Sodium Periodate Concentration Research Articles

Study on flotation behavior and mechanism of galena flotation separation from chalcopyrite by sodium periodate depressant

The successful separating galena and chalcopyrite by flotation presents difficulties owing to their analogous surface chemical properties. This study investigated sodium periodate (SP) as a novel depressant for selectively oxidizing and modifying chalcopyrite and galena surfaces, enabling successful flotation separation. In micro-flotation tests were carried out at pH 8.5 and SP concentration of 5 × 10−4 mol/L. The grades of Cu and Pb in the copper concentrate were 27.87 % and 23.13 % with recoveries of 81.22 % and 27.78 %, respectively. SP selectively inhibited galena floatability while preserving chalcopyrite floatability. The selective depression mechanism research of SP in flotation separation process showed that galena surface hydrophobicity was significantly reduced by SP, which in turn prevented the collecting agent from adhering to galena. In the presence of SP, hydrophilic species such as PbSO4 and Pb(OH)2 were generated on the surface of galena, which decreased its ability to float. Conversely, on the chalcopyrite surface, hydrophobic products such as CuS2, CuSn, and S0 were formed, having little effect on its floatability. A model was developed to elucidate the mechanism underlying the selective flotation separation of the chalcopyrite and galena using SP.

Optimization of the Elasticity and Adhesion of Catechol- or Dopamine-Loaded Gelatin Gels under Oxidative Conditions.

The synthesis of surgical adhesives is based on the need to design glues that give rise to strong and fast bonds without cytotoxic side effects. A recent trend in surgical adhesives is to use gel-forming polymers modified with catechol groups, which can undergo oxidative crosslinking reactions and are strongly adhesive to all kinds on surfaces in wet conditions. We previously showed that blending gelatin with catechol can yield strong adhesion when the catechol is oxidized by a strong oxidant. Our previous work was limited to the study of the variation in the sodium periodate concentration. In this article, for an in-depth approach to the interactions between the components of the gels, the influence of the gelatin, the sodium periodate and dopamine/(pyro)catechol concentration on the storage (G′) and loss (G″) moduli of the gels, as well as their adhesion on steel, have been studied by shear rheometry. The hydrogels were characterized by infrared and UV-Vis spectroscopy and the size of their pores visualized by digital microscopy and SEM after freeze drying but without further additives. In terms of adhesion between two stainless steel plates, the optimum was obtained for a concentration of 10% w/v in gelatin, 10 mM in sodium periodate, and 20 mM in phenolic compounds. Below these values, it is likely that crosslinking has not been maximized and that the oxidizing environment is weakening the gelatin. Above these values, the loss in adhesiveness may result from the disruption of the alpha helixes due to the large number of phenolic compounds as well as the maintenance of an oxidizing environment. Overall, this investigation shows the possibility to design strongly adhesive hydrogels to metal surfaces by blending gelatin with polyphenols in oxidative conditions.

Synthesis and Characterization of Oxidized Polysaccharides for In Situ Forming Hydrogels.

Polysaccharides are widely used as building blocks of scaffolds and hydrogels in tissue engineering, which may require their chemical modification to permit crosslinking. The goal of this study was to generate a library of oxidized alginate (oALG) and oxidized hyaluronic acid (oHA) that can be used for in situ gelling hydrogels by covalent reaction between aldehyde groups of the oxidized polysaccharides (oPS) and amino groups of carboxymethyl chitosan (CMC) through imine bond formation. Here, we studied the effect of sodium periodate concentration and reaction time on aldehyde content, molecular weight of derivatives and cytotoxicity of oPS towards 3T3-L1 fibroblasts. It was found that the molecular weights of all oPs decreased with oxidation and that the degree of oxidation was generally higher in oHA than in oALG. Studies showed that only oPs with an oxidation degree above 25% were cytotoxic. Initial studies were also done on the crosslinking of oPs with CMC showing with rheometry that rather soft gels were formed from higher oxidized oPs possessing a moderate cytotoxicity. The results of this study indicate the potential of oALG and oHA for use as in situ gelling hydrogels or inks in bioprinting for application in tissue engineering and controlled release.

