Bahar Ergün

Periodic Mesoporous Organosilica-Based Nanocomposite Hydrogels as Three-Dimensional Scaffolds**

a class offunctional organic–inorganic hybrid silica particles on thenanometer-scale, are a new alternative material as porousmaterials for new NC hydrogel formation owing to its uniqueproperties,forexample,highorderedmesopores,highspecificsurface area, narrow pore-size distributions, and easy surfacefunctionalization.

Self-assembled Monolayers and Nanocomposite Hydrogels of Functional Nanomaterials for Tissue Engineering Applications

In biotechnology, SAMs and NC hydrogels of functional nanomaterials are of high interest as 2D and 3D cell culture systems, respectively, to mimic natural ECM and to control cell behaviors. Advanced biotechnological approaches often use nanoscale topography together with suitable surface functionalization, as a model of ECM, to control cell behaviors and tissue formation. SAMs of NMs are effective ECM models as 2D surfaces due to their larger nanostructured surface areas which provide higher molecular density by functionalization on a planar substrate than molecular SAMs. Additionally, NC hydrogels, produced by cross-linking of organic polymers with NMs, are excellent candidates as 3D cell culture systems owing to their optical, cell-compatibility and the extraordinary mechanical 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.

Purification of urease from jack bean (Canavalia ensiformis) with copper (II) chelated poly(hydroxyethyl methacrylate-N-methacryloyl-(l)-histidine methyl ester) cryogels†

Jack bean (Canavalia ensiformis) is the source of interesting proteins that contribute to modern biochemistry, and urease is the primary of these proteins. Owing to its role and occurrence in nature, urease has become a part of extensive studies. In this study, jack bean urease (JBU) was purified by immobilized metal affinity chromatography using Cu2+ chelated poly(hydroxyethyl methacrylate‐N‐methacryloyl‐(l)‐histidine methyl ester) [PHEMAH‐Cu2+]–based cryogels. PHEMAH‐Cu2+ cryogel was synthesized and characterized for swelling degree, morphology (by SEM), N‐methacryloyl‐(l)‐histidine methyl ester and Cu2+ incorporation (by elemental analysis and atomic absorption spectrophotometry). The binding of JBU to PHEMAH‐Cu2+ cryogel was optimized by examining the effect of pH, flow rate and JBU concentration on binding. The maximal binding of JBU was 23.2 mg/dry gram of adsorbent. The maximal binding of JBU extracted from jack bean meal was 67.8 mg/dry gram of adsorbent. The elution of JBU from cryogel column was accomplished by 1.0 M NaCl in 20 mM phosphate buffer (pH 8.0). Molecular weight and purity of JBU from jack bean meal was estimated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis. It was observed that JBU could be repeatedly bound and eluted from (PHEMAH)‐Cu2+ cryogel with less than 10% loss in column capacity. Copyright

Spatially Controlled Channel Entrances Functionalization of Zeolites L

The spatially controlled channel entrances functionalization of disk shaped zeolite L crystals is described. Fluorescent dye or bioactive molecules are immobilized at one end of the channels of zeolite crystals and subsequently the other side of the crystals is derivatized with magnetic iron oxide nanoparticles. The asymmetrically functionalized crystals were used for the control of the movement of bacteria in solution.

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.

Metal-immobilized magnetic nanoparticles for cytochrome C purification from rat liver.

Cu2+‐immobilized magnetic poly(hydroxyethylmethacrylate‐N‐methacryloyl‐(l)‐histidinemethylester) (mPHEMAH) nanoparticles were prepared by surfactant‐free emulsion polymerization for cytochrome C (cyt C) purification from rat liver. Elemental analysis, atomic force microscopy, zeta sizer, and vibrating sample magnetometer were used to characterize mPHEMAH nanoparticles. In addition to these characterization steps, surface area, average particle size, and size distribution of mPHEMAH nanoparticles were determined. Quantity of immobilized Cu2+ was measured using atomic absorption spectrophotometry. N‐Methacryloyl‐(l)‐histidinemethylester and Cu2+ content of mPHEMAH nanoparticles were 0.18 mmol/g polymer and 0.11 mmol/g polymer, respectively. Specific surface area of Cu2+‐immobilized mPHEMAH nanoparticles was 1180 m2/g. Effect of initial cyt C concentration, pH, temperature, and ionic strength on cyt C adsorption onto Cu2+‐immobilized mPHEMAH nanoparticles was investigated. Maximum cyt C adsorption capacity of Cu2+‐immobilized mPHEMAH nanoparticles was 311.9 mg/g polymer. Maximum adsorption was obtained at pH 8.0 and 4 °C. Cu2+‐immobilized mPHEMAH nanoparticles were used ten times with 4.1% decrease in adsorption capacity. In the last stage, Cu2+‐immobilized mPHEMAH nanoparticles were used to purify cyt C from rat liver tissue, and the purity of desorbed fractions was controlled by SDS‐PAGE.

Surface-Mediated Stimuli Responsive Delivery of Organic Molecules from Porous Carriers to Adhered Cells

The alternating layer-by-layer deposition of oppositely charged polyelectrolytes on fluorescence-dye-(Hst)-loaded zeolites L ((Hst) Zeo-PSS/PLL) is described. The arrays and nanocomposite (NC) hydrogels of (Hst) Zeo-PSS/PLL are prepared. The subsequent cell experiments show the potential application of arrays and NC hydrogels of (Hst) Zeo-PSS/PLL as alternative 2D- and 3D-surfaces, respectively, for 2D- and 3D-surface-mediated controlled organic molecules delivery applications.