Human serum albumin adsorption on poly[(glycidyl methacrylate)‐co‐(methyl methacrylate)] beads modified with a spacer‐arm‐attached L‐histidine ligand

Poly(GMA/MMA) beads were synthesized from glycidyl methacrylate (GMA) and methyl methacrylate (MMA) in the presence of a cross‐linker (i.e. ethyleneglycol dimethacrylate) (EGDMA) via suspension polymerization. The epoxy groups of the poly(GMA/MMA) beads were converted into amino groups with either ammonia or 1,6‐diaminohexane (i.e. spacer‐arm). An L ‐histidine ligand was then covalently immobilized on the aminated (poly(GMA/MMA)‐AH) and/or the spacer‐arm attached (poly(GMA/MMA)‐SAH) beads using glutaric dialdehyde as a coupling agent. Both affinity adsorbents were used in human serum albumin (HSA) adsorption/desorption studies under defined pH, ionic strength or temperature conditions in a batch reactor. The spacer‐arm attached affinity adsorbent resulted in an increase in the adsorption capacity to HSA when compared to the aminated counterpart (i.e. poly(GMA/MMA)‐AH). The maximum adsorption capacities of the affinity adsorbents were found to be significantly high, i.e. 43.7 and 80.2 mg g^?1 (of the beads), while the affinity constants, evaluated by the Langmuir model, were 3.96 × 10^?7 and 9.53 × 10^?7 mol L^?1 for poly(GMA/MMA)‐AH and poly(GMA/MMA)‐SAH, respectively. The adsorption capacities of the affinity adsorbents were decreased for HSA by increasing the ionic strength, adjusted with NaCl. The adsorption kinetics of HSA were analysed by using pseudo‐first and pseudo‐second‐order equations. The second‐order equation fitted well with the experimental data. Copyright © 2005 Society of Chemical Industry     

Adsorption of IgG on spacer‐arm and L‐arginine ligand attached poly(GMA/MMA/EGDMA) beads

This work presents data on human immunoglobulin G (HIgG) adsorption onto L ‐arginine ligand attached poly(GMA/MMA/EGDMA)‐based affinity beads which were synthesized from methyl methacrylate (MMA) and glycidiyl methacrylate (GMA) in the presence of a crosslinker (i.e., ethylene glycol dimethacrylate; EGDMA) by suspension polymerization. The epoxy groups of the poly(GMA/MMA/EGDMA) beads were converted into amino groups after reaction with ammonia or 1,6‐diaminohexane (i.e., spacer‐arm). With L ‐arginine as a ligand, it was covalently immobilized on the aminated (poly(GMA/MMA/EGDMA)‐ AA) and/or the spacer‐arm attached (poly(GMA/MMA/EGDMA)‐SA) beads, using glutaric dialdehyde as a coupling agent. Both affinity poly(GMA/MMA/EGDMA)‐based beads were used in HIgG adsorption/desorption studies under defined pH, ionic strength, or temperature conditions in a batch reactor, using acid‐treated poly(GMA/MMA/EGDMA) beads as a control system. The poly(GMA/MMA/EGDMA)‐SA affinity beads resulted in an increase in the adsorption capacity to HIgG compared with the aminated counterpart (i.e., poly(GMA/MMA/EGDMA)‐AA). The maximum adsorption capacities of the poly(GMA/MMA/EGDMA)‐AA and poly(GMA/MMA/EGDMA)‐SA affinity beads were found to be 112.36 and 142 mg g^?1, and the affinity constants (K_d), evaluated by the Langmuir model, were 2.48 × 10^?7 and 6.98 × 10^?7M, respectively. Adsorption capacities of the poly(GMA/MMA/EGDMA)‐AA and poly(GMA/MMA/EGDMA)‐SA were decreased with HIgG by increasing the ionic strength adjusted with NaCl. Adsorption kinetic of HIgG onto both affinity adsorbents was analyzed with first‐ and second‐order kinetic equations. The first‐order equation fitted well with the experimental data. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 672–679, 2007     

Improved synthesis of a branched poly(ethylene imine)‐modified cellulose‐based adsorbent for removal and recovery of Cu(II) from aqueous solution

