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Öğe Bovine Serum Albumin Adsorption by Dye Derived Poly(hydroxyethyl methacrylate) [PHEMA] Membranes(2015) Çimen, Duygu; Yılmaz, FatmaProcion Brown MX 5BR (PBR) attached poly(hydroxyethyl methacrylate) [PHEMA] membranes were used for adsorption of albumin. The poly(hydroxyethyl methacrylate) was selected as the basic component due to it’s inertness, mechanical strength, chemical and biological stability, and biocompatibility. Different amounts of PBR was covalently attached to the poly(hydroxyethyl methacrylate) membrane to prepare poly(hydroxyethyl methacrylate)-Procion Brown [PHEMA-PBR] membrane. PHEMA-PBR membrane was characterized with Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Dye attached PHEMA membranes were used in bovine serum albumin (BSA) adsorption studies to assess the effects of pH, protein concentration, flow rate, temperature and ionic strength. The maximum albumin adsorption of PBR attached PHEMA membrane was 14.79 mg/g at pH 7.0 from aqueous solutions. Desorption of albumin was studied with 1.0 M NaCI solution in a continuous system. The reusability of the adsorption medium was tested for 4 adsorption-desorption cycles. Adsorption isotherms fitted Freundlich adsorption model and adsorption kinetics followed pseudo-second order model.Öğe Cellulose-based nanobiosorbents: An insight(Elsevier, 2022) Göktürk, Ilgim; Çimen, Duygu; Özbek, Merve Asena; Yilmaz, Fatma; Denizli, AdilThe increasing world population and ever-growing industrialization cause more toxic heavy metals and organic pollutants to mix into natural resources than ever before. Simple and cost-effective methods based on adsorption applicable in many parts of the world are widely used to remove various pollutants from different sources. Cellulose, a natural polysaccharide, has excellent mechanical properties, high surface area, and it can be modified with specific functional groups, such as carboxyl, amino, sulfo groups, and cyclodextrin. Recently, nanocellulose and its applications have attracted high interest in both research and industrial areas due to their sustainability, availability, environmentally friendly, and remarkable applications in various fields. This chapter describes the recent advances in the production and application of cellulose-based nanomaterials used as bioadsorbents. Cellulose nanomaterials including cellulose nanocrystals and cellulose nanofibrils are produced using different preparation processes resulting in materials with unique structures and physicochemical properties and are examined in various fields such as biomedical, sensors, wastewater treatment, paper and board/packaging industry. In this chapter, the information about nanocellulose and its types and the recent developments of the cellulose-based nanobioadsorbents's environmental applications are comprehensively discussed. We emphasize the current trends and future remarks based on the environmental applications of cellulose-based nanomaterials. © 2022 Elsevier Inc. All rights reserved.Öğe Development of surface plasmon resonance sensors based on molecularly imprinted nanofilms for sensitive and selective detection of pesticides(Elsevier Science Sa, 2017) Saylan, Yeşeren; Akgönüllü, Semra; Çimen, Duygu; Derazshamshir, Ali; Bereli, Nilay; Yılmaz, FatmaPesticides have been utilized in agriculture for decades. However, their widespread use has increased multiple concerns due to their known and suspected toxicities on long-term human health risks in scientific and industrial communities. Thus, detecting pesticides will have a great impact on their management, as well as improve their toxicity effects over humans. Here, we fabricate molecularly imprinted nanofilms and integrate them with surface plasmon resonance (SPR) sensors for sensitive, selective, fast and real-time detection of multiple pesticides, including cyanazine (SNZ), simazine (SMZ) and atrazine (ATZ). The molecularly imprinted nanofilms onto the SPR gold surfaces are prepared via UV polymerization reactions, which consist of N-methacryloyl-L-phenylalanine methyl ester (MAPA) as a functional monomer, 1-vinylimidazole (VIM) as a co-monomer, and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. The real-time measurements on SPR sensor provide a detection range from 0.10 to 6.64 nM, as well as denote a limit of detection (LOD) values of 0.095, 0.031 and 0.091 nM for SNZ, SMZ and ATZ, respectively. Furthermore, we perform selectivity test, where SNZ, SMZ and ATZ are examined as competitor agents. Overall, the pesticide imprinted SPR sensors have been found to be highly selective and sensitive. These SPR sensors also hold great potential to be used an alternative method for the existing pesticide monitoring approaches due to their reusability, fast response, and easy-to-use properties, as well as can be tailored to detect and real-time monitor of other pesticides. (C) 2016 Elsevier B.V. All rights reserved.