Recycling of pre-consumer viscose waste fibers for the removal of cationic dye from aqueous solution

Recycling of textile waste materials has attracted significant attention for fabrication low-cost dye adsorbent from aqueous solutions. Viscose cellulosic waste fibers are supposed to give an answer to the finding low-cost adsorbent materials. In this research work, viscose waste fibers (VF) were modified by selective oxidation to improve the ability to absorb cationic dyes during wastewater treatment. For this purpose, different treatment parameters were investigated such as sodium periodate concentration, and time of selective oxidation with sodium chlorite. Then, unmodified and oxidized viscose fibers (OVF) were ball milled to produce viscose powder (VP) and oxidized viscose powder (OVP), respectively. The morphology of obtained viscose powders was characterized by scanning electron microscopy. Furthermore, methylene blue adsorption onto viscose cellulose fiber waste (VF) and oxidized viscose fibers (OVF) was studied as a function of contact time (0–80 min), adsorbent dosage (1–9 g/L), MB solution initial pH (3–9) and MB initial concentration (20–80 mg/L). The results showed that MB adsorption onto VF and OVF is a rapid favorable chemisorption process that can be well described by the Langmuir model. The higher adsorption capacity of OVF than VF was related to the increase of the carboxylic group. The oxidized viscose fiber can be used as a potential adsorbent for water treatment.

Methods to prepare dopamine/polydopamine modified alginate hydrogels and their special improved properties for drug delivery

Dopamine (DA), a typical catechol-containing monomer, which has been well reported for its excellent applications in biomedical research, was used to modify alginate (ALG) hydrogel for better gel formation and performance which are needed for drug delivery. By our design, Polydopamine (PDA) particles embedded ALG hydrogel (ALG-PDA), two types of DA and ALG co-polymerized hydrogels (ALG-DA-AS, ALG-DA-SP) which were initiated by ammonia aqueous solution (AS) and sodium periodate (SP), respectively, were successfully prepared. The status of incorporated DA/PDA and their interactions with hydrogel skeleton were investigated by chemical structure, morphology and rheology characterizations. Interestingly, a self-gelation process was discovered during ALG-DA-SP preparation, which is supposed to be the crosslinking formation via the aromatic interaction and hydrogen bonding between catechol or o-benzoquinone modified ALG molecules. Such self-crosslinked structure was proved helpful to improve the structural stability of gel even in saline environment. The effects of DA, SP concentration on the self-gelation process were discussed. The good biocompatibility of PDA material was also confirmed by a cytotoxicity test. In loading and release experiments, all the modified hydrogels were proved to have better adsorption ability to gatifloxacin (GFLX) and more steady in vitro release behavior than pristine ALG hydrogel.

Chitosan: The One and Only? Aminated Cellulose as an Innovative Option for Primary Amino Groups Containing Polymers.

The aim of this study was the synthesis and in vitro characterization of aminated cellulose as alternative excipient to chitosan. The aldehyde form of cellulose was generated via the oxidative cleavage of vicinal diols by the addition of increasing concentrations of sodium periodate. The insertion of primary amines was achieved by reductive amination with ammonia. The degree of substitution was calculated via primary amino group quantification using a 2,4,6-trinitrobenzenesulfonic acid assay. Mucoadhesiveness was examined by adopting the rotating-cylinder method and tensile studies using porcine intestinal mucosa. Hydration was evaluated at pH 2-11. The successful formation of aldehydes as well as a subsequent introduction of up to 311.61 micromoles per gram of primary amines were proven to correlate with the amount of added periodate. There was a 3- to 14-fold prolongation in the mucosal residence time of the new polymer in comparison to chitosan, as measured by the rotating-cylinder method. Although cationic cellulose did not reach the maximum detachment force of chitosan, the total work of adhesion of the newly synthesized cellulose derivate was higher than that of chitosan. The higher the degree of amination, the higher the degree of hydration in neutral and alkaline aqueous media was. Compared to chitosan, the novel cationic cellulose derivative displays improved mucoadhesive properties as well as sufficient hydration at physiological pH. Therefore, aminated cellulose is a promising alternative to the cationic polymers, such as chitosan, used thus far.