This study focuses on an improved synthesis of a branched poly (ethylene imine) (PEI)‐modified cellulose‐based adsorbent (Cell‐g‐PGMA‐PEI). We aim to improve the adsorbent capacity by reducing side reaction of epoxide ring opening during graft copolymerization of glycidyl methacrylate (GMA) onto cellulose which increases the content of epoxy groups, anchors to immobilize branched PEI moieties. FTIR spectra provided the evidence of successful graft copolymerization of GMA onto cellulose initiated by benzoyl peroxide (BPO) and modification with PEI. The amount of epoxy groups of Cell‐g‐PGMA was 4.35 mmol g^?1 by epoxy titration. Subsequently, the adsorption behavior of Cu(II) on cell‐g‐PGMA‐PEI in aqueous solution has been investigated. The data from the adsorption kinetic experiments agreed well with pseudo‐second‐order model. The adsorption isotherms can be interpreted by the Langmuir model with the maximum adsorption capacity of 102 mg g^?1 which was largely improved compared with the similar adsorbent reported. The dynamic adsorption capacity obtained from the column tests was 119 mg g^?1 and the adsorbent could be regenerated by HCl of 0.1 mol L^?1. Results indicate that the novel pathway for the synthesis of Cell‐g‐PGMA‐PEI exhibits significant potential to improve the performance of adsorbents in removal and recovery of Cu(II) from aqueous solution. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation of polymer‐supported polyethylene glycol and phase‐transfer catalytic activity in benzoate synthesis

The crosslinked polymeric microspheres (GMA/MMA) of glycyl methacrylate (GMA) and methyl methacrylate (MMA) were prepared by suspension polymerization. Polyethylene glycol (PEG) was grafted on GMA/MMA microsphers via the ring‐opening reaction of the epoxy groups on the surfaces of GMA/MMA microspheres, forming a polymer‐supported triphase catalyst, PEG‐GMA/MMA. The Phase‐transfer catalytic activity of PEG‐GMA/MMA microspheres was evaluated using the esterification reaction of n‐chlorobutane in organic phase and benzoic acid in water phase as a model system. The effects of various factors on the phase transfer catalysis reaction of liquid–solid–liquid were investigated. The experimental results show that the PEG‐GMA/MMA microspheres are an effective and stable triphase catalyst for the esterification reaction carried out between oil phase and water phase. The polarity of the organic solvent, the ratio of oil phase volume to water phase volume and the density of the grafted PEG on PEG‐GMA/MMA microspheres affect the reaction rate greatly. For this investigated system, the solvent with high polarity is appropriate, an adequate volume ratio of oil phase to water phase is 2:1, and the optimal PEG density on the polymeric microspheres is 15 g/100 g. Triphase catalysts offer many advantages associated with heterogeneous catalysts such as easy separation from the reaction mixture and reusability. The activity of PEG‐GMA/MMA microspheres is not nearly decreased after reusing of 10 recycles. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

Preparation of grafted polytetrafluoroethylene fibers and adsorption of bilirubin

BACKGROUND: A successful hemoperfusion technique requires that the adsorbent for bilirubin should have a high specificity, adsorption capacity and adsorption rate, blood compatibility and no toxicity. Compared with polymer microbeads, polytetrafluoroethylene (PTFE) fibers have many advantages. The aim of the work reported here was to prepare a new polytetrafluoroethylene‐graft‐poly(glycidyl methacrylate)‐block‐polyethyleneimine (PTFE‐g‐PGMA‐b‐PEI) adsorbent for bilirubin based on PTFE fibers by the ⁶⁰Co radiation‐induced graft polymerization of GMA followed by the chemical modification of the epoxy groups on the PTFE‐g‐PGMA fibers with PEI. In addition, the adsorption properties of this novel adsorbent for bilirubin were examined. RESULTS: The highest content of amino groups obtained on the PTFE‐g‐PGMA‐b‐PEI fibers was 1.87 mmol g^?1. The maximum adsorption capacity of the grafted fibers was 9.6 mg g^?1 at pH = 6.5. Bilirubin adsorption on these fibers obeyed the Langmuir model. Also, these fibers possessed the ability to selectively adsorb bilirubin in the presence of bovine serum albumin. CONCLUSION: The PTFE‐g‐PGMA‐b‐PEI fibers have a high adsorption capacity for bilirubin and excellent adsorption properties. In addition, this new adsorbent is inexpensive, easy to prepare and has no toxicity. So the PTFE‐g‐PGMA‐b‐PEI fibers as a biomedical adsorbent are promising for the removal of bilirubin through the hemoperfusion technique. Copyright © 2009 Society of Chemical Industry     

