39 results on '"Topuz F"'
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2. Characterization, Optimization, Physicochemical Properties, and Bioactive Components of Drum-Dried Apple Puree.
- Author
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Topuz, F. Coskun and Pazir, F.
- Subjects
- *
MALTODEXTRIN , *APPLES , *RAW materials , *CHEMICAL properties , *APPLE quality - Abstract
The aim of this study was to detect the effect of drum-drying parameters on certain physical and chemical properties of apple puree powder. Optimum drying conditions were determined using the Response Surface Methodology (RSM). The qualities of apple puree powder products were investigated in terms of water activity, pH, color, phenolics, antioxidant activity and sensory properties. Apple puree (13 Bx°) and maltodextrin (10 DE) were used as the raw material and carrier agent, respectively. Steam pressure, rotational speed and the puree/maltodextrin ratio were chosen as variable parameters. The effects of three of the parameters mentioned were found to be statistically significant: water activity, pH, and the a* and b* parameters of the powders (P< 0.05). In this study, the results showed that the optimum drying parameters and the highest desirability could be obtained for a treatment using a 60/40 apple puree/malodextrin ratio at 3.5 bar steam pressure and a 1 rpm drum rotation speed. [ABSTRACT FROM AUTHOR]
- Published
- 2020
3. Border (E)scape: collection of research essays
- Author
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Wallis de Vries, J.G., Aragelian, A., Arosio, P.M., Tian, J., Eker, M., Schoo, N.I.W., Deniz, E., Idema, T.C., Ho, C., Topuz, F., Maat, R., Broek, van den, R., Architectural History and Theory, and Built Environment
- Published
- 2014
4. Border (E)scape: collection of research essays
- Author
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Aragelian, A., Arosio, P.M., Tian, J., Wallis de Vries, J.G., Eker, M., Schoo, N.I.W., Deniz, E., Idema, T.C., Ho, C., Topuz, F., Maat, R., Broek, van den, R., Aragelian, A., Arosio, P.M., Tian, J., Wallis de Vries, J.G., Eker, M., Schoo, N.I.W., Deniz, E., Idema, T.C., Ho, C., Topuz, F., Maat, R., and Broek, van den, R.
- Published
- 2014
5. De Vrijplaats: van voormalig militaire mobilisatiecomplex tot vrijplaats in het grensland
- Author
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Topuz, F. and Topuz, F.
- Published
- 2014
6. RESEARCH ON VARIATION OF FEMALE AND MALE FIGS IN TERMS OF LEAF PROPERTIES AND STOMATAL DISTRIBUTION
- Author
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Misirli, A., primary, Topuz, F., additional, and Zeybekoglu, N., additional
- Published
- 1998
- Full Text
- View/download PDF
7. DETERMINATION OF PHENOLIC COMPOUNDS IN MALE AND FEMALE FIGS
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Misirh, A., primary, Gülcan, R., additional, and Topuz, F., additional
- Published
- 1998
- Full Text
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8. Hydrogels in biosensing applications
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Topuz, F., Buenger, D., Tanaka, D., and Jürgen Groll
9. Tailored nanofibrous polyimide-based membranes for highly effective oil spill cleanup in marine ecosystems.
- Author
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Topuz F and Abdulhamid MA
- Subjects
- Adsorption, Petroleum analysis, Hydrophobic and Hydrophilic Interactions, Membranes, Artificial, Imides chemistry, Petroleum Pollution, Nanofibers chemistry, Water Pollutants, Chemical chemistry, Water Pollutants, Chemical analysis, Environmental Restoration and Remediation methods, Ecosystem
- Abstract
Oil spills pose significant environmental threats to marine ecosystems and indirectly affect human health. They are often caused by tanker accidents and pipeline leaks. The persistence of hydrocarbons in the marine environment and their long-term ecological impacts necessitate efficient remediation strategies. Nanofibrous membranes made from polyimides with varying hydrophobicity present a promising solution for oil spill cleanup and oil/water separation. In this study, electrospun nanofibrous membranes were fabricated using 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) combined with 3,5-diamino-2,4,6-trimethylbenzenesulfonic acid (TrMSA) and 2,3,5,6- tetramethyl-p-phenylenediamine (TMPD) to produce bead-free nanofibers at optimized concentrations. These membranes exhibited hydrophobic characteristics and high oil absorption capabilities. The 6FDA-TMPD membrane achieved a maximum adsorption capacity of 76.50 ± 7.32 g g
-1 for Varinca crude oil, while the 6FDA-TrMSA membrane reached 80.05 ± 6.60 g g-1 . In comparison, the commercial 3M™ oil sorbent had a significantly lower capacity of 29.4 ± 3.8 g g-1 for the same oil. The nanofibrous membranes also demonstrated superior performance in adsorbing gasoline and diesel and maintained their effectiveness across multiple cycles, highlighting their potential to mitigate the environmental impact of oil spills., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)- Published
- 2024
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10. Recent Advances in Cyclodextrin-Based Nanoscale Drug Delivery Systems.
- Author
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Topuz F and Uyar T
- Subjects
- Humans, Animals, Nanoparticles chemistry, Nanoparticle Drug Delivery System chemistry, Cyclodextrins chemistry, Drug Delivery Systems
- Abstract
Cyclodextrins (CDs) belong to a class of cyclic oligosaccharides characterized by their toroidal shape consisting of glucose units linked via α-1,4-glycosidic bonds. This distinctive toroidal shape exhibits a dual nature, comprising a hydrophobic interior and a hydrophilic exterior, making CDs highly versatile in various pharmaceutical products. They serve multiple roles: they act as solubilizers, stabilizers, controlled release promoters, enhancers of drug bioavailability, and effective means of masking undesirable tastes and odors. Taking advantage of these inherent benefits, CDs have been integrated into numerous nanoscale drug delivery systems. The resulting nanomaterials exploit the exceptional properties of CDs, including their ability to solubilize hydrophobic drugs for substantial drug loading, engage in supramolecular complexation for engineered nanomaterials, increase bioavailability for improved therapeutic efficacy, stabilize labile drugs, and exhibit biocompatibility and versatility. This paper compiles recent studies on CD functional nanoscale drug delivery platforms. First, we described the physicochemical and toxicological aspects of CDs, CD/drug inclusion complexation, and their impact on improving drug bioavailability. We then summarized applications for CD-functional nano delivery systems based on polymeric, hybrid, lipid-based nanoparticles, and CD-based nanofibers. Particular interest was in the targeted applications and the function of the CD molecules used. In most applications, CD molecules were used for drug solubilization and loading, while in some studies, CD molecules were employed for supramolecular complexation to construct nanoscale drug delivery systems. Finally, the review concludes with a thoughtful consideration of the current challenges and outlook., (© 2024 Wiley Periodicals LLC.)
- Published
- 2024
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11. Dialdehyde carbohydrates - Advanced functional materials for biomedical applications.