Facile and Selective Determination of Dipeptides Using 3-Methylcatechol as a Novel Fluorogenic Reagent

Selective determination of peptides in mixtures or biological samples requires specific techniques for analysis. Herein, we report 3-methylcatechol (3-MC) as a novel fluorogenic reagent for the selective determination of dipeptides by a simple fluorescence (FL) derivatization reaction. After extensive screening of 31 different catechol analogues, 3-MC was found to generate FL with peptides. The reaction was performed at 100 °C for 10 min in the presence of borate buffer (pH 7) and sodium periodate. The resulting FL intensities were measured by spectrofluorometer at excitation wavelengths of 380 nm and emission wavelengths of 500 nm. Different reaction conditions such as concentration of sodium periodate, reaction time and pH of the borate buffer were studied to determine the optimum reaction conditions. Linearity was obtained between FL intensity and peptide concentrations from 10 to 160 µM with a lower detection limit of 10 µM (S/N = 3). Dipeptides containing Ala, Phe, Leu and Val at the N-termini generated significant FL in comparison to the reagent blank (**p < 0.005, ***p < 0.0005). The reaction is simple, rapid, selective and sensitive which can be applied for the determination of the dipeptides as biomarkers or to determine enzyme activity.

Natural dendrimers: Synthesis and in vitro characterization of glycogen-cysteamine conjugates

The aim of this study was to synthesize, characterize and evaluate the mucoadhesive properties of the first thiolated hyperbranched natural polysaccharide with biodegradability and biocompatibility features. In detail, glycogen-cysteamine conjugates were synthesized through a first step of oxidative ring opening applying increasing concentrations of sodium periodate, to obtain polymers with different degrees of oxidation, and a second step of reductive amination with a constant amount of cysteamine. The obtained glycogen-cysteamine conjugates were characterized regarding their content of free and total thiol groups by Ellman’s assay, biocompatibility, swelling/erosion behavior, rheological synergism and mucoadhesive properties in comparison to the unmodified glycogen. The higher the concentration of periodate was, the higher was the content of total thiol groups being in the range of 255.7±12–1194.5±82μmol/g, biocompatibility remained unaffected by these structural changes. On the contrary, the mucoadhesive properties, evaluated by tensile, rheological synergism and rotating cylinder studies, appear to be influenced by the thiol groups concentration on the glycogen. In particular the glycogen-cysteamine conjugate exhibiting the highest degree of thiolation showed a 79-fold increase in viscosity over a time period of 8h, as well as, remained attached on freshly excised porcine mucosa 32-fold longer than the unmodified polymer. The higher was the amount of conjugated thiol groups, the higher was the water absorption capacity of glycogen-cysteamine tablets in Simulated Intestinal Fluid pH 6.8 (SIF). The introduction of thiol moieties on polymer changed the characteristics of the polysaccharide by improving mucoadhesion properties. Therefore, this work represents the first study describing thiolated natural dendrimers as potential platform useful to realize appropriate mucoadhesive nanocarrier systems suitable to prolong mucosal residence time.

Covalent Binding of Antibodies to Cellulose Paper Discs and Their Applications in Naked-eye Colorimetric Immunoassays.