Nonporous monosize polymeric sorbents: Dye and metal chelate affinity separation of lysozyme

Lysozyme adsorption onto dye‐attached nonporous monosize poly(2‐hydroxyethyl‐methacrylate‐methylmethacrylate) [poly(HEMA‐MMA)] microspheres was investigated. Poly(HEMA‐MMA) microspheres were prepared by dispersion polymerization. The monochloro‐triazine dye, Cibacron Blue F3GA, was immobilized covalently as dye–ligand. These dye‐affinity microspheres were used in the lysozyme adsorption–desorption studies. The effect of initial concentration of lysozyme and medium pH on the adsorption efficiency of dye‐attached and metal‐chelated microspheres were studied in a batch reactor. Effect of Cu(II) chelation on lysozyme adsorption was also studied. The nonspecific adsorption of lysozyme on the poly(HEMA‐MMA) microspheres was 3.6 mg/g. Cibacron Blue F3GA attachment significantly increased the lysozyme adsorption up to 247.8 mg/g. Lysozyme adsorption capacity of the Cu(II) incorporated microspheres (318.9 mg/g) was greater than that of the Cibacron Blue F3GA‐attached microspheres. Significant amount of the adsorbed lysozyme (up to 97%) was desorbed in 1 h in the desorption medium containing 1.0M NaSCN at pH 8.0 and 25 mM EDTA at pH 4.9. In order to examine the effects of separation conditions on possible conformational changes of lysozyme structure, fluorescence spectrophotometry was employed. We conclude that dye‐ and metal‐chelate affinity chromatography with poly(HEMA‐MMA) microspheres can be applied for lysozyme separation without causing any significant changes and denaturation. Repeated adsorption/desorption processes showed that these novel dye‐attached monosize microspheres are suitable for lysozyme adsorption. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 115–124, 2000     

Synthesis and characterization of magnetic beads containing aminated fibrous surfaces for removal of Reactive Green 19 dye: kinetics and thermodynamic parameters

BACKGROUND: Poly(HEMA‐co‐MMA) beads were prepared from 2‐hydroxyethyl‐methacrylate (HEMA) and methylmethacrylate (MMA) in the presence of FeCl₃. Thermal co‐precipitation of Fe(III) ions containing beads with Fe(II) ions was carried out under alkaline conditions. The magnetic beads were grafted with poly(glycidylmethacrylate; p(GMA)), and the epoxy groups of the grafted p(GMA) brushes were converted into amino groups by reaction with ammonia. RESULTS: The magnetic beads were characterized by surface area measurement, electron spin resonance (ESR), Mössbauer spectroscopy and scanning electron microscopy (SEM). The maximum adsorption of Reactive Green‐19 (RG‐19) dye on the p(GMA) grafted and amine modified magnetic beads was around pH 3.0. The adsorption capacity of magnetic beads was 84.6 mg dye g^?1. The effects of adsorbent dosage, ionic strength and temperature have also been reported. Batch kinetic sorption experiments showed that a pseudo‐second‐order rate kinetic model was applicable. CONCLUSION: The p(GMA) grafted and amine modified magnetic beads (adsorbent) were expected to have the advantage of mobility of the grafted chains in the removal of acidic dyes from aqueous solutions. The magnetic beads have potential as an adsorbent for removal of pollutants under various experimental conditions without significant reduction in their initial adsorption capacity. Copyright © 2011 Society of Chemical Industry     

N‐acetyl‐D‐galactosamine‐specific lectin isolation from soyflour with poly(HPMA‐GMA) beads

