI/DNA complex increased in proportion to glucose content of GPEI, whereas surface charge of the complex was not dependent on glucosylation, partially due to inefficient shielding of the short hydrophilic group introduced. GPEI with higher glucosylation (36 mol-%) had no cytotoxic effect on cells even at polymer concentrations higher than 200 microg/mL. Compared to unglucosylated PEI, glucosylation induced less than one-order decrease of transfection efficiency. Transfection of GPEI/DNA complex into tumor cells possibly occurred through specific interaction between glucose-related cell receptors and glucose moiety of GPEI. Gamma imaging technique revealed GPEI/DNA complex was distributed in liver, spleen, and tumors.

Carbohydrate Sequence↗

PubMed2005

Construction of a novel extracellular matrix using a new genetically engineered epidermal growth factor fused to IgG-Fc.

The design of artificial extracellular matrices has attracted much attention in tissue engineering as well as in cell biology research. An immobilized recombinant epidermal growth factor (EGF), fused to an immunoglobulin G (IgG) Fc region (abbreviated as EGF-Fc) has been constructed. Mouse fibroblast Swiss 3T3 cells adhered both to EGF-Fc-coated and collagen-coated surfaces. Phosphorylation of EGF receptor in A431 cells was induced by immobilized EGF-Fc as well as soluble EGF. Immobilized EGF-Fc continuously activated mitogen-activated protein kinase (MAPK) in A431 cells whereas MAPK activation induced by soluble EGF decreased rapidly with time. The cytoskeleton of A431 cells adhering onto immobilized EGF-Fc was filopodia whereas that of the cells adhering onto collagen in the presence of soluble EGF was lammellipodia.

Animals↗

PubMed2005

Alginate microcapsules prepared with xyloglucan as a synthetic extracellular matrix for hepatocyte attachment.

In this study, xyloglucan (XG) was used as a new synthetic extracellular matrix (ECM) for primary mouse hepatocyte attachment in Ca-alginate (AL) capsules. The rates of hepatocytes adhesion onto collagen type I-, XG-coated and uncoated polystyrene (PS) surface were 89.1%, 91.1% and 25.5%, respectively, at 4 h after incubation at 37 degrees C. From the inhibition study in a cell adhesion assay, the adhesion rates of freshly isolated hepatocytes and preincubated hepatocytes with 20 mm galactose onto the XG-coated surface were 55.7 and 17.3%, respectively, after 30 min incubation at 37 degrees C. Flow cytometric analysis showed that the internalization of XG by freshly isolated hepatocytes was stronger than preincubated hepatocytes with 20 mm galactose. The concentration of XG in AL/XG capsules to perform the best liver-specific functions was 0.5 mg/ml, where the highest albumin secretion rates were obtained. The albumin secretion, ammonia elimination rates and cell viability of hepatocytes were slowly decreased with culture time in AL/XG capsules, whereas those were rapidly decreased in AL capsules, indication of the more rapid formation of hepatocyte spheroids in AL/XG capsules than in AL capsules. More than 70% of the seeded hepatocytes in AL/XG capsules participated in spheroid formation after 2 days, whereas most hepatocytes in AL capsules remained as single cells and only a few cells began to form aggregates after 3 days. Intercellular molecule genes, such as connexin (Cx) 32 and E-cadherin, of hepatocyte spheroids in AL or AL/XG capsules were detected by reverse transcriptase-polymerase chain reaction. Cx32 and E-cadherin genes in AL/XG capsules were more rapidly reexpressed and expressed, respectively, than in AL ones. The results suggest that the multicellular spheroid formation of hepatocytes can enhance the liver-specific functions in the three-dimensional space in the presence of XG as a new synthetic ECM owing to the specific interaction between the galactose moieties of XG and asialoglycoprotein receptors of hepatocytes.

Alginates↗

PubMed2005

Polyethylene glycol (PEG) modified 99mTc-HMPAO-liposome for improving blood circulation and biodistribution: the effect of the extent of PEGylation.

Modification of liposomes using polyethylene glycol (PEG) results in steric hindrance to the phagocyte system and prolongation of blood circulation time. However, PEGylation can reduce radiolabeling efficiency (RE) when using the glutathione method for radiolabeling the liposomes. Therefore, we investigated the effect of the extent of PEGylation (PEG extent (PEGExt): 0, 5, 9.6, and 13.7 mol%) on the in vivo biodistribution of liposomes in Wistar rats, and RE with technetium-(99m) ((99m)Tc). PEGylated liposomes were prepared with egg phosphatidylcholine (egg PC, 1.85 mol%), cholesterol (1.0 mol%), and distearoylphosphatidylethanolamine-N-[polyethylene glycol] (DSPE-PEG; 0, 5, 9.6, and 13.7 mol%, respectively). The size distribution of the PEGylated liposomes was analyzed by a dynamic light scattering. The (99m)Tc-hexamethylpropylene-amine oxime ((99m)Tc-HMPAO) complexes were used for radiolabeling of preformed liposomes. The labeling efficiency and stability was analyzed with Sephadex G-15 column, and the biodistribution studies of (99m)Tc-liposomes after intravenous (i.v.) injection were also investigated with Wistar rats. The sizes of PEGylated liposomes decreased by increasing the PEGExt to 9.6 mol%, whereas sizes increased at 13.7 mol%. RE of (99m)Tc were greater than 90% for all PEGExt tested, and radiolabeling stability in human plasma was enhanced as a function of PEGExt. Liposomes without PEG were cleared rapidly from the blood and accumulated preferentially in the liver and the spleen. When PEGExt was increased, the accumulation in the organs decreased. This accumulation of PEG was maximized at 9.6 mol%. Accumulation of the liposomes in the spleen was increased again when PEGExt increased to 13.7 mol%. The splenic uptake of liposomes seemed to be dependent not only on PEGExt but also on the size of the liposomes. In conclusion, the PEG chains on the surface of liposome have no influence on the labeling efficiency, and the prolongation of circulation time was maximized at the 9.6 mol% of PEGylation.