This report presents two methods for the covalent immobilization of capture antibodies on cellulose filter paper grade No. 1 (medium-flow filter paper) discs and grade No. 113 (fast-flow filter paper) discs. These cellulose paper discs were grafted with amine functional groups through a silane coupling technique before the antibodies were immobilized on them. Periodate oxidation and glutaraldehyde cross-linking methods were used to graft capture antibodies on the cellulose paper discs. In order to ensure the maximum binding capacity of the capture antibodies to their targets after immobilization, the effects of various concentrations of sodium periodate, glutaraldehyde, and capture antibodies on the surface of the paper discs were investigated. The antibodies that were coated on the amine-functionalized cellulose paper discs through a glutaraldehyde cross-linking agent showed enhanced binding activity to the target when compared to the periodate oxidation method. IgG (in mouse reference serum) was used as a reference target in this study to test the application of covalently immobilized antibodies through glutaraldehyde. A new paper-based, enzyme-linked immunosorbent assay (ELISA) was successfully developed and validated for the detection of IgG. This method does not require equipment, and it can detect 100 ng/ml of IgG. The fast-flow filter paper was more sensitive than the medium-flow filter paper. The incubation period of this assay was short and required small sample volumes. This naked-eye, colorimetric immunoassay can be extended to detect other targets that are identified with conventional ELISA.

Study on Preparation of Modified Cotton with Collagen

The surface modification process for cotton fabric which was oxidized first, and then crosslinked with collagen was studied. The optimum oxidation process was as follows: concentration of sodium periodate 0.6g/L, time 2.5h, temperature 40°C, ratio of water and cotton fabric was 100:1. The method for surface modification of cotton fabric was determined from comparative analysis, and the optimum process: collagen solution concentration 6%, glutaraldehyde concentration 5%, reaction 40min at 30°C, ratio of water and cotton fabric was 100:1. Compared with original cotton fabric,the breaking strength and elongation of collagen modified cotton fabric decreased, while the dyeing percentage with acid dyes was increased and this means the surface of modified cotton fabric was covered with a large component of collagen.

Cartilage regeneration using biodegradable oxidized alginate/hyaluronate hydrogels

Despite the widespread use of alginate (AL) hydrogels in many biomedical applications, including tissue engineering, AL is inherently non-degradable under physiological conditions. We hypothesized that degradable alginate (dAL) would be useful for cartilage regeneration when combined with hyaluronate (HA). We prepared dAL by partial oxidation of AL using sodium periodate, and the degradation rate of AL hydrogel was able to be regulated by control of sodium periodate concentration. The degradable oxidized AL/HA gels were formed in the presence of cells and their characteristics were investigated. dAL/HA gels with primary chondrocytes were injected subcutaneously into mice. Effective cartilage regeneration was observed after 6 weeks of transplantation based on histological analysis. Moreover, substantial secretion of sulfated glycosaminoglycans and expression of chondrogenic marker genes were also observed compared with non-dAL/HA gels. These results indicate that dAL/HA hydrogels may be useful in cartilage regeneration, and in many tissue engineering applications.

Degradation control of cellulose scaffold by Malaprade oxidation

ABSTRACTStudy on oxidizing cellulose scaffold to dialdehyde cellulose by sodium periodate (NaIO4) was carried out. Concentration of sodium periodate and the reaction time were effected for aldehyde introduction to cellulose scaffolds. Cellulose powder was dissolved in 1-butyl-3-methylimidazolium chloride, an ionic liquid, at 100°C and maintained at room temperature for 7 days, providing flexible cellulose scaffold. The cellulose scaffold was oxidized using periodate oxidation (Malaprade oxidation), which oxidizes carbohydrate by glycol cleavage to provide dialdehyde. Aldehyde groups introduced into cellulose were quantified by simple iodometry. Oxidized cellulose scaffold was degraded in the amino acid solution triggered by the reaction between aldehyde groups and amino groups. During immersion of the cellulose scaffolds in the amino acid solution, the mass loss of the scaffolds was evaluated by measuring of weight of oxidized cellulose scaffold before and after degradation.