Öğe Dye affinity cryogels for plasmid DNA purification(Elsevier, 2015) Çimen, Duygu; Yılmaz, Fatma; Perçin, Işık; Türkmen, Deniz; Denizli, AdilThe aim of this study is to prepare megaporous dye-affinity cryogel discs for the purification of plasmid DNA (pDNA) from bacterial lysate. Poly(hydroxyethyl methacrylate) [PHEMA] cryogel discs were produced by free radical polymerization initiated by N,N,N',N'-tetramethylene diamine (TEMED) and ammonium persulfate (APS) redox pair in an ice bath. Cibacron Blue F3GA was used as an affinity ligand (loading amount: 68.9 mu mol/g polymer). The amount of pDNA adsorbed onto the PHEMA-Cibacron Blue F3GA cryogel discs first increased and then reached a plateau value (i.e., 32.5 mg/g cryogel) at 3.0 mg/mL pDNA concentration. Compared with the PHEMA cryogel (0.11 mg/g cryogel), the pDNA adsorption capacity of the PHEMA-Cibacron Blue F3GA cryogel (32.4 mg/g polymer) was improved significantly due to the Cibacron Blue 3GA immobilization onto the polymeric matrix. pDNA adsorption amount decreased from 11.7 mg/g to 1.1 mg/g with the increasing of NaCl concentration. The maximum pDNA adsorption was achieved at 4 degrees C The overall recovery of pDNA was calculated as 90%. The PHEMA-Cibacron Blue F3GA cryogel discs could be used five times without decreasing the pDNA adsorption capacity significantly. The results show that the PHEMA-Cibacron Blue F3GA cryogel discs promise high selectivity for pDNA. (C) 2015 Elsevier B.V. All rights reserved.Öğe Enantioseparation of aromatic amino acids using CEC monolith with novel chiral selector, N-methacryloyl-L-histidine methyl ester(Wiley, 2013) Aydoğan, Cemil; Yılmaz, Fatma; Çimen, Duygu; Uzun, Lokman; Denizli, AdilA new type of polymethacrylate-based monolithic column with chiral stationary phase was prepared for the enantioseparation of aromatic amino acids, namely d,l-phenylalanine, d,l-tyrosine, and d,l-tryptophan by CEC. The monolithic column was prepared by in situ polymerization of butyl methacrylate (BMA), N-methacryloyl-l-histidine methyl ester (MAH), and ethylene dimethacrylate (EDMA) in the presence of porogens. The porogen mixture included DMF and phosphate buffer. MAH was used as a chiral selector. FTIR spectrum of the polymethacrylate-based monolith showed that MAH was incorporated into the polymeric structure via in situ polymerization. Some experimental parameters including pH, concentration of the mobile phase, and MAH concentration with regard to the chiral CEC separation were investigated. Single enantiomers and enantiomer mixtures of the amino acids were separately injected into the monolithic column. It was observed that l-enantiomers of aromatic amino acids migrated before d-enantiomers. The reversal enantiomer migration order for tryptophan was observed upon changing of pH. Using the chiral monolithic column (100 m id and 375 m od), the best chiral separation was performed in 35:65% ACN/phosphate buffer (pH 8.0, 10mM) with an applied voltage of 12 kV in CEC. SEM images showed that the chiral monolithic column has a continuous polymeric skeleton and large through-pore structure.Öğe Nanodevices and nanomachines at the nanoscale biophysics(Elsevier, 2023) Akgönüllü, Semra; Çimen, Duygu; Göktürk, Ilgım; Yılmaz, Gaye Ezgi; Yılmaz, Fatma; Denizli, AdilA lot of today’s nanoscale technologies have been developed to achieve a deeper insight into how material acts on a small scale. As nanostructured materials have a high surface area concerning their volume, phenomena such as friction and sticking are more important than they are in bigger materials. Engineering at very tiny scales of length will finally create technologies that employ materials with novel and fundamentally unique characteristics. The nanoscale devices will take challenges for future technologies. This will contain nanomedicine fields, including plasmonics, optical molecular switches, nanooptical and subdiffraction-limited imaging, as well as anticancer therapies and diagnostics. To create nanodevices, there are two basic approaches: a top-down approach and a bottom-up approach. In recent years, the application of nanotechnology as a novel procedure for diagnosis, monitoring, and care of diseases has increased interest in the biomedical area. In this chapter, we focus on highlighting the recent development and applications of nanodevices and nanomachines in medical biophysics. © 2024 Elsevier Inc. All rights reserved.