Gözde Baydemir

Selective removal of 17β-estradiol with molecularly imprinted particle-embedded cryogel systems

The selective removal of 17β-estradiol (E2) was investigated by using molecularly E2 imprinted (MIP) particle embedded poly(hydroxyethyl methacrylate) (PHEMA) cryogel. PHEMA/MIP composite cryogel was characterized by FTIR, SEM, swelling studies, and surface area measurements. E2 adsorption studies were performed by using aqueous solutions which contain various amounts of E2. The specificity of PHEMA/MIP cryogel to recognition of E2 was performed by using cholesterol and stigmasterol. PHEMA/MIP cryogel exhibited a high binding capacity (5.32 mg/gpolymer) and high selectivity for E2 in the presence of competitive molecules, cholesterol (k(E2/cholesterol) = 7.6) and stigmasterol (k(E2/Stigmasterol) = 85.8). There is no significant decrease in adsorption capacity after several adsorption-desorption cycles.

Molecularly imprinted composite cryogel for albumin depletion from human serum

A new composite protein‐imprinted macroporous cryogel was prepared for depletion of albumin from human serum prior to use in proteom applications. Polyhydroxyethyl‐methacylate‐based molecularly ımprinted polymer (MIP) composite cryogel was prepared with high gel fraction yields up to 83%, and its morphology and porosity were characterized by Fourier transform ınfrared, scanning electron microscopy, swelling studies, flow dynamics, and surface area measurements. Selective binding experiments were performed in the presence of competitive proteins human transferrin (HTR) and myoglobin (MYB). MIP composite cryogel exhibited a high binding capacity and selectivity for human serum albumin (HSA) in the presence of HTR and MYB. The competitive adsorption amount for HSA in MIP composite cryogel is 722.1 mg/dL in the presence of competitive proteins (HTR and MYB). MIP composite cryogel column was successfully applied in the fast protein liquid chromatography system for selective depletion of albumin in human serum. The depletion ratio was highly increased by embedding beads into cryogel (85%). Finally, MIP composite cryogel can be reused many times with no apparent decrease in HSA adsorption capacity. Copyright

Molecularly imprinted composite cryogels for hemoglobin depletion from human blood

A molecularly imprinted composite cryogel (MICC) was prepared for depletion of hemoglobin from human blood prior to use in proteome applications. Poly(hydroxyethyl methacrylate) based MICC was prepared with high gel fraction yields up to 90%, and characterized by Fourier transform infrared spectrophotometer, scanning electron microscopy, swelling studies, flow dynamics and surface area measurements. MICC exhibited a high binding capacity and selectivity for hemoglobin in the presence of immunoglobulin G, albumin and myoglobin. MICC column was successfully applied in fast protein liquid chromatography system for selective depletion of hemoglobin for human blood. The depletion ratio was highly increased by embedding microspheres into the cryogel (93.2%). Finally, MICC can be reused many times with no apparent decrease in hemoglobin adsorption capacity. Copyright

Heparin removal from human plasma using molecular imprinted cryogels

Abstract In this study, heparin-imprinted poly(hydroxyethyl methacrylate-N-[(3-dimethylamino)-propyl] methacrylamide) cryogel column (HpMIP) was synthesized for removal of Hp from human plasma using molecular imprinting technique. Hp removal studies were performed from both aqueous solution and human plasma. Selectivity studies were performed using fast protein liquid chromatography (FPLC) system. The obtained results showed that the HpMIP column can remove Hp from both aqueous solutions and human plasma samples selectively. Ninety per cent of Hp was removed from 28 U/mL of human plasma samples successfully. Non-imprinted cryogel column (NIP) and plane PHEMA column were also synthesized to compare selectivity and non-specific adsorption properties.

Macroporous PHEMA-based cryogel discs for bilirubin removal

Abstract A novel N-methacryloyl-L-tryptophan methyl ester (MATrp) containing poly (hydroxyethyl methacrylate) cryogel (PHEMATrp) disc was prepared for removal of bilirubin (BR) out of human plasma. PHEMATrp cryogel disc was produced by bulk polymerization, with high gelation yield up to 92% and characterized by swelling tests, scanning electron microscopy (SEM), elemental analysis, Brunauer– Emmett–Teller (BET) analysis, contact angle measurements and surface energy calculations. BR adsorption studies were performed in a batch system, and the maximum BR adsorption capacity was found as 22.2 mg/g cryogel disc.

Synthesis and characterization of amino acid containing Cu(II) chelated nanoparticles for lysozyme adsorption.