Development of a hypersensitive periodate-cleavable amino acid that is methionine- and disulfide-compatible and its application in MHC exchange reagents for T cell characterisation.

Incorporation of cleavable linkers into peptides and proteins is of particular value in the study of biological processes. Here we describe the synthesis of a cleavable linker that is hypersensitive to oxidative cleavage as the result of the periodate reactivity of a vicinal amino alcohol moiety. Two strategies directed towards the synthesis of a building block suitable for solid-phase peptide synthesis were developed: a chemoenzymatic route, involving l-threonine aldolase, and an enantioselective chemical route; these led to α,γ-diamino-β-hydroxybutanoic acids in diastereoisomerically mixed and enantiopure forms, respectively. Incorporation of the 1,2-amino alcohol linker into the backbone of a peptide generated a conditional peptide that was rapidly cleaved at very low concentrations of sodium periodate. This cleavable peptide ligand was applied in the generation of MHC exchange reagents for the detection of antigen-specific T cells in peripheral blood cells. The extremely low concentration of periodate required to trigger MHC peptide exchange allowed the co-oxidation of methionine and disulfide residues to be avoided. Conditional MHC reagents hypersensitive to periodate can now be applied without limitations when UV irradiation is undesired or less practical.

METHYL CELLULOSE ENHANCE GELATIN MEMBRANE AS GUIDANCE CHANNELS FOR PERIPHERAL NERVE REGENERATION

Background: The methyl cellulose could successfully be transferred into 2,3-dialdehyde cellulose by using sodium periodate as an oxidant. 2,3-dialdehyde cellulose can cross-link gelatin without adding any other cross-linking agent. We hope the dialdehyde cellulose-gelatin membrane could enhance the physical properties of gelatin membrane by using glutaraldehyde as a cross-linker. Methods: The methyl cellulose could be successfully transferred into 2,3-dialdehyde cellulose by using sodium periodate as an oxidant. The biological stability of 2,3-dialdehyde cellulose was improved by cross-linking with gelatin. To estimate the properties of the DAC-Gel membrane with different conditions, the methyl cellulose was oxidized by different concentration of sodium periodate. After oxidized, the dialdehyde cellulose with different degree of oxidation was fabricated. FTIR could further confirm the formation of aldehyde group and the quantification of aldehyde group showed that the concentration of sodium periodate was the dominant factor to the degree of oxidation. Assessment of cross-linking degree helped us to observe the reaction between aldehyde group and amine group. The degradation test was estimated by two methods to confirm the accuracy of experiment. The hydrophilic/hydrophobic surface after cross-linking was evaluated by water contact angle test. The wettability of membrane influenced the growth of PC-12 cell. After the physical properties of membrane were established, the bio-compatibility was measured by two different methods. One of the methods based on ISO 10993. The other method is that cell seeding on the membrane. The bio-compatibility was evaluated by WST-1 and LDH. Result: Methyl cellulose was successfully converted into 2,3-dialdehyde cellulose by sodium periodate and the concentration of oxidant was the most important factor to the formation of aldehyde group. The formation of aldehyde group was directly proportional to the concentration of oxidant. Basic assessment of cross-linking degree showed that steric hindrance could be the factor to hinder cross-linking. The 2,3-dialdehyde cellulose/gelatin membrane could prolong the degradation time in 37°C. According to water contact test, the dialdehyde cellulose/gelatin membrane showed a more hydrophilic than gelatin membrane using glutaraldehyde as a cross-linker and the hydrophilic surface provided a better place for the growth of PC-12 cell. The dialdehyde cellulose/gelatin membrane using glycine to block the residual aldehyde group showed a low cytotoxicity. Conclusion: This study indicates that 2,3-dialdehyde cellulose/gelatin membrane could prolong the degradation time in 37°C and the 2,3-dialdehyde cellulose/gelatin membrane provide a better place for the growth of PC-12.