Soybean lectin was purified from seeds of Glycine max L.Merrill SA88. Poly(hydroxypropyl methacrylate‐glycidyl methacrylate) [poly(HPMA‐GMA)] beads were used as an affinity matrix and N‐acetyl‐D ‐galactosamine (GalNAc) was used as an affinity ligand. Soybean lectin adsorption with GalNAc attached poly(HPMA‐GMA) beads from soybean lectin solution (in phosphate buffered saline) was 5.0 mg/g. Maximum adsorption capacity for soybean lectin from the soy flour extract was 26.0 mg/g. Elution of soybean lectin from adsorbent was accomplished by 0.5M galactose solution. Purity of soybean lectin was determined by SDS‐PAGE. It was observed that soybean lectin could be repeatedly adsorbed and desorbed with GalNAc‐attached poly(HPMA‐GMA) beads. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Adsorption of heavy‐metal ions on poly(ethylene imine)‐immobilized poly(methyl methacrylate) microspheres

Poly(methyl methacrylate) (PMMA) microspheres carrying poly(ethylene imine) (PEI) were prepared for the removal of heavy‐metal ions (copper, cadmium, and lead) from aqueous solutions with different amounts of these ions (50–600 mg/L) and different pH values (3.0–7.0). Ester groups in the PMMA structures were converted to imine groups in a reaction with PEI as a metal‐chelating ligand in the presence of NaH. The adsorption of heavy‐metal ions on the unmodified PMMA microspheres was very low [3.6 μmol/g for Cu(II), 4.6 μmol/g for Cd(II), and 4.2 μmol/g for Pb(II)]. PEI immobilization significantly increased the heavy‐metal adsorption [0.224 mmol/g for Cu(II), 0.276 mmol/g for Cd(II), and 0.126 mmol/g for Pb(II)]. The affinity order of adsorption (in moles) was Cd(II) > Cu(II) > Pb(II). The adsorption of heavy‐metal ions increased with increasing pH and reached a plateau value around pH 5.5. Their adsorption behavior was approximately described with the Langmuir equation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 197–205, 2001     

Affinity adsorption of recombinant human interferon‐α on monosize dye‐affinity beads

Monosize, nonporous poly(glycidyl methacrylate) [poly(GMA)] beads were prepared by dispersion polymerization. Cibacron Blue F3GA was covalently attached onto the poly(GMA) beads for adsorption of recombinant interferon‐α (rHuIFN‐α). Monosize poly(GMA) beads were characterized by scanning electron microscopy. Dye‐carrying beads (1.73 mmol/g) were used in the adsorption–elution studies. The effect of initial concentration of rHuIFN‐α, pH, ionic strength, and temperature on the adsorption efficiency was studied in a batch system. Nonspecific adsorption of rHuIFN‐α on the beads was 0.78 mg/g. Dye attachment significantly increased the rHuIFN‐α adsorption up to 181.7 mg/g. Equilibrium adsorption of rHuIFN‐α onto the dye‐carrying beads increased with increasing temperature. Negative change in free energy (ΔG⁰ < 0) indicated that the adsorption was a thermodynamically favorable process. ΔS and ΔH values were 146.1 J/mol K and ?37.39 kJ/mol, respectively. Significant amount of the adsorbed rHuIFN‐α (up to 97.2%) was eluted in the elution medium containing 1.0M NaCl in 1 h. To determine the effects of adsorption conditions on possible conformational changes of rHuIFN‐α structure, fluorescence spectrophotometry was employed. We concluded that dye‐affinity beads can be applied for rHuIFN‐α adsorption without causing any significant conformational changes. Repeated adsorption–elution processes showed that these beads are suitable for rHuIFN‐α adsorption. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 975–981, 2007     

Highly efficient adsorbent for organic dyes based on a temperature‐ and pH‐responsive multiblock polymer

The self‐assembly behavior of amphiphilic block copolymers in selective solutions has many applications in environmentally responsive polymer materials. In this article, we report on a new amphiphilic, temperature and pH dual‐responsive poly[2‐dimethylaminoethyl methacrylate‐co‐(methyl methacrylate)]‐b‐poly[poly(ethylene glycol) methacrylate] [P(DMAEMA‐co‐MMA)‐b‐PPEGMA], which was synthesized via reversible addition–fragmentation chain‐transfer polymerization. The structure, self‐assembly behaviors, and process of organic dye adsorption were characterized by ¹H‐NMR, ultraviolet–visible absorbance spectroscopy, and DLS measurements. P(DMAEMA‐co‐MMA)‐b‐PPEGMA was proven to be an outstanding adsorbent with excellent reversibility. Methyl red was released from the micelles as the pH value of the solution was adjusted to 4, and it could also be encapsulated again when the pH value was adjusted to 7.4 because of the sensitive pH‐responsive ability. It is promising that the triblock polymer had a positive effect on dye adsorption for environmental protection. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46626.     

