Kimya Mühendisliği

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http://hdl.handle.net/11527/18124

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  • Öge
    Fabrication of MIL-101(Fe)-embedded biopolymeric films and their biomedical applications
    (Springer, 2024) Kocaağa, Banu ; Bağımsız, Gamze ; Alev, İbrahim Avni ; Miavaghi, Mehran Aliari ; Sirkecioğlu, Ahmet ; Batirel, Saime ; Güner, Fatma Seniha ; Kimya Mühendisliği
    The development of wound-dressing materials with superior therapeutic effects, controlled bioactive agent release, and optimal mechanical properties is crucial in healthcare. This study introduces innovative hydrogel films designed for the sustained release of the local anesthetic drug Procaine (PC), triggered by pH changes. These films are composed of MIL-101(Fe) particles and pectin polymers. MIL-101(Fe) was chosen for its high surface area, stability in aqueous environments, and biocompatibility, ensuring low toxicity to normal cells. MIL-101(Fe)-embedded-pectin hydrogels were synthesized and characterized using Fourier-transformed infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma (ICP) spectrometry, particle size analysis, and goniometry. Rheological analysis assessed the hydrogels’ viscoelastic behavior, and UV-spectrophotometry was utilized for drug loading and release studies. The hydrogels exhibited shear-thinning properties, enhancing shape adaptability and recovery, crucial for wound-dressing applications. Controlled drug release was achieved by maintaining the PC solution’s pH between 8.2 and 9.8 during the drug-loading step. The hydrogel film’s impact on wound healing was evaluated through an in vitro wound healing assay, and cytotoxicity was assessed using a WST-1 cell proliferation assay with human dermal fibroblast cells. Results demonstrated that pectin composites enhance cell viability and support fibroblast cell migration without adverse effects, indicating their potential for effective wound healing applications. This study highlights the potential of MIL-101(Fe)-embedded-pectin hydrogels in advancing wound care technology.
  • Öge
    Identifying and assessing putative allosteric sites and modulators for CXCR4 predicted through network modeling and site identification by Ligand Competitive Saturation
    (American Chemical Society, 2024) İnan, Tuğçe ; Flinko, Robin ; Lewis, George K. ; MacKerell, Alexander D., Jr. ; Kürkçüoğlu, Özge ; 0000-0001-8287-6804 ; 0000-0003-0228-3211 ; Kimya Mühendisliği
    The chemokine receptor CXCR4 is a critical target for the treatment of several cancer types and HIV-1 infections. While orthosteric and allosteric modulators have been developed targeting its extracellular or transmembrane regions, the intramembrane region of CXCR4 may also include allosteric binding sites suitable for the development of allosteric drugs. To investigate this, we apply the Gaussian Network Model (GNM) to the monomeric and dimeric forms of CXCR4 to identify residues essential for its local and global motions located in the hinge regions of the protein. Residue interaction network (RIN) analysis suggests hub residues that participate in allosteric communication throughout the receptor. Mutual residues from the network models reside in regions with a high capacity to alter receptor dynamics upon ligand binding. We then investigate the druggability of these potential allosteric regions using the site identification by ligand competitive saturation (SILCS) approach, revealing two putative allosteric sites on the monomer and three on the homodimer. Two screening campaigns with Glide and SILCS-Monte Carlo docking using FDA-approved drugs suggest 20 putative hit compounds including antifungal drugs, anticancer agents, HIV protease inhibitors, and antimalarial drugs. In vitro assays considering mAB 12G5 and CXCL12 demonstrate both positive and negative allosteric activities of these compounds, supporting our computational approach. However, in vivo functional assays based on the recruitment of β-arrestin to CXCR4 do not show significant agonism and antagonism at a single compound concentration. The present computational pipeline brings a new perspective to computer-aided drug design by combining conformational dynamics based on network analysis and cosolvent analysis based on the SILCS technology to identify putative allosteric binding sites using CXCR4 as a showcase.