HEC-cysteamine conjugates: Influence of degree of thiolation on efflux pump inhibitory and permeation enhancing properties

Within the present study hydroxyethyl cellulose-cysteamine conjugates are investigated regarding biocompatibility, in situ gelling, permeation enhancing and efflux pump inhibitory properties. For this purpose, a series of concentrations of sodium periodate was prepared to oxidize HEC leading to ring opening of glucose subunits. The resulting polymers showing varying degrees of oxidation (DO) were then conjugated with cysteamine stabilized via reductive amination. Consequently, HEC-cysteamine conjugates with increasing degree in thiolation were obtained. Since the conjugates are positively charged, potency of cytotoxicity was tested by resazurin assay. In situ gelling properties of the conjugates were studied to investigate change of their viscosity due to inter- and/or intramolecular crosslinking via disulfide bonds. The influence of the presence of the conjugates on transport of rhodamine 123 and fluoresceinisothiocyanate-dextran 4 (FD4) representing model compounds for P-glycoprotein (P-gp) inhibition and permeation enhancing studies, respectively, across Caco-2 cell monolayers was determined. The conjugates showed a degree of thiolation in the range of 316–2158 μmol/g. Within 30 min, dynamic viscosity of the conjugate with the lowest degree of thiolation 0.5% (m/v) increased up to 300-fold. The conjugates showed a degree of thiolation-dependent increase in cytotoxicity but they all were found comparatively low cytotoxic. The addition of the conjugate with thiol group content of 1670 μmol/g resulted in the highest improvement in the transport of both rhodamine 123 and FD4 as compared to buffer control. Accordingly, the degree of thiolation strongly influences the properties of the conjugates and the modulation of the degree of thiolation could be exploited for development of various drug delivery systems.

Crosslinking Properties on Oxidized Cotton Cellulose and Chitosan with Low Molecular Weight

For exploiting green ecological cotton fiber products with the multifunction, a new cotton fiber crosslinked with chitosan of low molecular weight (CCCF) was prepared through the sodium periodate oxidation method. The reaction between amino groups of chitosan and aldehyde groups in the oxidized cotton cellulose occurred to obtain the CCCF in aqueous acetic acid solutions. The aldehyde group content in oxidized cotton cellulose increased markedly with the sodium periodate concentration, and the maximum weight gain of chitosan introduced on cotton fiber was 11.63% of the weight of cotton fibers. Furthermore, the crosslinking properties were respectively investigated by measurements of FT-IR and XPS spectra, the analysis indicated that the chitosan molecule was crosslinked on the surface of cotton fiber by the C=N covalent bond. This resulting CCCF is a novel ecological fiber and has more abilities of potential modification, which suggested useful information in planning applications for these modified cotton fibers.

Characterization and Physical Properties of Chitosan Modified Bamboo Pulp Fiber Fabric

With science and standard of living progressing, functional textile become more and more popular. We reported that a new bamboo pulp fiber fabric with the chitosan modification (CMBPFF) was prepared by the selective oxidation of sodium periodate and then treatment with a solution of chitosan aqueous acetic acid. The resulting CMBPFF is a nonpolluting and eco-friendly fabric product through the method of natural raw materials and no additives, which not only increase the added value of the product but also achieve natural ecological fabrics. This research using Kjeldahl nitrogen analysis showed that the maximum percentage of chitosan crosslinked on bamboo pulp fiber fabric was 10.52% (w/w). FT-IR spectra characterization suggested that the imine covalent bond between the chitosan and the oxidized bamboo pulp cellulose was formed through a series of reaction. The breaking strength of the modified fabric remained basically unchanged when the concentration of sodium periodate was less than 2.0 mg/ml. Furthermore, the chitosan modified bamboo pulp fiber fabric had the good antibacterial property. The wrinkle recovery angle and moisture regain of the chitosan modified fabric were improved. Meanwhile, a model experiment for the controlled release the drug was investigated using cactus extracts, a component of a Chinese medicine, indicated the extensive applicability of CMBPFF as a carrier for the controlled release drugs.