Preparation and characterization of magnetic poly(styrene–glycidyl methacrylate) microspheres for highly efficient protein adsorption by two‐stage dispersion polymerization

Micrometer‐sized superparamagnetic poly(styrene–glycidyl methacrylate)/Fe₃O₄ spheres were synthesized by two‐stage dispersion polymerization with modified hydrophobic Fe₃O₄ nanoparticles, styrene (St), and glycidyl methacrylate (GMA). The morphology and properties of the magnetic Fe₃O₄–P (St‐GMA) microspheres were examined by scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, thermogravimetric analysis, and attenuated total reflectance. The average size of the obtained magnetic microspheres was 1.50 μm in diameter with a narrow size distribution, and the saturation magnetization of the magnetic microspheres was 8.23 emu/g. The magnetic Fe₃O₄–P (St‐GMA) microspheres with immobilized iminodiacetic acid–Cu²⁺ groups were used to investigate the adsorption capacity and selectivity of the model proteins, bovine hemoglobin (BHb) and bovine serum albumin (BSA). We found that the adsorption capacity of BHb was as high as 190.66 mg/g of microspheres, which was 3.20 times greater than that of BSA, which was only 59.64 mg/g of microspheres as determined by high‐performance liquid chromatography. With a rather low nonspecific adsorption, these microspheres have great potential for protein separation and purification applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43005.     

Human serum albumin (HSA) adsorption with chitosan microspheres

In this study, chitosan microspheres were prepared and characterized for adsorption of human serum albumin (HSA) as affinity sorbent. The chitosan microspheres were obtained with a “suspension crosslinking technique” in the size range of 30–700 μm by using a crosslinker, i.e., glutaraldehyde. The chitosan microspheres used in HSA adsorption studies were having the average size of 170 ± 81 μm. Adsorption medium pH and the initial HSA concentration in the adsorption medium were changed as 4.0–7.0 and 0.5–2.0 mg HSA/mL, respectively, to investigate the HSA adsorption capacity of chitosan microspheres. Maximum HSA adsorption (i.e., 11.35 mg HSA/g chitosan microspheres) was obtained at pH 5.0 and 1.5 mg HSA/mL of the initial HSA concentration in the adsorption medium was obtained as the saturation value for HSA adsorption. A very common dye ligand, i.e., Cibacron Blue F3GA was attached to the chitosan microspheres to increase the HSA adsorption capacity. Actually, the HSA adsorption capacity was increased up to 15.35 mg HSA/g chitosan microspheres in the case of Cibacron Blue F3GA attached to chitosan microspheres used. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3035–3039, 2002     

Synthesis of monodisperse nonporous crosslinked poly(glycidyl methacrylate) particles with metal affinity ligands for protein adsorption

Monodisperse nonporous crosslinked poly(glycidyl methacrylate) (PGMA) particles with immobilized metal affinity ligands were prepared for selective recovery of proteins. The PGMA particles, with an average size of 2.2 µm, were prepared by a simple dispersion polymerization of glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA). The particles were characterized by scanning electron microscopy (SEM) and Fourier‐transform infrared spectroscopy (FTIR). The epoxy groups of the particles were modified with the metal chelating agent iminodiacetic acid (IDA), which forms metal–IDA chelates at the active sites. After charging with copper ions, the particles were used to recover a model protein, bovine hemoglobin (BHb), in a batchwise manner. The particles had the adsorption capacity of 218.7 mg g⁻¹ with little nonspecific adsorption. The adsorption behavior could be described with the Langmuir equation. The effect of pH on the adsorption was also studied. Regeneration of the metal‐chelated particles was easily performed with 50 mmol L⁻¹ ethylenediaminetetraacetic acid (EDTA), followed by washing with water and reloading with Cu²⁺. The particles could be very useful as an affinity separation adsorbent. Copyright © 2005 Society of Chemical Industry     