Öğe SPR signal enhancement with silver nanoparticle-assisted plasmonic sensor for selective adenosine detection(IEEE-Inst Electrical Electronics Engineers Inc, 2022) Göktürk, Ilgım; Yücel, Monireh Bakhshpour; Çimen, Duygu; Yılmaz, Fatma; Bereli, Nilay; Denizli, AdilIn this study, we fabricated adenosine imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-L-cysteine methyl ester-silver nanoparticles (AgNPs)-N-methacryloyl-L-phenylalanine methyl ester) (MIP-Ag) sensor. It is a sensitive, simple, low-cost, and label-free adenosine determination in an aqueous solution without the need for any complicated coupling processes. The sensor without the addition of AgNPs (MIP) was prepared for control experiments to examine the effect of incorporated AgNPs to increase the signal response of surface plasmon resonance. Also, non-imprinted (NIP-Ag) sensor were designed using the same polymerization recipe without adding adenosine to evaluate the imprinting efficiency. The characterization studies of MIP-Ag, NIP-Ag and MIP sensors were carried out by atomic force microscopy and contact angle measurements. It was determined that the MIP-Ag sensor detected the target adenosine molecule 5.10 times more selectively than the competitor guanosine and 3.92 times more than thymidine. Imprinting efficiency was determined by comparing the signal response of MIP-Ag and NIP-Ag sensors. Repeatability studies of the MIP-Ag sensor were statistically analyzed for the 1.0 ppm adenosine, and the percent relative standard deviation of the intraday assays of less than 1.0% showed an insignificant decrease in the detection of adenosine after four adsorption-desorption cycles.Öğe Study on an Hydrophilic Interaction Electrochromatography Method for Separation of Sulfonamide Antibiotics(2014) Aydoğan, Cemil; Yılmaz, Fatma; Çimen, Duygu; Andaç, Müge; Shaikh, Huma; Denizli, AdilThis study describes the preparation of a hydrophilic monolithic column and its application to sulfonamide antibiotics. The column was prepared by single step in situ polymerization of 2-hydroxyethyl methacrylate (HEMA), ethylene dimethacrylate (EDMA) and methacrylic acid (MAA) in a binary porogenic solvent consisting of toluene and 1-dodecanol, inside a 100 µm-i.d. capillary. The resulting monolith was electrochromatographically characterized as well as SEM. The prepared column showed hydrophilic behaviour using thiourea and toluene as markers. The SEM images showed that the monolithic column composed of spherical particles of approximately 2 µm in diameter. Using this hydrophilic monolith as stationary phase, hydrophilic interaction electrochromatography of sulfonamide antibiotics as a new method was developed. The method was successfully used for the separation of sulfonamide antibiotics. Some parameters including acetonitrile (ACN) content, pH and ionic strength on the separation of the sulfonamides, namely sulfaprydine, sulfadiazine, sulfamethazine, sulfisoxazole and sulfadoxine were also investigated. A typical hydrophilic interaction separation mechanism was revealed at higher organic solvent content (ACN > 60%).Öğe Surface plasmon resonance based nanosensors for detection of triazinic pesticides in agricultural foods(Elsevier, 2017) Yılmaz, Fatma; Saylan, Yeşeren; Akgönüllü, Semra; Çimen, Duygu; Derazshamshir, Ali; Bereli, Nilay; Denizli, AdilHerein, we have focused on the preparation of triazinic pesticide imprinted SPR nanosensors for detection of herbicides. Triazinic pesticides are weedkillers that are related with possible carcinogenic effects, birth defects, and menstrual problems when uptake by humans. Although there are restrictions and bans on their use in some countries they are still one of the most widely used pesticides in the world. The development of rapid, sensitive, and inexpensive diagnosis tools for environmental and biological monitoring is currently a research area of great interest. Surface plasmon resonance (SPR) nanosensors have been used widely for the detection of triazinic pesticides because of their simplicity, lack of requirement for labeling and ease of miniaturization, low cost, high specificity and sensitivity, and real-time measurement. Molecularly imprinted polymers that have molecular recognition talent, are easy to prepare, less expensive, stable, and can be manufactured with good reproducibility, are used for the creation of biorecognitive surfaces on the SPR nanosensors. Herein, we have focused on the production of triazinic pesticide-imprinted SPR nanosensors. © 2017 Elsevier Inc. All rights reserved.