Effective inhibition of agglutinability of human A and B type erythrocytes by sodium periodate-chloroacetic acid combined treatment

The study focused on effective inhibition of the agglutinability of human A and B type erythrocytes by sodium periodate-chloroacetic acid concerted action. Suppression of agglutinability was determined by using anti-A and anti-B antisera. Effective concentrations of sodium periodate were 6.8 and 2.7 mM, respectively for A and B type erythrocytes in presence of 4.5 mg.ml-1 chloroacetic acid in the reaction mixture. Some major bio-physiological consequences of human erythrocytes including agglutination index, spontaneous red blood cell lysis percentage, zetapotential, morphology, surface functional groups (-OH, > C = O, -COOH) and semi-quantitative oxygen uptake and phagocytic uptake were also analyzed after the chemical treatments. The future work is directed towards the universal human erythrocytes preparation from A and B type human erythrocytes. Key words: ABH antibodies, agglutination, concerted action, erythrocyte, medicine, transfusion.

Protein A immobilization and HIgG adsorption onto porous/nonporous and swellable HEMA-incorporated polyEGDMA microspheres

Both non swellable and swellable poly(EGDMA/HEMA) microbeads were produced by suspension copolymerization. These microbeads were modified by immobilization of a spacer-arm (hexamethylene diamine (HMDA)) and protein A. The optimal values for modifications were as follows: sodium periodate concentration, 1.0 mg ml-1; HMDA concentration, 4 mg ml-1; and glutaraldehyde concentration, 0.070 μg ml-1. Adsorption of protein A onto the plain and periodate oxidized poly(EGDMA/HEMA) microbeads were very close to each other, and were 0.01-0.02 mg protein A on the 1-g Microbeads I and II, respectively. Protein A immobilization on poly(EGDMA/HEMA) microbeads were studied at different temperatures, times, and pHs using single protein solution containing different amounts of proteins. The optimal values for immobilization were as follows: the initial protein A concentration, 0.1 mg ml-1; temperature, 25°C; pH, 9.5; and immobilization time, 120 min. Incorporation of protein A resulted in 1.420 and 1.825 mg protein A on the 1-g Microbeads I and II, respectively. HIgG adsorption capacity on the protein A-incorporated poly(EGDMA/HEMA) microbeads is 27 and 35 mg HIgG g-1 polymer for Microbeads I and II, respectively.

Collagen Immobilization onto P(EGDMA/HEMA) Microbeads for Cell Affinity Systems

Both nonswellable and swellable poly(EGDMA/HEMA) microbeads were produced by suspension copolymerization. These microbeads were modified by immobilization of a spacer-arm (hexamethylene diamine, HMDA) and collagen. The optimal values for modifications were as follows: sodium periodate concentration: 0.467 × 10-2 mmol/mL; HMDA concentration: 3.5 × 10-2 mmol/mL; and glutaraldehyde concentration: 0.70 × 106 mmol/mL. Adsorption of collagen onto plain and periodate oxidized poly(EGDMA/HEMA) microbeads were similar, 0.25 and 0.50 mg collagen/g polymer, respectively. Collagen immobilization on poly(EGDMA/HEMA) microbeads was studied at various temperatures, times, and pH by using protein solution containing various amounts of proteins. The optimal values for immobilizations were as follows: the initial collagen concentration: 0.25 mg/mL; temperature: 4°C; pH 7; and the immobilization time; 120 min. Both fibroblastic 3T3 and epithelial MDBK cells were attached to these unmodified and modified microbeads. The attachments of 3T3 and MDBK cells, especially to the collagen immobilized swellable microbeads were very high. Almost 96% of the 3T3 cells available in the cell culture medium became attached to these microbeads (2297 ± 122 cells per mg of polymer). There was no significant effect by swelling on cell attachment.