- Author
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Falsafi SR, Topuz F, and Rostamabadi H
- Subjects
- Excipients, Hexoses, Hydrogels, Biocompatible Materials, Drug Delivery Systems
- Abstract
Dialdehyde carbohydrates (DCs) have found applications in a wide range of biomedical field due to their great versatility, biocompatibility/biodegradability, biological properties, and controllable chemical/physical characteristics. The presence of dialdehyde groups in carbohydrate structure allows cross-linking of DCs to form versatile architectures serving as interesting matrices for biomedical applications (e.g., drug delivery, tissue engineering, and regenerative medicine). Recently, DCs have noticeably contributed to the development of diverse physical forms of advanced functional biomaterials i.e., bulk architectures (hydrogels, films/coatings, or scaffolds) and nano/-micro formulations. We underline here the current scientific knowledge on DCs, and demonstrate their potential and newly developed biomedical applications. Specifically, an update on the synthesis approach and functional/bioactive attributes is provided, and the selected in vitro/in vivo studies are reviewed comprehensively as examples of the latest progress in the field. Moreover, safety concerns, challenges, and perspectives towards the application of DCs are deliberated., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)
- Published
- 2023
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12. Metal nanoparticles and carbohydrate polymers team up to improve biomedical outcomes.
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Falsafi SR, Topuz F, Bajer D, Mohebi Z, Shafieiuon M, Heydari H, Rawal S, Sathiyaseelan A, Wang MH, Khursheed R, Enayati MH, and Rostamabadi H
- Subjects
- Polymers, Drug Delivery Systems, Tissue Engineering, Carbohydrates, Magnetite Nanoparticles chemistry, Metal Nanoparticles, Nanoparticles
- Abstract
The convergence of carbohydrate polymers and metal nanoparticles (MNPs) holds great promise for biomedical applications. Researchers aim to exploit the capability of carbohydrate matrices to modulate the physicochemical properties of MNPs, promote their therapeutic efficiency, improve targeted drug delivery, and enhance their biocompatibility. Therefore, understanding various attributes of both carbohydrates and MNPs is the key to harnessing them for biomedical applications. The many distinct types of carbohydrate-MNP systems confer unique capabilities for drug delivery, wound healing, tissue engineering, cancer treatment, and even food packaging. Here, we introduce distinct physicochemical/biological properties of carbohydrates and MNPs, and discuss their potentials and shortcomings (alone and in combination) for biomedical applications. We then offer an overview on carbohydrate-MNP systems and how they can be utilized to improve biomedical outcomes. Last but not least, future perspectives toward the application of such systems are highlighted., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)
- Published
- 2023
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13. Encapsulation of antioxidant beta-carotene by cyclodextrin complex electrospun nanofibers: Solubilization and stabilization of beta-carotene by cyclodextrins.
- Author
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Yildiz ZI, Topuz F, Kilic ME, Durgun E, and Uyar T
- Subjects
- Humans, Antioxidants, beta Carotene, Carotenoids, Water, Solubility, Cyclodextrins, Nanofibers
- Abstract
Carotenoids act as effective antioxidant defense systems in humans as they scavenge molecular oxygen and peroxyl radicals. However, their poor water solubility and being susceptible to degradation driven by light and oxygen hinder their bioactivity, therefore, they should be stabilized by host matrices against oxidation. Here, β-carotene was encapsulated in electrospun cyclodextrin (CD) nanofibers to increase its water-solubility and photostability to enhance its antioxidant bioactivity. β-carotene/CD complex aqueous solutions were electrospun into nanofibers. The bead-free morphology of the β-carotene/CD nanofibers was confirmed by SEM. The formation of β-carotene/CD complexes was explored through computational modeling and experimentally by FTIR, XRD and solubility tests. The antioxidant activity of the fibers exposed to UV irradiation was demonstrated via a free radical scavenger assay, where β-carotene/CD nanofibers revealed protection against UV radiation. Overall, this work reports the water-borne electrospinning of antioxidant β-carotene/CD inclusion complex nanofibers, which stabilize the encapsulated β-carotene against UV-mediated oxidation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
- Published
- 2023
- Full Text
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14. Recent trends in the application of protein electrospun fibers for loading food bioactive compounds.
- Author
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Falsafi SR, Topuz F, Esfandiari Z, Can Karaca A, Jafari SM, and Rostamabadi H
- Abstract
Electrospun fibers (EFs) have emerged as promising one-dimensional materials for a myriad of research/commercial applications due to their outstanding structural and physicochemical features. Polymers of either synthetic or natural precursors are applied to design EFs as carriers for bioactive compounds. For engineering food systems, it is crucial to exploit polymers characterized by non-toxicity, non-immunogenicity, biocompatibility, slow/controllable biodegradability, and structural integrity. The unique attributes of protein-based biomaterials endow a wide diversity of desirable features to EFs for meeting the requirements of advanced food/biomedical applications. In this review paper, after an overview on electrospinning, different protein materials (plant- and animal-based) as biodegradable/biocompatible building blocks for designing EFs will be highlighted. The potential application of protein-based EFs in loading bioactive compounds with the intention to inspire interests in both academia and industry will be summarized. This review concludes with a discussion of prevailing challenges in using protein EFs for the bioactive vehicle development., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)
- Published
- 2023
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15. Nursing Image From the Perspective of Healthcare Professionals During the Post-COVID-19 Pandemic Period: A Cross-Sectional Study.
- Author
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Topuz F, Bülbüloğlu S, Filizli Z, and Zayin D
- Abstract
In this study, the goal was achieved to examine the nursing image from the perspective of healthcare professionals in the post-COVID-19 period. This descriptive study was conducted with the participation of n = 264 healthcare professionals working in a training and research hospital. A personal Information Form and Nursing Image Scale were used to collect data. Descriptive methods, the Kruskal-Wallis test, and the Mann-Whitney U test were used in data analysis. Sixty-three point three percent of the healthcare professionals were women and 76.9% were nurses. Sixty-three point six percent of healthcare professionals had COVID-19 and 84.8% had worked without leave during the pandemic. In the post-COVID-19 period, 39% of the healthcare professionals were in partial anxiety and 36.7% were in constant anxiety. Personal characteristics of healthcare professionals did not have a statistical impact on nursing image scale scores. From the perspective of healthcare professionals, the total score of the nursing image scale was moderate. The lack of a strong nursing image may trigger poor care practices., (© 2023 Association for Radiologic & Imaging Nursing. Published by Elsevier Inc. All rights reserved.)
- Published
- 2023
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16. Advances in the development of cyclodextrin-based nanogels/microgels for biomedical applications: Drug delivery and beyond.
