Biyomühendislik Bölümü Koleksiyonu

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https://hdl.handle.net/20.500.12428/2631

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Preparation of composite hydrogels containing fly ash as low-cost adsorbent material and its use in dye adsorption
(Springer Science and Business Media Deutschland GmbH, 2022) Önder, Alper; Ilgın, Pınar; Özay, Hava; Özay, Özgür
Abstract: Recycling industrial wastes is necessary for the economy and the environment. Additionally, it is important to develop high-efficiency adsorbents to prevent severe water pollution caused by wastewater containing dye agents. Here, poly(2-acrylamido-2-methylpropane sulfonic acid)-fly ash composite hydrogel was synthesized with a variety of fly ash proportions with the radical polymerization method. The synthesized composite hydrogel was used for adsorption of methylene blue and methyl orange dyes from water containing dye agents. A variety of parameters such as initial dye concentration, solution pH, anion effects, temperature, contact time and adsorbent amount were investigated for optimization of the adsorption process. The poly(2-acrylamido-2-methylpropane sulfonic acid)-fly ash composite hydrogel was determined to be an effective adsorbent to remove both the cationic dye methylene blue (1438.68 mg g−1) and the anionic dye methyl orange (646.54 mg g−1). Experimental adsorption data were assessed with a variety of isotherm and kinetic models. It was determined that the adsorption of both dye molecules abided by the pseudo-second-order kinetic model. The thermodynamic parameters were determined as ΔH° = − 15.77 ± 5.22 kJ mol−1, ΔS = − 45.05 ± 16.42 J mol−1 K−1 and ΔG° < 0 for MB, ΔH° = − 20.13 ± 4.83 kJ mol−1, ΔS = − 72.87 ± 15.20 J mol−1 K−1 and ΔG° > 0 for MO. In conclusion, a material was synthesized that can be used as a single adsorbent composite material for both anionic and cationic dyes. In addition to the perfect adsorption capacity of this material, it offers reusability and a broad area of application for a variety of dye agents.
Super Porous Carboxymethyl Cellulose–Tannic Acid (TA@CMC) Cryogels with Antioxidant, Antibacterial, and α-Glucosidase Enzyme Inhibition Abilities
(Mdpi, 2024) Şahiner, Mehtap; Demirci, Şahin; Şahiner, Nurettin
Here, super porous carboxymethyl cellulose (CMC) cryogels were synthesized in 10-100% crosslinker and the presence of TA, at varying amounts of TA, e.g., 10 and 25 wt% of CMC under cryogenic conditions (-20 degrees C) as TA@CMCs. To control the degradation of CMC cryogel networks, the crosslinking ratio of divinyl sulfone (DVS:X) to CMC varied at 10, 25, 50, and 100% moles of the CMC repeating unit. Higher hydrolytic degradation was observed for CMC 10%X cryogels at pH 1.0 with 28.4 +/- 1.2% weight loss. On the other hand, the TA-release studies from TA@CMC-based cryogels showed that higher TA releases were observed for both TA@CMC 10% and 25% cryogels at pH 7.4, with 23.6 +/- 1.1, and 46.5 +/- 2.3 mg/g in 480 min, which are equal to almost 24% and 18% of the TA contents of the corresponding cryogels, respectively. The antioxidant properties of TA@CMC cryogels were examined, and worthy antioxidant properties were observed due to the TA. The alpha-glucosidase enzyme inhibition ability of the prepared cryogels was examined at different concentrations by grinding cryogels, and it was determined that TA@CMC 25% cryogel at 3 mg/mL concentration inhibited 70.4 + 1.3% of the enzyme. All bare CMC-based cryogels were found to be non-hemolytic with a less than 1% hemolysis ratio and also effective on the blood coagulation mechanism with blood-clotting index (BCI) values between 62.1 and 81.7% at 1 mg/mL concentrations. On the other hand, TA@CMC 25% cryogels exhibited a slight hemolytic profile with a 6.1 +/- 0.8% hemolysis ratio and did not affect the blood coagulation mechanism with 97.8 +/- 0.4% BCI value.