Animals↗

PubMed2005

Hepatocyte-targeted nuclear imaging using 99mTc-galactosylated chitosan: conjugation, targeting, and biodistribution.

UNLABELLED: Galactosyl-methylated chitosan (GMC) is a galactosylated chitosan (GC) that is chemically modified to improve labeling efficiency with (99m)Tc compared with native GC. The aim of this study was to investigate the possibility of liver-targeted nuclear imaging with (99m)Tc-GMC bound to asialoglycoprotein receptors (ASGP-R). METHODS: GMC was obtained after the coupling of lactobionic acid, as the galactose moiety, and methyl iodide with chitosan. Using GMC-labeled fluorescein isothiocyanate (FITC-GMC), we examined whether GMC was localized in hepatocytes. After injection via the tail vein of mice with (99m)Tc-GMC and galactose-free (99m)Tc-methylated chitosan (MC), images were acquired with a gamma-camera equipped with a pinhole collimator. Biodistribution was obtained from 10, 60, and 120 min after injection. RESULTS: The composition of galactose groups in GC and tri-, di-, and monomethylated GC was confirmed by nuclear magnetic resonance spectroscopy. FITC-GMC was primarily positioned in hepatocytes, and not in Kupffer cells, of the mouse with a scattered pattern. The gamma-camera images showed rapid localization of (99m)Tc-GMC to liver. The percentage injected doses per gram (%ID/g) of liver were 11.155 +/- 2.332, 14.018 +/- 6.081, and 14.082 +/- 1.670 %ID/g (mean +/- SD) at 10, 60, and 120 min after injection, respectively. By contrast, galactose-free (99m)Tc-MC accumulated faintly in the liver. CONCLUSION: (99m)Tc-GMC specifically localized to the liver except for the kidneys in the mouse. GMC may be used to target the ASGP-R on the hepatocytes for nuclear imaging.

Animals↗

PubMed2004

Mucoadhesive microspheres prepared by interpolymer complexation and solvent diffusion method.

Mucoadhesive microspheres were prepared to increase gastric residence time using an interpolymer complexation of poly(acrylic acid) (PAA) with poly(vinyl pyrrolidone) (PVP) and a solvent diffusion method. The complexation between poly(acrylic acid) and poly(vinyl pyrrolidone) as a result of hydrogen bonding was confirmed by the shift in the carbonyl absorption bands of poly(acrylic acid) using FT-IR. A mixture of ethanol/water was used as the internal phase, corn oil was used as the external phase of emulsion, and span 80 was used as the surfactant. Spherical microspheres were prepared and the inside of the microspheres was completely filled. The optimum solvent ratio of the internal phase (ethanol/water) was 8/2 and 7/3, and the particle size increased as the content of water was increased. The mean particle size increased with the increase in polymer concentration. The adhesive force of microspheres was equivalent to that of Carbopol. The release rate of acetaminophen from the complex microspheres was slower than the PVP microspheres at pH 2.0 and 6.8.

Adhesives↗

PubMed2004

Galactosylated chitosan (GC)-graft-poly(vinyl pyrrolidone) (PVP) as hepatocyte-targeting DNA carrier: in vitro transfection.

Galactosylated chitosan-graft-poly(vinyl pyrrolidone) (GCPVP) was synthesized and characterized for hepatocyte-targeting gene carrier. GCPVP itself as well as GCPVP/DNA complex had negligible cytotoxicity regardless of the concentration of GCPVP and the charge ratio, but GCPVP/DNA complex had slightly cytotoxic effect on HepG2 cells only in the case of the higher charge ratio and 20 mM of Ca2+ concentration used. Through the confocal laser scanning microscopy, it is shown that the endocytosis by interaction between galactose ligands of GCPVP and ASGPR of the hepatocytes was the major route of transfection of GCPVP/F-plasmid complexes.

Animals↗

PubMed2004

Controlled release of Bordetella bronchiseptica dermonecrotoxin (BBD) vaccine from BBD-loaded chitosan microspheres in vitro.

Chitosan microspheres were prepared by ionic gelation process with sodium sulfate for nasal vaccine delivery. Bordetella Bronchiseptica Dermonecrotoxin (BBD) as a major virulence factor of a causative agent of atrophic rhinitis (AR) was loaded to the chitosan microspheres for vaccination. Morphology of BBD-loaded chitosan microspheres was observed as spherical shapes. The average particle sizes of the BBD-loaded chitosan microspheres were about 2.69 microm. More BBD was released with an increase of molecular weight of chitosan and with an increase of medium pH in vitro due to weaker intermolecular interaction between chitosan and BBD. Tumor necrosis factor-alpha (TNFalpha) and nitric oxide (NO) from RAW264.7 cells stimulated with BBD-loaded chitosan microspheres were gradually secreted, suggesting that released BBD from chitosan microspheres had immune stimulating activity of AR vaccine.

Animals↗