  • Öge
    İTÜ Kimya Mühendisliği 1. Lisansüstü Sempozyumu Özet Kitabı 26 Nisan 2019, İstanbul
    (İTÜ, 2019-04-26) Kimya Mühendisliği ; Gümüşlü Gür, Gamze ; Genceli Güner, Fatma Elif
  • Öge
    Non-covalent functionalization of magnetic carbon nanotubes with Fmoc amino acid-modified polyethylene glycol
    (Wiley, 2024) Murat, Fusun Sevval ; Güner Yılmaz, Özde Zeynep ; Bozoglu, Serdar ; Batirel, Saime ; Baysak-Käseberg, Elif ; Hizal, Gurkan ; Karatepe, Nilgün ; Güner, Fatma Seniha ; orcid.org/0000-0002-3414-4868 ; Kimya Mühendisliği
    Once dispersion and cytotoxicity issues are resolved, it has been proven that carbon nanotubes (CNTs) have great advantages in biomedical applications due to their unique properties. In this study, the superiority of carbon nanotubes was combined with magnetic targeting strategies, and a solution to the distribution problem in the aqueous media of the resulting CNTs decorated with iron oxide (mCNTs) was sought. A non-covalent functionalization approach has been utilized to overcome this fundamental drawback of mCNTs. Conjugates of polyethylene glycol monomethyl ether and 9- fluorenyl methyl chloroformate (Fmoc) amino acids were used to coat the lateral surfaces of mCNTs, making them more water-soluble. The selected Fmoc amino acids have different numbers of aromatic rings, which is known to affect the coating efficiency in non-covalent functionalization and therefore, the dispersion behavior of the CNTs. Their coating yields, dispersion behaviors, magnetism, charge, and size properties have been determined. All coated mCNT samples displayed superparamagnetic behavior. Dispersion tests showed a promise to increase the stability of mCNTs with this approach. Moreover, we demonstrated that the functionalization of mCNTs affects cell viability in a dose-dependent manner. The main finding of this study is that mCNTs can be successfully functionalized with Fmoc amino acid-modified polyethylene glycol.
  • Öge
    Olive stone powder filled bio-based polyamide 5.6 biocomposites : biodegradation in natural soil and mechanical properties
    (Springer, 2024) Gülel, Şebnem ; Güvenilir, Yüksel ; 0000-0002-2527-5233 ; 0000-0002-1684-9055 ; Kimya Mühendisliği
    The extensive use of non-biodegradable and petroleum derived polymers in industry exacerbates environmental problems associated with plastic waste accumulation and fossil resource depletion. The most promising solution to overcome this issue is the replacement of these polymers with biodegradable and bio-based polymers. In this paper, novel biocomposites were prepared from bio-based polyamide 5.6 (PA56) with the addition of olive stone powder (OSP) at varying weight concentrations by melt compounding method. The degradability of the prepared biocomposites is investigated through soil burial test, and assessed by reduction in their mechanical properties. The biodegradability of bio-based polyamide 5.6 is shown to be improved by addition of olive stone powder, and its effects on the properties of polymer matrix are elucidated. The Fourier transform infrared (FTIR) spectrum of the biocomposites indicate the successful incorporation of OSP into PA56 polymer matrix. After six-month soil burial test, scanning electron microscopy and FTIR show the degradation of PA56 through morphological and structural changes, respectively. Differential scanning calorimetry reveals the changes in the transition temperatures of the polymer matrix and an increase in crystallinity. Thermogravimetric analysis is used on the biocomposite to determine the fraction of its components, polymer and biofiller, and the results show that 2.67% (w/w) of the polyamide 5.6 is biodegraded at the end of the six-month soil burial.
  • Öge
    Plasma treated-double layer electrospun fiber mats from thermoplastic polyurethane and gelatin for wound healing applications
    (Wiley, 2024) Yıldırım, Arzu ; Erdoğan, Eray Sarper ; Çağlayan, Şeyma ; Keskinkaya, Rüya ; Türker, Yurdanur ; Karbancıoğlu-Güler, Funda ; Dikmetaş, Dilara Nur ; Batirel, Saime ; Erol Taygun, Melek ; Guner, F. Seniha ; orcid.org/0000-0002-3414-4868 ; Kimya Mühendisliği
    Conventional wound treatment options provide a barrier against exogenous microbial penetration but cannot simultaneously provide an antibacterial characteristic and promote healing. However, bioactive dressings can accelerate wound healing and have an antibacterial effect in addition to being able to cover and protect lesions. In this study, double-layer thermoplastic polyurethane (TPU)-gelatin fibrous dressings that mimic the epidermis and dermis layers of the skin were fabricated via electrospinning technique. As a bioactive agent, Hypericum perforatum oil (HPO) was utilized to impart antibacterial and therapeutic properties to the dressings. Tannic acid was also used in fiber mat formulations as a cross-linking agent. Oxygen plasma treatment was applied as a surface activation technique to improve adhesion of TPU and gelation layers. The fiber structure of the mats was revealed by a scanning electron microscopy (SEM) study. Fourier transform infrared (FTIR) spectroscopy was used to demonstrate HPO loading onto the mats. The water vapor transmission rate (WVTR) and fluid absorbency of the mats were compared with some commercial dressings. According to these results, it can be suggested that the mats can be used for moderate to high exudative wounds. All dressings, even the control sample showed antibacterial features against both Staphylococcus aureus and Escherichia coli bacteria due to the tannic acid. In vitro wound healing assays were carried out on the plasma-treated sample and it was observed that the sample did not negatively affect the migration and proliferation abilities of the cells which are necessary for wound healing. Overall results indicated that the plasma-treated fibrous mat would be a good candidate as a wound dressing material having an antibacterial character.