- Author
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Topuz F and Uyar T
- Subjects
- Drug Delivery Systems, Excipients chemistry, Humans, Nanogels, Pharmaceutical Preparations, Polymers chemistry, Cyclodextrins chemistry, Microgels, Neoplasms
- Abstract
Nanogels/microgels are swollen cross-linked polymer networks with tunable physicochemical properties and are commonly employed for the effective delivery of hydrophilic drugs. By structural engineering, they can be adapted for the delivery of hydrophobic drugs. Likewise, the use of cyclodextrins (CDs) as pharmaceutical excipients in nanogels drastically boosts the loading capacity of lipophilic drugs while enhancing their stability, bioavailability, and permeability owing to their capability of hosting drugs in their somewhat lipophilic cavity. Here, the synthesis and biomedical applications of CD-based nanogels/microgels were compiled with regard to the CD's role in nanogel synthesis. Even though most applications focused on using CD molecules as functional motifs to carry drugs and construct nanogels for biomedical applications, others used CDs in engineering nanogels to benefit from their supramolecular complexation ability. The applications of CD-based nanogels for drug-mediated cancer/tumor therapy were also discussed. Finally, the review points to the challenges/horizons to boost their biomedical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)
- Published
- 2022
- Full Text
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17. Removal of polycyclic aromatic hydrocarbons (PAHs) from water through degradable polycaprolactone electrospun membrane.
- Author
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Topuz F
- Abstract
Polycyclic aromatic hydrocarbons (PAHs) are common and persistent environmental pollutants produced during the incomplete combustion of fuels. They are known for their carcinogenic and mutagenic properties. Thus, their removal from water bodies is highly crucial and has become a critical issue globally. As a solution, here an electrospun polycaprolactone (PCL) membrane with a mean fiber diameter of 2.74 ± 1.3 μm was produced by electrospinning. Water contact angle (WCA) analysis confirmed the hydrophobic nature of the PCL membrane with a WCA of 124°, which remained stable over time. Differential scanning calorimetry analysis (DSC) revealed the semicrystalline nature of the membrane with the respective melting temperature ( T
m ) of 61.5 °C and crystallization temperature ( Tc ) of 29.6 °C. X-ray diffraction (XRD) analysis demonstrated that the crystalline structure of the PCL membrane could be preserved after electrospinning. Scanning electron microscopy analysis revealed that the membrane could be stretched without any rupture. The PCL membrane was used to scavenge PAHs (i.e. phenanthrene and anthracene) from water; the membrane could reach equilibrium capacity in a few hours, demonstrating the rapid removal of PAHs from water. The adsorption capacities for anthracene and phenanthrene were found to be 173 ± 17 and 560 ± 51 μg/g, respectively. The adsorption data fitted well with the pseudo-first-order kinetics model for both PAH molecules. The sorption could be attributed to hydrophobic adsorption, which allowed using the PCL membrane repeatedly with ethanol exposure to get rid of the adsorbed PAHs from the membrane's surface. The partial degradation of the fibrous membrane in water was observed due to their hydrolysis-induced bulk erosion. However, the degradation was slow for the membrane kept in the air for 3 months. Overall, the PCL membrane with inherent biocompatibility, biodegradability, and good PAH sorption performance is a promising material for water depollution from toxic PAH compounds., (© TÜBİTAK.)- Published
- 2022
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18. Rapid Sublingual Delivery of Piroxicam from Electrospun Cyclodextrin Inclusion Complex Nanofibers.
- Author
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Topuz F
- Abstract
Piroxicam (Px) is a nonsteroidal anti-inflammatory drug (NSAID) used for the treatment of osteoarthritis and rheumatoid arthritis. It is administered orally; however, its poor water solubility causes low loading to the nonconventional drug delivery systems (DDSs), such as electrospun fibers. Furthermore, the rapid dissolution of DDS and fast release of the embedded drugs are crucial for oral delivery of drugs to patients who are unconscious or suffering from dysphagia. In this regard, this study reports the development of rapidly dissolving cyclodextrin (CD)-based inclusion complex (IC) nanofibers by waterborne electrospinning for fast oral delivery of Px. Scanning electron microscopy analysis revealed the formation of bead-free fibers with a mean diameter range of 170-500 nm at various concentrations of Px; increasing the Px loading decreased the fiber diameter. The formation of IC was demonstrated by X-ray diffraction (XRD) analysis by the disappearance of crystalline peaks of Px. Likewise, differential scanning calorimetry (DSC) analysis showed the disappearance of the melting peak of the embedded Px due to IC formation. Both Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) confirmed the presence of Px within the fibers.
1 H NMR experiments demonstrated Px preservation in the fibers after six months. Px-loaded nanofibers were employed for sublingual drug delivery. To mimic the environment of the mouth, the nanofibers were treated with artificial saliva, which revealed the instant dissolution of the nanofibers. Furthermore, dissolution experiments were performed on the tissues wetted with artificial saliva, where the dissolution of the fibers could be extended to a few seconds, demonstrating the suitability of the materials for sublingual oral drug delivery. Overall, this paper, for the first time, reports the rapid oral delivery of Px from polymer-free CD fibers produced by waterborne electrospinning without the requirement of any carrier polymer and toxic solvent., Competing Interests: The author declares no competing financial interest., (© 2022 The Author. Published by American Chemical Society.)- Published
- 2022
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19. Nanofibrous membranes comprising intrinsically microporous polyimides with embedded metal-organic frameworks for capturing volatile organic compounds.
- Author
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Topuz F, Abdulhamid MA, Hardian R, Holtzl T, and Szekely G
- Abstract
Here, we report the fabrication of nanofibrous air-filtration membranes of intrinsically microporous polyimide with metal-organic frameworks (MOFs). The membranes successfully captured VOCs from air. Two polyimides with surface areas up to 500 m
2 g-1 were synthesized, and the impact of the porosity on the sorption kinetics and capacity of the nanofibers were investigated. Two Zr-based MOFs, namely pristine UiO-66 (1071 m2 g-1 ) and defective UiO-66 (1582 m2 g-1 ), were embedded into the nanofibers to produce nanocomposite materials. The nanofibers could remove polar formaldehyde and non-polar toluene, xylene, and mesitylene from air. The highest sorption capacity with 214 mg g-1 was observed for xylene, followed by mesitylene (201 mg g-1 ), toluene (142 mg g-1 ), and formaldehyde (124 mg g-1 ). The incorporation of MOFs drastically improved the sorption performance of the fibers produced from low-surface-area polyimide. Time-dependent sorption tests revealed the rapid sequestration of air pollutants owing to the intrinsic porosity of the polyimides and the MOF fillers. The porosity allowed the rapid diffusion of pollutants into the inner fiber matrix. The molecular level interactions between VOCs and polymer/MOFs were clarified by molecular modeling studies. The practicality of material fabrication and the applicability of the material were assessed through the modification of industrial N95 dust masks. To the best of our knowledge, this is the first successful demonstration of the synergistic combination of intrinsically microporous polyimides and MOFs in the form of electrospun nanofibrous membranes and their application for VOC removal., (Copyright © 2021. Published by Elsevier B.V.)- Published
- 2022
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20. Fast-dissolving antibacterial nanofibers of cyclodextrin/antibiotic inclusion complexes for oral drug delivery.
