• Polymer(Korea)
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• v.37 no.4
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• pp.539-546
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• 2013

Amino group-terminated poly(N-isopropylacrylamide) (PNIPAAm-$NH_2$) was synthesized via a radical polymerization of N-isopropylacrylamide (NIPAAm) using 2-aminoethanethiol hydrochloride (AESH) as a chain transfer agent. The molecular weight of the PNIPAAm-$NH_2$ was controlled by changing the concentration of AESH. The LCST of the aqueous solution of PNIPAAm-$NH_2$ increased slightly with increasing the AESH concentration. Alginate-g-PNIPAAm copolymer was synthesized by grafting PNIPAAm-$NH_2$ onto sodium alginate using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide and N-hydroxysuccinimide. The formation of the grafted copolymers was confirmed by FTIR spectroscopy, solubility in water, and SEM-EDS. Alginate-g-PNIPAAm also exhibited swelling-deswelling behavior. However, it showed a LCST at a slightly increased temperature compared to PNIPAAm. The swelling ratio of the alginate-g-PNIPAAm hydrogel increased with the increase of the grafted PNIPAAm content.

• Biomaterials and Biomechanics in Bioengineering
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• v.1 no.1
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• pp.1-12
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• 2014

Polymer multilayered hydrogels were prepared on a titanium alloy (Ti) substrate using a layer-by-layer (LBL) process to load a cell growth factor. Two water-soluble polymers were used to fabricate the multilayered hydrogels, a phospholipid polymer with both N, N-dimethylaminoethyl methacrylate (DMAEMA) units and 4-vinylphenylboronic acid (VPBA) units [poly(MPC-co-DMAEMA-co-VPBA) (PMDV)], and the polysaccharide alginate (ALG). PMDV interacted with ALG through a selective reaction between the VPBA units in PMDV and the hydroxyl groups in ALG and through electrostatic interactions between the DMAEMA units in PMDA and the anionic carboxyl groups in ALG. First, the Ti substrate was covered with photoreactive poly vinyl alcohol, and then the Ti alloy was alternately immersed in the respective polymer solutions to form the PMDV/ALG multilayered hydrogels. In this multilayered hydrogel, vascular endothelial growth factor (VEGF) was introduced in different layers during the LbL process under mild conditions. Release of VEGF from the multilayered hydrogels was dependent on the location; however, release continued for 2 weeks. Endothelial cells adhered to the hydrogel and proliferated, and these corresponded to the VEGF release profile from the hydrogel. We concluded that multilayered hydrogels composed of PMDV and ALG could be loaded with cell growth factors that have high activity and can control cell functions. Therefore, this system provides a cell function controllable substrate based on the controlled release of biologically active proteins.

• Bulletin of the Korean Chemical Society
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• v.30 no.8
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• pp.1817-1820
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• 2009

Controlling cell-matrix interactions is critical in regulating cell phenotypes for tissue engineering applications. Cellular adhesion to synthetic extracellular matrices (ECMs) can be enhanced by introduction of adhesion ligands to the matrices. We tested the hypothesis that biophysical cues such as ligand organization in synthetic ECMs play an important role in modulating cell responses to the microenvironment. To investigate and monitor cell-matrix interactions, we used a fluorescence resonance energy transfer (FRET) technique with cell-interactive polymers generated by conjugating a peptide with the sequence of arginine-glycine-aspartic acid (RGD) to alginate hydrogels.

• Proceedings of the Korean Society of Crop Science Conference
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• 2006.04a
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• pp.578-579
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• 2006

• Journal of Pharmaceutical Investigation
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• v.26 no.3
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• pp.187-192
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• 1996

The matrix tablet containing sodium alginate and $CaHPO_4$ can release drugs in a controlled fashion from hydrogel with gelling and swelling due to their interaction as water penetrates the matrices of the tablet. The purpose of this study was to evaluate release characteristics of the matrix tablet varying the amount of sodium alginate, $CaHPO_4$ and other excipients such as chitosan, hydroxypropyl methylcellulose (HPMC) and $Eudragit^{\circledR}$ RS100 in the simulated gastric and intestinal fluid. The practically soluble ibuprofen was used as a model drug. The release profiles of matrix tablet in the gastric fluid as a function of sodium alginate/$CaHPO_4$ ratio was not pronounced because of low solubility of drug and stability of alginate matrices. However, release rate of drug from the matrix tablet in the intestinal fluid was largely changed when sodium alginate/$CaHPO_4$ ratio was increased, suggesting that the ratio of sodium alginate/$CaHPO_4$ was an important factor to control the gelling and swelling of the matrix tablet. The incorporation of other excipients into the matrix tablet also influenced the release rate of drug. The chitosan and HPMC decreased the release rate of drug. No release of drug was occurred when $Eudragit^{\circledR}$ RS100 was added into the tablet. The retarded release of matrix tablet when excipients were added resulted from the hindrance of swelling and gelling of the matrix tablet containing sodium alginate and $CaHPO_4$. The hardness and bulk density of the matrix tablet was not correlated with release rate of drug in the study. From these findings, the ratio of sodium alginate and $CaHPO_4$ in the matrix tablet in addition to incorporation of excipients could be very important to control the release rate of drug in dosage form design.