  • Öge
    Removal of boron from wastewaters using valonia-tannin-based biosorbent produced via spray drying
    (Sage Publications, 2024) Erdol-Aydin, Nalan ; Sezer, Serhat ; Esin, Berk ; Nasun-Saygili, Gülhayat ; https://orcid.org/0000-0002-3675-2744 ; Kimya Mühendisliği
    The primary objective of this study is to assess the adsorption behavior of boron using a tannin-based biosorbent known as tannic acid resin, synthesized from Turkish acorns (valonia) through the spray-drying method. The resulting biosorbent, named Valex, underwent modification into a tannic acid resin-based structure, rendering it suitable for use as a biosorbent. Comprehensive characterization studies involving Fourier transform infrared, X-ray diffraction, scanning electron microscopy, and Brunauer-Emmett-Teller analysis were conducted on this biosorbent. The outcomes demonstrated the effectiveness of tannic acid resin, a tannin-based biosorbent, in removing boron from aqueous solutions. Various parameters such as pH, initial boron concentration, and adsorbent dosage were investigated for their impact on boron removal. The study also delved into adsorption kinetics, adsorption isotherm models, and adsorption thermodynamics. Maximum boron removal, reaching 92.9%, was achieved using 1 g of tannic acid resin-based biosorbent with an initial boron concentration of 8 mg L−1 within 6 h at pH 3. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin isotherm models were applied to experimental data, with the Temkin model demonstrating a good fit. Adsorption kinetics were explored using pseudo-first-order, pseudo-second-order, Elovich, first-order, second-order, and intraparticle diffusion models, with the pseudo-second-order kinetic model fitting the data effectively. The negative values of ΔG° at all temperatures indicated the spontaneous nature of boron adsorption on the tannin resin, and the positive value of ΔH° suggested the endothermic nature of adsorption. This study shows the efficacy of Valex in boron adsorption and suggests its potential application as an effective method for boron removal. This study's findings on the impact of various parameters on boron removal provide insights for optimizing the boron adsorption process in practical applications.
  • Öge
    Tailoring hydrophobicity vs. water capacity of adsorbents for adsorption applications : role of composites
    (Springer, 2024) Atalay-Oral, Çiğdem ; Tatlıer, Melkon ; 0000-0002-8773-2348 ; 0000-0003-2792-410X ; Kimya Mühendisliği
    Water adsorption capacities of various adsorbents reported in the literature were investigated to define a hydrophobicity index that was plotted vs. water capacity. In this plot, logarithmic curves were proposed to be used as indicators of performance limits of adsorbents, especially for adsorption heat pumps. In spite of their useful adsorption properties, zeolites generally exhibited quite low hydrophobicity, remaining well below the logarithmic curve. In this study, the use of composites of zeolite NaY was examined both theoretically and experimentally for improvements in the water capacity and hydrophobicity. Salt impregnation and hydrothermal synthesis experiments were performed to prepare composites of zeolite NaY with LiCl/MgCl2 salts and activated carbon, respectively. Water capacity and hydrophobicity of zeolite NaY composites were generally superior to those of pure zeolite. Zeolite composites may be advantageous for enhancing adsorption capacity and hydrophobicity of zeolites while eliminating low stability and slow adsorption kinetics of other adsorbents. Interface between two different phases might indicate another opportunity to provide improved adsorption properties for zeolite composites.
  • Öge
    Utilizing the potential of waste hemp reinforcement: investigating mechanical and thermal properties of polypropylene and polylactic acid biocomposites
    (American Chemical Society, 2024) Yılmaz, Anıl ; Özkan, Hakan ; Genceli Güner, F. Elif ; 0000-0002-6291-7792 ; 0000-0001-6201-6719 ; Kimya Mühendisliği
    Hemp has gained significant popularity for its diverse applications; however, this study explores the untapped potential of waste hemp (wH) as a cost-effective and sustainable bioadditive for the development of high-performance biocomposites. wH offers advantages such as low cost, easy availability, and suitability for extrusion. Polypropylene (PP) and poly(lactic acid) (PLA) served as polymer matrices for this investigation. In order to enhance the interaction between the wH and polymer matrices, alkaline and silane pretreatments were applied to the wHs of both matrices. At the same time, the MA-g-PP additive was used exclusively for the PP matrix. The resulting PP biocomposite demonstrated Young’s modulus (2986 MPa) and flexural modulus (2490 MPa), surpassing those of neat PP by 109 and 77%, respectively. Similarly, wH40-PLA-A showed enhancements in the PLA biocomposite, with Young’s modulus (6214 MPa) and flexural modulus (5970 MPa) representing an increase of 81 and 56% over that of neat PLA, respectively. The thermal properties and behaviors of the resulting biocomposites were minimally affected by the inclusion of wH as a bioadditive. This study contributes to the advancement of sustainable materials and provides valuable insights into the utilization of wH as a valuable resource for the development of high-performance biocomposites.