- Author
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Topuz F, Kilic ME, Durgun E, and Szekely G
- Subjects
- Anti-Bacterial Agents pharmacology, Solubility, Cyclodextrins, Nanofibers, Pharmaceutical Preparations
- Abstract
Hypothesis: The widespread use of antibacterial electrospun nanofibers is mostly restricted due to their low loading capacity to carry antibiotics and the need to use toxic organic solvents to boost the antibiotic loading capacity. Nanofibers based on natural excipients, such as cyclodextrin (CD)-based nanofibers, can carry larger amounts of antibiotics while achieving better stability via inclusion complexation., Experiments: Nanofibers were produced by electrospinning and analyzed by electron microscopy to investigate the morphology of fibers. The formation of inclusion-complexation was analyzed by
1 H NMR, FTIR, and XRD. Thermal analysis of the fibers was done using TGA. Ab initio modeling studies were done to calculate the complexation energies of antibiotics with CD. A disk-diffusion assay was used to test the antibacterial activity of the fibers., Findings: Bead-free antibacterial nanofibers with mean diameters between 340 and 550 nm were produced. The formation of inclusion complexes (IC) between the CD and the antibiotics was confirmed by FTIR and1 H NMR, which was further verified by the disappearance of the crystalline peaks of antibiotics as determined by XRD analysis. Thermal analysis of the nanofibers revealed that the formulations showed good antibiotic encapsulation (45-90%). Ab initio simulations revealed that gentamicin had the highest complexation energy, followed by kanamycin, chloramphenicol, and ampicillin. The antibacterial nanofibers rapidly dissolved in water and artificial saliva, successfully releasing the CD antibiotic complexes. The nanofibers showed high antibacterial activity against Gram-negative Escherichia coli., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)- Published
- 2021
- Full Text
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21. Antioxidant, antibacterial and antifungal electrospun nanofibers for food packaging applications.
- Author
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Topuz F and Uyar T
- Subjects
- Anti-Bacterial Agents chemistry, Antifungal Agents chemistry, Antioxidants chemistry, Food Packaging methods, Nanofibers chemistry, Polyesters chemistry
- Abstract
Food packaging is a multidisciplinary area that encompasses food science and engineering, microbiology, as well as chemistry, and ignited tremendous interest in maintaining the freshness and quality of foods and their raw materials from oxidation and microbial spoilage. With the advances in the packaging industry, they could be engineered as easy-to-open, resealable, active, as well as intelligent with the incorporation of sensory elements while offering desired barrier properties against oxygen and water vapor. In this regard, the use of the electrospinning approach allows producing nanofibrous packaging materials with large surface-to-volume ratios and enables the higher loading of active agents into packaging materials. Electrospun packaging materials have been produced from various polymers (i.e., synthetic and natural) and their (nano)composites, and were mainly exploited for the encapsulation of active agents for their use as active food packaging materials. The electrospinning process was also used for the deposition of electrospun fibers on films to enhance their performance (e.g., as reinforcement material, or to enhance barrier properties). They could be even engineered to provide nutraceuticals to food, or antioxidant, antimicrobial or antifungal protection to the packaged food. In this article, first, introductory descriptions of food packaging, barrier properties, and electrospinning are given. Afterward, active and intelligent food packaging materials are briefly discussed, and the use of electrospinning for the fabrication of active food packaging materials is elaborated. Particular interest has been given to the polymer-type used in the production of electrospun fibers and active properties of the resultant packaging materials (e.g., antioxidant, antibacterial, antifungal). Finally, this review paper concludes with a summary and future outlook towards the development of electrospun food packaging materials., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest to declare., (Copyright © 2019 Elsevier Ltd. All rights reserved.)
- Published
- 2020
- Full Text
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22. Atomic layer deposition of palladium nanoparticles on a functional electrospun poly-cyclodextrin nanoweb as a flexible and reusable heterogeneous nanocatalyst for the reduction of nitroaromatic compounds.
- Author
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Topuz F and Uyar T
- Abstract
We here show a rational approach for the fabrication of a flexible, insoluble catalytic electrospun nanoweb of cross-linked cyclodextrin (CD) for the reduction of nitroaromatics. CD nanofibers were produced by electrospinning an aqueous HP-β-CD solution containing a multifunctional cross-linker ( i.e. , 1,2,3,4-butanetetracarboxylic acid, BTCA) and were subsequently cross-linked by heat treatment, which led to an insoluble electrospun poly-CD nanoweb. The poly-CD nanoweb was decorated with Pd nanoparticles (Pd-NPs) by atomic layer deposition (ALD) technique over 20 cycles to give rise to a catalytic electrospun nanoweb ( i.e. , Pd@poly-CD). The formation of the Pd-NPs on the poly-CD nanofiber surface was clearly evidenced by TEM and STEM imaging, which displayed the homogeneously distributed Pd-NPs with a mean size of 4.34 nm. ICP-MS analysis revealed that the Pd content on the Pd@poly-CD nanoweb was 0.039 mg per mg of nanoweb. The catalytic performance of the Pd@poly-CD nanoweb was tested for the reduction of a nitroaromatic compound ( i.e. , 4-nitrophenol (4-NP)), and high catalytic performance of the Pd@poly-CD nanoweb was observed with a corresponding TOF value of 0.0316 min
-1 . XPS was used to explore the oxidation state of Pd atoms before and after the catalytic reduction of 4-NP, and no significant change was observed after catalytic reactions. In brief, the Pd@poly-CD nanoweb having handy, flexible, structural stability and reusability can be effectively used in environmental applications as a heterogeneous nanocatalyst for the reduction of toxic nitroaromatics., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2019
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23. RNA-mediated, green synthesis of palladium nanodendrites for catalytic reduction of nitroarenes.