Light-Activated Modified Arginine Carbon Dots as Antibacterial Particles
(Mdpi, 2022) Sağbaş Suner, Selin; Şahiner, Mehtap; Yılmaz, Aynur Sanem; Ayyala, Ramesh S.; Şahiner, Nurettin
Nitrogen-doped arginine carbon dots (Arg CDs) as light-sensitive antibacterial agents were prepared by using citric acid as the carbon source and arginine amino acid as the nitrogen source via a microwave-assisted synthesis method. Dynamic light scattering (DLS) measurements and TEM images revealed that the Arg CDs were in the 1-10 nm size range with a graphitic structure. To improve their antibacterial capability, the Arg CDs were modified with ethyleneimine (EDA), pentaethylenehexamine (PEHA), and polyethyleneimine (PEI) as different amine sources, and the zeta potential value of +2.8 +/- 0.6 mV for Arg CDs was increased to +34.4 +/- 4.1 mV for PEI-modified Arg CDs. The fluorescence intensity of the Arg CDs was significantly enhanced after the modification with EDA, and the highest antibacterial effect was observed for the PEI-modified Arg CDs. Furthermore, the photodynamic antibacterial capacity of bare and EDA-modified Arg CDs was determined upon light exposure to show their light-induced antibacterial effects. Photoexcited (315-400 nm, UVA, 300 W), EDA-modified Arg CDs at 5 mg/mL concentration were found to inhibit about 49 +/- 7% of pathogenic bacteria, e.g., Escherichia coli, with 5 min of light exposure. Furthermore, the biocompatibilities of the bare and modified Arg CDs were also investigated with blood compatibility tests via hemolysis and blood clotting assays and cytotoxicity analysis on L929 fibroblast cells.
Degradable and Non-Degradable Chondroitin Sulfate Particles with the Controlled Antibiotic Release for Bacterial Infections
(Mdpi, 2022) Sağbaş Suner, Selin; Şahiner, Mehtap; Ayyala, Ramesh S.; Şahiner, Nurettin
Non-degradable, slightly degradable, and completely degradable micro/nanoparticles derived from chondroitin sulfate (CS) were synthesized through crosslinking reactions at 50%, 40%, and 20% mole ratios, respectively. The CS particles with a 20% crosslinking ratio show total degradation within 48 h, whereas 50% CS particles were highly stable for up to 240 h with only 7.0 +/- 2.8% weight loss in physiological conditions (pH 7.4, 37 degrees C). Tobramycin and amikacin antibiotics were encapsulated into non-degradable CS particles with high loading at 250 g/mg for the treatment of corneal bacterial ulcers. The highest release capacity of 92 +/- 2% was obtained for CS-Amikacin particles with sustainable and long-term release profiles. The antibacterial effects of CS particles loaded with 2.5 mg of antibiotic continued to render a prolonged release time of 240 h with 24 +/- 2 mm inhibition zones against Pseudomonas aeruginosa. Furthermore, as a carrier, CS particles significantly improved the compatibility of the antibiotics even at high particle concentrations of 1000 g/mL with a minimum of 71 +/- 7% fibroblast cell viability. In summary, the sustainable delivery of antibiotics and long-term treatment of bacterial keratitis were shown to be afforded by the design of tunable degradation ability of CS particles with improved biocompatibility for the encapsulated drugs.