Immobilized metal ion affinity chromatography (IMAC) is a useful method for adsorption of proteins that have an affinity for transition metal ions. In this study, poly(hydroxyethyl methacrylate-methacryloyl-L-tryptophan) (PHEMATrp) nanoparticles were prepared by surfactant free emulsion polymerization. Then, Cu(II) ions were chelated on the PHEMATrp nanoparticles to be used in lysozyme adsorption studies in batch system. The maximum lysozyme adsorption capacity of the PHEMATrp nanoparticles was found to be 326.9 mg/g polymer at pH 7.0. The nonspecific lysozyme adsorption onto the PHEMA nanoparticles was negligible. In terms of protein desorption, it was observed that adsorbed lysozyme was readily desorbed in medium containing 1.0 M NaCl. The results showed that the metal-chelated PHEMATrp nanoparticles can be considered as a good adsorbent for lysozyme purification.

Affinity composite cryogel discs functionalized with Reactive Red 120 and Green HE 4BD dye ligands: application on the separation of human immunoglobulin G subclasses.

Naturally produced by the human immune system, immunoglobulin nowadays is widely used for in vivo and in vitro purposes. The increased needs for pure immunoglobulin have prompted researchers to find new immunoglobulin chromatographic separation processes. Cryogels as chromatographic adsorbents, congregate several mechanical features including good compatibility, large pore structure, flexibility, short diffusion pathway and stability. These different characteristics make them a good alternative to conventional chromatographic methods and allowing their potential use in separation technology. In the present study, two sets of poly(2-hydroxyethyl methacrylate) (PHEMA) based beads were prepared and functionalized with Reactive Red 120 (RR) and Reactive Green HE 4BD (RG) dyes, and then embedded into supermacroporous cryogels. The morphology, physical and chemical features of the prepared bead embedded composite cryogel discs (CCDs) were performed by scanning electron microscopy (SEM), swelling test, elemental analysis and Fourier transform infrared spectroscopy (FTIR). The results showed that the embedded composite cryogel discs have a specific surface area of 192.0 m(2)/g with maximum adsorption capacity of HIgG 239.8 mg/g for the RR functionalized CCD and 170 mg/g for RG functionalized CCD columns, both at pH 6.2.

Cholesterol removal from various samples by cholesterol-imprinted monosize microsphere-embedded cryogels

Abstract Cholesterol-imprinted monosize poly(glycidyl methacrylate-N-methacryloyl-(L)-tyrosine methylester) microspheres were embedded into the poly(hydroxyethyl methacrylate) (PHEMA) cryogels and the resulting composite cryogel was used for the selective removal of cholesterol. Composite cryogels were characterized by swelling tests, multipoint BET apparatus, SEM, FTIR and elemental analysis studies. Specific surface area of the PHEMA cryogel was increased from 13 to 72.7 m2/g by embedding of microspheres. Composite cryogels removed 80% of cholesterol from homogenized milk. The maximum adsorption capacity was found as 42.7 mg/g for intestinal mimicking solution. After 20 adsorption–desorption cycles, there was no remarkable decrease in the adsorption capacity.

Microsphere-embedded cryogel for selective and efficient depletion of immunoglobulin G from human serum

Abstract In this study a novel composite cryogel column was synthesized for affinity depletion of immunoglobulin G (IgG) from human serum. The microsphere-embedding technique combines the large surface area of microspheres with excellent properties of cryogels. The poly(hydroxyethyl methacrylate- N-methacryloyl-L-histidine methyl ester) microsphere (2 μm size)- embedded composite cryogel (MECC) column was synthesized and characterized by various methods. The specific surface area of the composite cryogel was found as 92 m2/g by using BET measurement. Maximum HIgG adsorption on MECC column was found as 50.5 mg/g. MECC column can be reused many times with no apparent decrease in HIgG adsorption capacity.

Composite cryogels for lysozyme purification

Beads‐embedded novel composite cryogel was synthesized to purify lysozyme (Lyz) from chicken egg white. The poly(hydroxyethyl methacrylate‐N‐methacryloyl‐L‐phenylalanine) (PHEMAPA) beads of smaller than 5 µm size were synthesized by suspension polymerization and then embedded into a poly(hydroxyethyl methacrylate) (PHEMA)‐based cryogel column. The PHEMAPA bead‐embedded cryogel (BEC) column was characterized by swelling tests, scanning electron microscopy (SEM), surface area measurements by the Brunauer–Emmett–Teller (BET) method, elemental analysis, and flow dynamics. The specific surface area of the PHEMAPA BEC was found as 41.2 m2/g using BET measurements. Lyz‐binding experiments were performed using aqueous solutions in different conditions such as initial Lyz concentration, pH, flow rate, temperature, and NaCl concentration of an aqueous medium. The PHEMAPA BEC column could be used after 10 adsorption–desorption studies without any significant loss in adsorption capacity of Lyz. The PHEMAPA BEC column was used to purify Lyz from chicken egg white, and gel electrophoresis was used to estimate the purity of Lyz. The chromatographic application of the PHEMAPA BEC column was also performed using fast protein liquid chromatography.