Poly(vinylbenzylchloride) beads grafted with polymer brushes carrying hydrazine ligand for reversible enzyme immobilization

Poly(glycidylmethacrylate), p(GMA), brush grafted poly(vinylbenzyl chloride/ethyleneglycol dimethacrylate), p(VBC/EGDMA), beads were prepared by suspension polymerization and the beads were grafted with poly(glycidyl methacrylate), p(GMA), via surface‐initiated atom transfer radical polymerization aiming to construct a material surface with fibrous polymer. The epoxy groups of the fibrous polymer were reacted with hydrazine (HDZ) to create affinity binding site on the support for adsorption of protein. The influence of pH, and initial invertase concentration on the immobilization capacity of the p(VBC/EGDMA‐g‐GMA)‐HDZ beads has been investigated. Maximum invertase immobilization onto hydrazine functionalized beads was found to be 86.7 mg/g at pH 4.0. The experimental equilibrium data obtained invertase adsorption onto p(VBC/EGDMA‐g‐GMA)‐HDZ affinity beads fitted well to the Langmuir isotherm model. It was shown that the relative activity of immobilized invertase was higher than that of the free enzyme over broader pH and temperature ranges. The K_m and V_max values of the immobilized invertase were larger than those of the free enzyme. After inactivation of enzyme, p(VBC/EGDMA‐g‐GMA)‐HDZ beads can be easily regenerated and reloaded with the enzyme for repeated use. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Cibacron Blue F3GA‐attached magnetic poly(2‐hydroxyethyl methacrylate) beads for human serum albumin adsorption

An affinity dye ligand, Cibacron Blue F3GA, was covalently attached onto magnetic poly(2‐hydroxyethyl methacrylate) (mPHEMA) beads for human serum albumin (HSA) adsorption from both aqueous solutions and human plasma. The mPHEMA beads, in the size range of 80 to 120 µm, were prepared by a modified suspension technique. Cibacron Blue F3GA molecules were incorporated on to the mPHEMA beads. The maximum amount of Cibacron Blue F3GA attachment was obtained as 68.3 µmol g^?1. HSA adsorption onto unmodified and Cibacron Blue F3GA‐attached mPHEMA beads was investigated batchwise. The non‐specific adsorption of HSA was very low (1.8 mg g^?1). Cibacron Blue F3GA attachment onto the beads significantly increased the HSA adsorption (94.5 mg g^?1). The maximum HSA adsorption was observed at pH 5.0. Higher HSA adsorption was observed from human plasma (138.3 mg HSA g^?1). Desorption of HSA from Cibacron Blue F3GA‐attached mPHEMA beads was obtained by using 0.1 M Tris/HCl buffer containing 0.5 M NaSCN. High desorption ratios (up to 98% of the adsorbed HSA) were observed. It was possible to re‐use Cibacron Blue F3GA‐attached mPHEMA beads without any significant decreases in their adsorption capacities. Copyright © 2004 Society of Chemical Industry     

Preparation and characterization of micron‐sized non‐porous magnetic polymer microspheres with immobilized metal affinity ligands by modified suspension polymerization

A novel preparation method of micron‐sized non‐porous magnetic polymer microspheres with immobilized metal affinity ligands was developed. A modified suspension polymerization of methacrylate (MA) and divinylbenzene (DVB) was performed in the presence of oleic acid‐coated magnetic Fe₃O₄ nanoparticles to obtain magnetic poly (methacrylate‐divinylbenzene) (mPMA‐DVB) microspheres. Through ammonolysis using ethylenediamine (EDA) and subsequent carboxymethylation with chloroacetic acid, magnetic polymer microspheres with chelate ligands of iminodiacetic acid (IDA) were obtained. Charging with copper ions resulted in magnetic polymer microspheres capable of binding proteins that display metal affinity. The morphology, magnetic properties, and composition of magnetic polymer microspheres were characterized with scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and Fourier transform infrared spectroscopy (FTIR), respectively. Bovine hemoglobin (BHb) was adopted as a model protein to investigate their affinity adsorption capacity. It was found that the adsorption capacity was as high as 168.2 mg/g microspheres and with rather low non‐specific adsorption. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2174–2180, 2005     