• The Journal of Korean Obstetrics and Gynecology
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• v.25 no.1
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• pp.1-10
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• 2012

Purpose: This study was conducted to evaluate the inhibitory effect of Achyranthis Radix extract(ARE) loaded hydrogel on osteoclast differentiation. Methods: MTT-assay was performed to estimate cytotoxicity of ARE, Achyranthis Radix-alginate hydrogel disk(ARHD) in bone marrow macrophages stimulated(BMMs) with human receptor activator of nuclear factor-${\kappa}B$ ligand(RANKL), human macrophage-colony stimulating factor(M-CSF). Tartrate resistant acid phosphatase staining and RT-PCR were performed to know the inhibitory effect on osteoclast differentiation. Reactive oxygen species and actin ring formation were analysed to observe the effect of ARHD. Results: ARE has no cytotoxicity at the concentration of 0.1 $mg/m{\ell}$ or lower. ARE decreased the number of TRAP positive cells in RANKL, M-CSF stimulated BMMs and the gene expression. ARHD has no cytotoxicity at the concentration of 10 ${\mu}g/m{\ell}$ (24, 48hours), 50 ${\mu}g/m{\ell}$ (24 hours). ARHD restrained the synthesis of reactive oxygen species and the formation of actin ring. Conclusions: Achyranthis Radix has the inhibitory effect of osteoclast differentiation and bone resorption. Further studies are needed to treat osteoporosis by Achyranthis Radix.

• Journal of the Korean Chemical Society
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• v.61 no.6
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• pp.352-358
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• 2017

The addition of alginic acid, a natural polysaccharide, to improve the wettability and the reduction of protein adsorption of hydrogel contact lenses. Hydrogel contact lenses were manufactured with various monomers such as 2-methacryloyloxyethyl phosphorylcholine (MPC) and NVP (N-Vinyl-2-pyrrolidone). Alginic acid was added by by the initial mixing method and the interpenetrating polymer networks(IPN) method. Properties of contact lens such as contact angle, oxygen permeability, and protein adsorption amount were evaluated. The oxygen permeability and wettability of the IPN-treated alginate samples were higher than those of the samples that were not treated with IPN. The physical properties were improved as the concentration of IPN-treated alginic acid increased. Protein adsorption decreased by the addition of alginic acid and further decreased with IPN. In particular, contact lenses containing MPC and NVP significantly decreased protein adsorption. Therefore, the effect of alginate on the functional improvement of contact lens was confirmed.

• Korean Journal of Chemical Engineering
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• v.35 no.12
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• pp.2384-2393
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• 2018

Porous alginate-based hydrogel beads (porous ABH) have been prepared through a facile and sustainable template-assisted method using nano-calcium carbonate and nano-$CaCO_3$ as pore-directing agent for the efficient capture of methylene blue (MB). The materials were characterized by various techniques. The sorption capacities of ABH towards MB were compared with pure sodium alginate (ABH-1:0) in batch and fixed-bed column adsorption studies. The obtained adsorbent (ABH-1:3) has a higher BET surface area and a smaller average pore diameter. The maximum adsorption capacity of ABH-1:3 obtained from Langmuir model was as high as $1,426.0mg\;g^{-1}$. The kinetics strictly followed pseudo-second order rate equation and the adsorption reaction was effectively facilitated, approximately 50 minutes to achieve adsorption equilibrium, which was significantly shorter than that of ABH-1:0. The thermodynamic parameters revealed that the adsorption was spontaneous and exothermic. Thomas model fitted well with the breakthrough curves and could describe the dynamic behavior of the column. More significantly, the uptake capacity of ABH-1:3 was still higher than 75% of the maximum adsorption capacity even after ten cycles, indicating that this novel adsorbent can be a promising adsorptive material for removal of MB from aqueous solution under batch and continuous systems.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.4
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• pp.583-587
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• 2020

Imitation fish roe (IFR) based on calcium alginate hydrogels (CAG) can be heat treated for sterilization and salted to prolong the shelf life. However, these processes change the physical properties of IFR, and it is necessary to minimize these changes. In this study, we investigated the effects of xanthan gum (XG) treatment on the quality and stability of IFR. Both non-XG and XG-treated IFRs were treated with boiling water (95℃), sodium chloride (0.5-2.0%, w/v), and autoclaving. The non-XG treated IFR shrunk slightly after the boiling water and autoclaving processes. By comparison, shrinkage of the XG-treated IFR after autoclaving was significantly reduced. The sphericity of the non-XG treated IFR was reduced by the boiling water, sodium chloride, and autoclaving treatment. However, the sphericity of the XG-treated IFR was maintained by 90% or more, preserving the IFR shape at a level visually recognized as spherical. In addition, unlike the non-XG treated IFR, the XG-treated IFR showed high rupture strength even after the salt and heat treatments. Our findings provide useful information for the industrialization of IFR based on CAG with heat and salt treatments.

• Polymer(Korea)
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• v.25 no.4
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• pp.476-485
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• 2001

In this study, we tried to design and synthesize using natural polymers (hyaluronic acid and sodium alginate) and also to make some kinds of scaffolds as sponge type for reducing the burst effect of loaded drug from them. Photo-dimerizable group was incorporated to hyaluronic acid and degradable hydrogel was prepared by the UV radiation of the polymer. The pore size and its distribution of scaffold were controlled by changing microsphere production conditions such as solution concentration and spraying pressure. It was found that drug release behavior from synthesized scaffolds was affected by hybridization of two naturally originated polymers (cinnamoylated tetrabutylammonium hyaluronate: CHT and cinnamolylated sodium alginate: CSA) and the obtained scaffolds were degraded in fairly long time (about 2 months) under in vitro environment. Therefore, we expect that obtained scaffolds can be applicable for the tissue regeneration scaffolds in the fields of orthopaedic surgery.