- Author
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Topuz F and Uyar T
- Subjects
- Bromides chemistry, Catalysis, Kinetics, Nitrophenols chemistry, Oxidation-Reduction, Particle Size, Potassium Compounds chemistry, Povidone chemistry, RNA chemistry, Surface Properties, Trinitrotoluene chemistry, Dendrites chemistry, Metal Nanoparticles chemistry, Nanoparticles chemistry, Palladium chemistry
- Abstract
Palladium (Pd)-catalyzed reactions mostly show structure sensitivity: i.e., the selectivity and activity of the reactions are highly dependent on the arrangement of Pd atoms. In this regard, branched Pd nanoparticles show enhanced catalytic performance owing to the presence of low coordinated Pd atoms. In this paper, a novel solution-phase synthesis of flower-like Pd nanodendrites using ribonucleic acid (RNA) as a capping agent and ascorbic acid as a reducing agent was described. On the other hand, the co-use of polyvinylpyrrolidone (PVP) and potassium bromide (KBr) instead of RNA at the same synthesis conditions led to cuboid nanoparticles, while the sole use of ascorbic acid resulted in faceted nanoparticles. The formation of nanodendritic morphology was attributed to the RNA-assisted growth through particle attachment. This scenario was supported by TEM analysis that demonstrated the aggregation of small particles to form larger nanoparticles at the onset of the reaction. The shape and size of the nanoparticles could be readily tuned by the RNA content used. XPS confirmed the formation of metallic Pd nanoparticles. The presence of crystalline planes of {1 1 1}, {2 0 0}, {2 2 0}, {3 1 1} and {2 2 2} was demonstrated by XRD and SAED analyses. The Pd nanodendrites were used for the reduction of p-nitrophenol (PNP) and 2,4,6-trinitrotoluene (TNT), and reduction rate constants (k) were calculated as 1.078 min
-1 (normalized rate constant, knor = 59.66 mmol-1 s-1 ) for PNP and 0.3181 min-1 (knor = 17.6 mmol-1 s-1 ) for TNT with the corresponding turnover frequencies (TOFs) as 16.06 and 40.80 h-1 , respectively., (Copyright © 2019 Elsevier Inc. All rights reserved.)- Published
- 2019
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24. Efficient Removal of Polycyclic Aromatic Hydrocarbons and Heavy Metals from Water by Electrospun Nanofibrous Polycyclodextrin Membranes.
- Author
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Celebioglu A, Topuz F, Yildiz ZI, and Uyar T
- Abstract
Here, a highly efficient membrane based on electrospun polycyclodextrin (poly-CD) nanofibers was prepared and exploited for the scavenging of various polycyclic aromatic hydrocarbons (PAHs) and heavy metals from water. The poly-CD nanofibers were produced by the electrospinning of CD molecules in the presence of a cross-linker (i.e., 1,2,3,4-butanetetracarboxylic acid), followed by heat treatment to obtain an insoluble poly-CD nanofibrous membrane. The membrane was used for the removal of several PAH compounds (i.e., acenaphthene, fluorene, fluoranthene, phenanthrene, and pyrene) and heavy metals (i.e., Pb
2+ , Ni2+ , Mn2+ , Cd2+ , Zn2+ , and Cu2+ ) from water over time. Experiments were made on the batch sorption of PAHs and heavy metals from contaminated water to explore the binding affinity of PAHs and heavy metals to the poly-CD membrane. The equilibrium sorption capacity ( qe ) of the poly-CD nanofibrous membrane was found to be 0.43 ± 0.045 mg/g for PAHs and 4.54 ± 0.063 mg/g for heavy metals, and the sorption kinetics fitted well with the pseudo-second-order model for both types of pollutants. The membrane could be recycled after treatment with acetonitrile or a 2% nitric acid solution and reused up to four times with similar performance. Further, dead-end filtration experiments showed that the PAH removal efficiencies were as high as 92.6 ± 1.6 and 89.9 ± 4.8% in 40 s for the solutions of 400 and 600 μg/L PAHs, respectively. On the other hand, the removal efficiencies for heavy metals during the filtration were 94.3 ± 5.3 and 72.4 ± 23.4% for 10 and 50 mg/L solutions, respectively, suggesting rapid and efficient filtration of heavy metals and PAHs by the nanofibrous poly-CD membrane., Competing Interests: The authors declare no competing financial interest.- Published
- 2019
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25. One-step green synthesis of antibacterial silver nanoparticles embedded in electrospun cyclodextrin nanofibers.
- Author
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Celebioglu A, Topuz F, Yildiz ZI, and Uyar T
- Subjects
- Anti-Bacterial Agents chemical synthesis, Anti-Bacterial Agents chemistry, Cyclodextrins chemistry, Escherichia coli drug effects, Green Chemistry Technology methods, Particle Size, Silver chemistry, Staphylococcus aureus drug effects, Anti-Bacterial Agents pharmacology, Cyclodextrins pharmacology, Metal Nanoparticles chemistry, Nanocomposites chemistry, Nanofibers chemistry, Silver pharmacology
- Abstract
Antibacterial electrospun nanofibers based on cyclodextrin (CD) and silver nanoparticles (Ag-NPs) were produced by solution electrospinning from aqueous and DMF solutions using different Ag contents. CD molecules acted as the reducing agent and catalyzed the formation of Ag-NPs. The nanofibers with smaller diameters were observed for the fibers generated from DMF solutions than those produced from aqueous solutions. TEM and STEM analyses revealed the Ag-NPs (∼2-5 nm depending on solvent-type and Ag loading) in nanofibers, while FTIR and surface enhanced Raman scattering (SERS) analyses showed the apparent frequency shift of OH stretching band and the enhancement of Raman bands of CD molecules with the incorporation of the Ag-NPs. The polycrystalline structure of the Ag-NPs was shown by XRD and SAED analyses over {111}, {200}, {220} and {311} planes. The nanofibers showed significant inhibition against the growth of Escherichia coli and Staphylococcus aureus owing to the antibacterial activity of the Ag-NPs., (Copyright © 2018 Elsevier Ltd. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
26. Nanocomposite Bioinks Based on Agarose and 2D Nanosilicates with Tunable Flow Properties and Bioactivity for 3D Bioprinting.
- Author
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Nadernezhad A, Caliskan OS, Topuz F, Afghah F, Erman B, and Koc B
- Abstract
Three-dimensional (3D) bioprinting enables the controlled fabrication of complex constructs for tissue engineering applications and has been actively explored in recent years. However, its progress has been limited by the existing difficulties in the development of bioinks with suitable biocompatibility and mechanical properties and at the same time adaptability to the process. Herein, we describe the engineering of a nanocomposite agarose bioink with tailored properties using 2D nanosilicate additives. The suitability of agarose for 3D bioprinting has been debated due to its bioinert nature and compatibility with extrusion-based bioprinting. Nanosilicates were used to tailor the flow behavior of agarose solutions, and detailed rheological characterization of different bioink formulations was performed to elucidate the effect of nanosilicates on the flow behavior and gelation of agarose bioinks. The proper selection of nanosilicate concentration resulted in extrusion 3D printed structures with high shape fidelity and structural integrity. Moreover, the influence of addition of nanosilicates on the bioactivity of agarose was studied, and nanocomposite bioinks showed significant improvement in metabolic activity of encapsulated cells. The bioactivity of the nanocomposite bioinks was also evaluated through a cell spreading assay; the charged surfaces of nanosilicates resulted in full spreading and elongation of fibroblasts, and the extent of change in morphology of cells was found to be directly correlated with the nanosilicate concentration. Our findings suggested that engineered agarose-nanosilicate bioinks can be exploited as a new generation of hydrogel bioinks for extrusion 3D bioprinting with tunable flow properties and bioactivity.