DNA adsorption on a poly‐L‐lysine‐immobilized poly(2‐hydroxyethyl methacrylate) membrane

The DNA adsorption properties of poly‐L ‐lysine‐immobilized poly(2‐hydroxyethyl methacrylate) (pHEMA) membrane were investigated. The pHEMA membrane was prepared by UV‐initiated photopolymerization and activated with epichlorohydrin. Poly‐L ‐lysine was then immobilized on the activated pHEMA membrane by covalent bonding, via a direct chemical reaction between the amino group of poly‐L ‐lysine and the epoxy group of pHEMA. The poly‐L ‐lysine content of the membrane was determined as 1537 mg m^?2. The poly‐L ‐lysine‐immobilized membrane was utilized as an adsorbent in DNA adsorption experiments. The maximum adsorption of DNA on the poly‐L ‐lysine‐immobilized pHEMA membrane was observed at 4 °C from phosphate‐buffered salt solution (pH 7.4, 0.1 M; NaCl 0.5 M) containing different amounts of DNA. The non‐specific adsorption of DNA on the plain pHEMA membrane was low (about 263 mg m^?2). Higher DNA adsorption values (up to 5849 mg m^?2) were obtained in which the poly‐L ‐lysine‐immobilized pHEMA membrane was used. Copyright © 2003 Society of Chemical Industry     

Poly(acrylamide‐allyl glycidyl ether) cryogel as a novel stationary phase in dye‐affinity chromatography

Poly(acrylamide‐allyl glycidyl ether) [poly(AAm‐AGE)] cryogel was prepared by bulk polymerization which proceeds in an aqueous solution of monomers frozen inside a glass column (cryo‐polymerization). After thawing, the monolithic cryogel contains a continuous polymeric matrix having interconnected pores of 10–100 μm size. Cibacron Blue F3GA was immobilized by covalent binding onto poly(AAm‐AGE) cryogel via epoxy groups. Poly(AAm‐AGE) cryogel was characterized by swelling studies, FTIR, scanning electron microscopy, and elemental analysis. The equilibrium swelling degree of the poly(AAm‐AGE) monolithic cryogel was 6.84 g H₂O/g cryogel. Poly(AAm‐AGE) cryogel containing 68.9 μmol Cibacron Blue F3GA/g was used in the adsorption/desorption of human serum albumin (HSA) from aqueous solutions and human plasma. The nonspecific adsorption of HSA was very low (0.2 mg/g). The maximum amount of HSA adsorption from aqueous solution in acetate buffer was 27 mg/g at pH 5.0. Higher HSA adsorption value was obtained from human plasma (up to 74.2 mg/g). Desorption of HSA with a purity of 92% from Cibacron Blue F3GA attached poly(AAm‐AGE) cryogel was achieved using 0.1M Tris/HCl buffer containing 0.5M NaCl. It was observed that HSA could be repeatedly adsorbed and desorbed with poly(AAm‐AGE) cryogel without significant loss in the adsorption capacity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Vitamin A microencapsulation within poly(methyl methacrylate)‐g‐polyethylenimine microspheres: Localized proton buffering effect on vitamin A stability

To stabilize vitamin A in a cosmetic/dermatological formulation, we present here a new encapsulation method based on polymer microspheres having a localized “proton‐buffering” capacity. Poly(methyl methacrylate)‐g‐polyethylenimine (PMMA‐g‐PEI) was prepared by direct condensation grafting of PEI onto poly(methyl methacrylate‐co‐methyl acrylic acid). The reaction was confirmed by FT‐IR analysis showing the amide vibration at 1,550 cm^?1. Elemental analysis indicated that the weight content of the grafted PEI was 1.6% (w/w). Vitamin A was encapsulated into PMMA‐g‐PEI microspheres by using an oil‐in‐water (O/W) single emulsion method. The presence of PEI moiety dramatically improved the chemical stability of vitamin A in microspheres. Vitamin A encapsulated within PMMA‐g‐PEI microspheres maintained 91% of its initial activity after 30‐day incubation at 40°C, while only maintaining 60% within plain PMMA microspheres. This study demonstrates that proton‐buffering within hydrophobic polymer matrix is a useful strategy for stabilizing “acid‐labile” active ingredients. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 517–522, 2004