- Published
- 2019
- Full Text
- View/download PDF
27. Influence of Hydrogen-Bonding Additives on Electrospinning of Cyclodextrin Nanofibers.
- Author
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Topuz F and Uyar T
- Abstract
The electrospinning of highly concentrated solutions of cyclodextrin (CD) leads to bead-free nanofibers without the need of a polymeric carrier. The occurrence of numerous hydrogen bonds among CD molecules is the main driving force for their electrospinning, and hence, additives with hydrogen-bonding potential can disturb the aggregation of CD molecules and affect their electrospinning. In this study, we systematically investigated the influence of five different hydrogen-bonding additives, i.e., methylamine (MA), ethylenediamine (ED), urea, 2,2,2-trifluoroethanol (TFE), and 1,1,1,3,3,3-hexafluoroisopropanol (HFIP), on the solution behavior of hydroxypropyl-β-CD (HP-β-CD) by rheology, conductivity, and NMR analyses, and the morphology of the electrospun HP-β-CD nanofibers by scanning electron microscopy. The
1 H NMR chemical shifts of the HP-β-CD protons in D2 O were observed with the incorporation of hydrogen-bonding molecules due to the occurrence of intermolecular associations between HP-β-CD and additives. Dynamic light scattering measurements revealed a clear decrease in the aggregate size with the introduction of additives. Unlike other additives, which showed a general decreasing trend in viscosity with increasing additive content, the addition of MA led to a significant increase in the viscosity with increasing concentration and gave rise to HP-β-CD nanofibers at lower concentrations. The addition of low concentrations of ED, urea, TFE, and HFIP led to thinner nanofibers due to the lower viscosity of the respective solutions. Increasing additive content deteriorated the electrospinnability of HP-β-CD solutions, resulting in beaded fibers. A systematic relationship was found between the solution viscosity and morphology of the respective electrospun fibers. Overall, this study, for the first time, reports the influence of hydrogen bonding on the polymer-free electrospinning of CD molecules and shows a correlation between solution properties and morphology of their electrospun nanofibers., Competing Interests: The authors declare no competing financial interest.- Published
- 2018
- Full Text
- View/download PDF
28. Electrospinning of Cyclodextrin Functional Nanofibers for Drug Delivery Applications.
- Author
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Topuz F and Uyar T
- Abstract
Electrospun nanofibers have sparked tremendous attention in drug delivery since they can offer high specific surface area, tailored release of drugs, controlled surface chemistry for preferred protein adsorption, and tunable porosity. Several functional motifs were incorporated into electrospun nanofibers to greatly expand their drug loading capacity or to provide the sustained release of the embedded drug molecules. In this regard, cyclodextrins (CyD) are considered as ideal drug carrier molecules as they are natural, edible, and biocompatible compounds with a truncated cone-shape with a relatively hydrophobic cavity interior for complexation with hydrophobic drugs and a hydrophilic exterior to increase the water-solubility of drugs. Further, the formation of CyD-drug inclusion complexes can protect drug molecules from physiological degradation, or elimination and thus increases the stability and bioavailability of drugs, of which the release takes place with time, accompanied by fiber degradation. In this review, we summarize studies related to CyD-functional electrospun nanofibers for drug delivery applications. The review begins with an introductory description of electrospinning; the structure, properties, and toxicology of CyD; and CyD-drug complexation. Thereafter, the release of various drug molecules from CyD-functional electrospun nanofibers is provided in subsequent sections. The review concludes with a summary and outlook on material strategies.
- Published
- 2018
- Full Text
- View/download PDF
29. Nanosilicate embedded agarose hydrogels with improved bioactivity.
- Author
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Topuz F, Nadernezhad A, Caliskan OS, Menceloglu YZ, and Koc B
- Subjects
- Animals, Cells, Immobilized cytology, Materials Testing, Mice, NIH 3T3 Cells, Cell Proliferation, Cells, Immobilized metabolism, Hydrogels chemistry, Nanocomposites chemistry, Sepharose chemistry, Silicates chemistry
- Abstract
This paper reports the synthesis of nanocomposite agarose hydrogels with improved bioactivity with the incorporation of anisotropic 2D nanosilicates (Laponite) to promote cell binding, growth and proliferation. Rheological measurements showed that the incorporation of nanosilicates slightly increased the gelation temperature (T
gel ). The use of higher nanosilicate content at the constant agarose concentration improved the mechanical properties of the gels. Due to the non-swelling nature of agarose, the addition of nanosilicates did not result in any remarkable change in the swelling properties of the agarose gels, while collapsed agarose nanofibers were observed with the incorporation of nanosilicates. EDX analysis confirmed the presence of the embedded nanosilicates in the gel matrix. The existence of physical interactions between nanosilicate and agarose was demonstrated by FTIR over the shifting of SiO stretching band to a lower frequency. The encapsulated NIH/3T3 fibroblast cells showed enhanced proliferation and spreading in the presence of nanosilicates., (Copyright © 2018 Elsevier Ltd. All rights reserved.)- Published
- 2018
- Full Text
- View/download PDF
30. Cyclodextrin-assisted synthesis of tailored mesoporous silica nanoparticles.
- Author
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Topuz F and Uyar T
- Abstract
Mesoporous silica nanoparticles (MSNs) have sparked considerable interest in drug/gene delivery, catalysis, adsorption, separation, sensing, antireflection coatings and bioimaging because of their tunable structural properties. The shape, size and pore structure of MSNs are greatly influenced by the type of additives used, e.g., solvent and pore-templating agent. Here, we studied the influence of cyclodextrin (CD) molecules on the formation of MSNs. The nanoparticles over 100 nm in diameter were synthesized by surfactant-templated, hydrolysis-polycondensation reactions in the presence of pristine CD (β-CD) or hydroxypropyl-functionalized CDs (HP-γ-CD and HP-β-CD). Depending on the formulation conditions, differently shaped MSNs, such as bean-like, spherical, ellipsoid, aggregate and faceted were generated. The morphology and size of MSNs varied with the CD-type used. Generally, spherical particles were obtained with β-CD, while a faceted morphology was observed for the particles synthesized using HP-CDs. The particle size could be tuned by adjusting the amount of CD used; increasing the CD concentration led to larger particles. MSNs synthesized in the presence of β-CD displayed a smaller particle size than those produced with HP-functional CDs. FTIR, TGA and solid-state
13 C NMR demonstrated the adsorption of CDs on the particle surfaces. The proposed concept allows for the synthesis of silica nanoparticles with control over particle shape and size by adjusting the concentration of additives in a simple, one-pot reaction system for a wide range of applications.- Published
- 2018
- Full Text
- View/download PDF
31. Electrospinning of gelatin with tunable fiber morphology from round to flat/ribbon.
- Author
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Topuz F and Uyar T
- Subjects
- Nanofibers, Solvents, Gelatin chemistry
- Abstract
The electrospinning of gelatin with tunable fiber morphology from round to flat/ribbon was shown, and the detailed studies were conducted to correlate the fiber morphology with electrospinning process parameters and gelatin concentration in electrospinning solution. Particularly, variations in the applied voltage and the concentration of gelatin led to the transition of fiber shape from round to flat/ribbon. The formation of flat-shaped fibers was attributed to rapid evaporation of the solvent (formic acid) from the fiber matrix with increasing the applied voltage and gelatin concentration. On the other hand, round fibers were due to the steady evaporation of formic acid throughout the cross-section of fibers. WAXS analysis revealed that the loss of triple-helical crystalline structure in gelatin after the electrospinning process. The gelatin fibers were cross-linked through treatment with toluene 2,4-diisocyanate (TDI) in a mixed solution of acetone and pyridine, and XPS confirmed the cross-linking of the fibers over an increased carbon content on the elemental composition of the fiber surface due to the incorporated TDI moieties. Overall, this study focuses on morphological tuning of gelatin electrospun fibers towards a flat/ribbon-like structure by variation of electrospinning parameters and polymer concentration, and thus, the proposed concept can be adapted towards flattened/ribbon-like fibers of other protein-based systems by electrospinning., (Copyright © 2017 Elsevier B.V. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
32. Poly-cyclodextrin cryogels with aligned porous structure for removal of polycyclic aromatic hydrocarbons (PAHs) from water.
- Author
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Topuz F and Uyar T
- Abstract
Cyclodextrins (CDs) are sugar-based cyclic oligosaccharides, which form inclusion complexes with small guest molecules through their hydrophobic cavity. Here we successfully synthesized highly porous poly-cyclodextrin (poly-CD) cryogels, which were produced under cryogenic conditions by the cross-linking of amine-functional CDs with PEG-based diepoxide cross-linker. The poly-CD cryogels showed aligned porous network structures owing to the directional freezing of the matrix, of which the pore size and architecture exposed variations depending on the composition of the reactants. The cryogels were employed for the removal of genotoxic polycyclic aromatic hydrocarbons (PAHs) from aqueous solutions. They reached PAH sorption capacities as high as 1.25mg PAH per gram cryogel. This high sorption performance is due to interactions between PAHs and the complete swollen network, and thus, is not restricted by interfacial adsorption. Given that the hydrophilic nature of the components, the sorption performance could only be attributed to the inclusion complex formation of CDs with PAH molecules. The poly-CD cryogels could be recycled with an exposure to ethanol and reused without any significant loss in the sorption capacity of PAHs., (Copyright © 2017 Elsevier B.V. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
33. Cyclodextrin-functionalized mesostructured silica nanoparticles for removal of polycyclic aromatic hydrocarbons.
- Author
-
Topuz F and Uyar T
- Subjects
- Adsorption, Polycyclic Aromatic Hydrocarbons chemistry, Cyclodextrins chemistry, Metal Nanoparticles chemistry, Polycyclic Aromatic Hydrocarbons isolation & purification, Silicon Dioxide chemistry
- Abstract
Polycyclic aromatic hydrocarbons (PAHs) are the byproducts of the incomplete combustion of carbon-based fuels, and have high affinity towards DNA strands, ultimately exerting their carcinogenic effects. They are ubiquitousenvironmental contaminants,and can accumulate on tissues due to their lipophilic nature. In this article, we describe a novel concept for PAH removal from aqueous solutions using cyclodextrin-functionalized mesostructured silica nanoparticles (CDMSNs) and pristine mesostructured silica nanoparticles (MSNs). The adsorption applications of MSNs are greatly restricted due to the absence of surface functional groups on such particles. In this regard, cyclodextrins can serve as ideal functional molecules with their toroidal, cone-type structure, capable of inclusion-complex formation with many hydrophobic molecules, including genotoxic PAHs. The CDMSNs were synthesized by the surfactant-templated, NaOH-catalyzed condensation reactions of tetraethyl orthosilicate (TEOS) in the presence of two different types of cyclodextrin (i.e. hydroxypropyl-β-cyclodextrin (HP-β-CD) and native β-cyclodextrin (β-CD)). The physical incorporation of CD moieties was supported by XPS, FT-IR, NMR, TGA and solid-state
13 C NMR. The CDMSNs were treated with aqueous solutions of five different PAHs (e.g. pyrene, anthracene, phenanthrene, fluorene and fluoranthene). The functionalization of MSNs with cyclodextrin moieties significantly boosted the sorption capacity (q) of the MSNs up to ∼2-fold, and the q ranged between 0.3 and 1.65mg per gram CDMSNs, of which the performance was comparable to that of the activated carbon., (Copyright © 2017 Elsevier Inc. All rights reserved.)- Published
- 2017
- Full Text
- View/download PDF
34. One-Step Fabrication of Biocompatible Multifaceted Nanocomposite Gels and Nanolayers.
- Author
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Topuz F, Bartneck M, Pan Y, and Tacke F
- Subjects
- Animals, Cell Adhesion, Cells, Cultured, Mice, Tissue Engineering, Biocompatible Materials chemistry, Hydrogels chemistry, Macrophages cytology, Nanocomposites chemistry, Polymers chemistry
- Abstract
Nanocomposite gels are a fascinating class of polymeric materials with an integrative assembly of organic molecules and organic/inorganic nanoparticles, offering a unique hybrid network with synergistic properties. The mechanical properties of such networks are similar to those of natural tissues, which make them ideal biomaterial candidates for tissue engineering applications. Existing nanocomposite gel systems, however, lack many desirable gel properties, and their suitability for surface coatings is often limited. To address this issue, this article aims at generating multifunctional nanocomposite gels that are injectable with an appropriate time window, functional with bicyclononynes (BCN), biocompatible and slowly degradable, and possess high mechanical strength. Further, the in situ network-forming property of the proposed system allows the fabrication of ultrathin nanocomposite coatings in the submicrometer range with tunable wettability and roughness. Multifunctional nanocomposite gels were fabricated under cytocompatible conditions (pH 7.4 and T = 37 °C) using laponite clays, isocyanate (NCO)-terminated sP(EO-stat-PO) macromers, and clickable BCN. Several characterization techniques were employed to elucidate the structure-property relationships of the gels. Even though the NCO-sP(EO-stat-PO) macromers could form a hydrogel network in situ on contact with water, the incorporation of laponite led to significant improvement of the mechanical properties. BCN motifs with carbamate links were used for a metal-free click ligation with azide-functional molecules, and the subsequent gradual release of the tethered molecules through the hydrolysis of carbamate bonds was shown. The biocompatibility of the hydrogels was examined through murine macrophages, showing that the material composition strongly affects cell behavior.
- Published
- 2017
- Full Text
- View/download PDF
35. Novel bibliometric scores for evaluating research quality and output: a correlation study with established indexes.
- Author
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Scotti V, De Silvestri A, Scudeller L, Abele P, Topuz F, and Curti M
- Subjects
- Humans, Journal Impact Factor, Publishing statistics & numerical data, Research standards, Bibliometrics, Publishing standards
- Abstract
Introduction: Novel bibliometric indexes (commonly known as altmetrics) are gaining interest within the scientific community and might represent an important alternative measure of research quality and output., Aims: We evaluate how these new metrics correlate with established bibliometric indexes such as the impact factor (IF), currently used as a measure of scientific production as well as a criterion for scientific research funding, and how they might be helpful in assessing the impact of research., Methods: We calculated altmetrics scores for all the articles published at our institution during a single year and examined the correlation between altmetrics scores and IFs as a measure of research quality and impact in all departments., Results: For all articles from the various departments published in a single year, the altmetrics score and the sum of all IFs showed a strong and significant correlation (Spearman's rho 0.88). The correlation was significant also when the major components of altmetrics, including Facebook, Twitter and Mendeley, were analyzed. The implementation of altmetrics has been found to be easy and effective at both the researcher and librarian levels., Conclusions: The novel bibliographic index altmetrics is consistent and reliable and can complement or be considered a valid alternative to standard bibliometric indexes to benchmark output and quality of research for academic and funding purposes.
- Published
- 2016
- Full Text
- View/download PDF
36. DNA Nanogels To Snare Carcinogens: A Bioinspired Generic Approach with High Efficiency.
- Author
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Topuz F, Singh S, Albrecht K, Möller M, and Groll J
- Subjects
- Adsorption, Circular Dichroism, DNA Adducts chemistry, Nanogels, Water Pollutants, Chemical chemistry, Carcinogens chemistry, DNA chemistry, Polycyclic Aromatic Hydrocarbons chemistry, Polyethylene Glycols chemistry, Polyethyleneimine chemistry
- Abstract
Polycyclic aromatic hydrocarbons (PAHs) are combustion-related pollutants and are ubiquitous in the environment, including in sources of drinking water. Upon contact with DNA, stable PAH-DNA adducts form rapidly as the first step towards their toxic effects. In this work, we prepared hydrophilic DNA nanogels to exploit this generic complexation process as a biomimetic scavenging method. This approach relies on interaction between PAHs and the complete network that constitutes the water-swollen nanogels, and is not restricted to interfacial adsorption. Up to 720 μg of PAH per gram of DNA nanogel are taken up, meaning that 1 mg of DNA nanogel is sufficient to purify a liter of water containing the critical PAH concentration for cancer risk (600 ng L(-1) ). As a result of short diffusion pathways, PAH uptake is rapid, reaching 50 % loading after 15 minutes. Beyond PAHs, DNA nanogels may be useful for the generic detoxification of water containing genotoxins, since most known molecules that strongly associate with DNA are mutagenic., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2016
- Full Text
- View/download PDF
37. Molecular response of liver sinusoidal endothelial cells on hydrogels.
- Author
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Bartneck M, Topuz F, Tag CG, Sauer-Lehnen S, Warzecha KT, Trautwein C, Weiskirchen R, and Tacke F
- Subjects
- Animals, Cells, Cultured, Immunomagnetic Separation methods, Male, Materials Testing, Mice, Mice, Inbred C57BL, Neovascularization, Physiologic physiology, Cell Adhesion Molecules metabolism, Cell Separation methods, Endothelial Cells cytology, Endothelial Cells metabolism, Hydrogels chemistry, Liver cytology
- Abstract
There is a high demand for the isolation of primary endothelial cells for biomaterial endotheliazation studies, tissue engineering, and artificial organ development. Further, biomarkers for monitoring the response of endothelial cells in biomaterials science are required. We systematically compared two strategies for isolating liver sinusoidal endothelial cells (LSEC) from mouse liver. We demonstrate that fluorescence-activated cell sorting results in a considerably higher purity (~97%) compared to magnetic-assisted cell sorting (~80%), but is associated with a lower yield and recovery rate. Cell repellent polyethylene glycol (PEG) substrates affected the morphology of primary LSEC in culture and significantly downregulated the intracellular adhesion molecule (ICAM) and upregulated the vascular cell adhesion molecule (VCAM). This molecular response could partially be reverted by further modification with arginylglycylaspartic acid (RGD). Thus, usage of PEGylated materials may reduce, while applying RGD may support endotheliazation of materials, and we could relate LSEC attachment to their expression of ICAM and VCAM mRNA, suggesting their usage as biomarkers for endothelialization., (Copyright © 2015. Published by Elsevier B.V.)
- Published
- 2015
- Full Text
- View/download PDF
38. Embedding of active proteins and living cells in redox-sensitive hydrogels and nanogels through enzymatic cross-linking.
- Author
-
Singh S, Topuz F, Hahn K, Albrecht K, and Groll J
- Subjects
- Microscopy, Electron, Scanning, Nanogels, Oxidation-Reduction, beta-Galactosidase chemistry, Cross-Linking Reagents chemistry, Hydrogels chemistry, Polyethylene Glycols chemistry, Polyethyleneimine chemistry, Proteins chemistry
- Published
- 2013
- Full Text
- View/download PDF
39. Formation of hydrogels by simultaneous denaturation and cross-linking of DNA.
- Author
-
Topuz F and Okay O
- Subjects
- Cross-Linking Reagents, Epoxy Resins, Nucleic Acid Denaturation, Polyethylene Glycols, DNA chemistry, Hydrogels chemical synthesis
- Abstract
DNA hydrogels with a wide range of tunable properties are desirable for applications to make use the characteristics of DNA. This study describes formation conditions of DNA hydrogels using ethylene glycol diglycidyl ether (EGDE) cross-linker and N,N,N',N'-tetramethylethylenediamine (TEMED) catalyst under various reaction conditions. Rheological measurements indicate that the cross-linking of DNA in semidilute solutions proceeds by alternate gel-sol and sol-gel transitions due to two antagonistic effects of EGDE-TEMED pair; the one destroying the physical bonds (denaturation), the other creating chemical bonds (cross-linking). The viscoelastic properties of the hydrogels and the conformation of DNA network chains could be tuned by adjusting the synthesis parameters. Increasing concentration of DNA at the gel preparation stabilizes its structure so that double stranded (ds-) DNA hydrogels form. The average distance between the effective cross-links in single stranded DNA gel is much larger than that in ds-DNA gel making the former gel stable in aqueous solutions. Creep-recovery tests show that heating a semidilute solution of DNA above the DNA melting temperature (87.5 degrees C) and subsequently cooling down to 25 degrees C increases the elastic response of the solution and produces an elastic DNA mesh. DNA hydrogel undergoes a volume phase transition in aqueous solutions of polyethylene glycol's at which the gel changes about 5 times its volume.
- Published
- 2009
- Full Text
- View/download PDF
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