The Use of Low-Quality Cotton-Derived Cellulose Films as Templates for In Situ Conductive Polymer Synthesis as Promising Biomaterials in Biomedical Applications
(Wiley-V C H Verlag Gmbh, 2025) Demirci, Şahin; Şahiner, Mehtap; Rumi, Shaida S.; Sağbaş Suner, Selin; Abidi, Noureddine; Şahiner, Nurettin
Here, the use of cellulose films (CFs) produced from low-quality cotton is reported as a template for in situ synthesis of well-known conductive polymers, e.g., polyaniline (PANI) and polypyrrole (PPY) via oxidative polymerization. Three successive monomer loading/polymerization cycles of aniline (ANI) and pyrrole (PY) within CFs as PANI@CF or PPY@CF are carried out to increase the amount of conductive polymer content. The contact angle (CA) for three times ANI and PPY loaded and polymerized CFs as 3PANI@CF and 3PPY@CF are determined as 26.3 +/- 2.8 and 42.3 +/- 0.6 degrees, respectively. As the electrical conductivity is increased with increased number of conductive polymer synthesis within CF, the higher conductivity values, 3x10-4 +/- 8.1x10-5 S.cm-1 and 2.1x10-3 +/- 5.8x10-4 S.cm-1, respectively are measured for 3PANI@CF and 3PPY@CF composites. It is found that PANI@CF composites are hemolytic, whereas PPY@CF composites are not at 1 mg mL-1 concentrations. All PPY@CF composites exhibit better biocompatibility than PANI@CF composites on L929 fibroblast cells with more than 70 +/- 8% viability at 1 mg of CF-based conductive polymer composites. Moreover, MIC and MBC values of 3PPY@CF composites for Escherichia coli (ATCC8739) and Staphylococcus aureus (ATCC6538) are determined as 2.5 and 5.0 mg.mL-1, whereas these values are estimated as 5 and 10 mg.mL-1 for Candida albicans (ATCC10231). Cotton fibers are dissolved in N, N-dimethylacetamide/lithium chloride (DMAc/LiCl) solvent system and converted cellulose solutions to strong, transparent, and flexible films through casting, gelation, regeneration, plasticization, and hot-pressing. The prepared cellulose films (CFs) are used as a template for in situ synthesis of polyaniline (PANI) and polypyrrole (PPY) polymers to attain electroactive cellulose based composites with intriguing biomedical properties. image
Slightly degradable, naturally antibacterial hydrogel matrixes derived from polyvinyl alcohol and linear/branched-polyethyleneimine as a wound dressing material
(Taylor & Francis Inc, 2024) Ari, Betül; Sağbaş Suner, Selin; Şahiner, Mehtap; Demirci, Şahin; Şahiner, Nurettin
PVA:PEI based film gels were prepared at various weight ratios, 10-100% of linear-PEI (L-PEI) and branched-PEI (B-PEI) to PVA as PVA:L-PEI or PVA:B-PEI to demonstrate the effect of PEI types on hydrolytic degradation, blood compatibility, antibacterial properties, and cytotoxicity. The hydrolytic degradation studies, done at similar to skin pH, 5.4 and revealed that PVA:PEI-based film gels, 1:0.1 wt% are degradable with a gravimetric weight losses of16.80 +/- 1.39% and 17.20 +/- 1.21% up to 7 days, and decreased as the wt% of L-PEI and B-PEI were increased in the matrix. The blood compatibility assays done through hemolysis and blood clotting tests disclosed only PVA:B-PEI film gels at 1.0 mg/mL concentration were found blood compatible. The antimicrobial studies revealed that regardless of the types and weight ratio of L-PEI or B-PEI, all PVA:L-PEI and PVA:B-PEI based film gels possess a potent antibacterial activity against Pseudomonas aeruginosa, a gram-negative bacteria and Staphylococcus aureus, a gram-positive bacteria. Moreover, the cytotoxicity test results examined on the L929 cell line uncovered that only PVA:L-PEI and PVA:B-PEI even at very low concentrations of L-PEI or B-PEI, for example, PVA:L-PEI and PVA:B-PEI at 1:0.1 weight ratio film gel at 10 mg/mL show toxic effect, for example <50% cell viability suggesting lesser concentration use in biomedical applications.
Synthesis and Characterization of a New Cryogel Matrix for Covalent Immobilization of Catalase
(MDPI, 2022) Altunbaş, Canan; Aslan, Ahmet; Kusat, Kevser; Şahiner, Mehtap; Akgöl, Sinan; Şahiner, Nurettin
The advantages of cryogels for enzyme immobilization applications include their mechanical and chemical robustness, ease of production, superior porosity, and low cost. Currently, many researchers are exploring porous material-based systems for enzyme immobilization that are more efficient and economically viable. Here, poly(2-Hydroxyethyl methacrylate-co-allyl glycidyl ether) (p(HEMA-co-AGE)) cryogel matrices were synthesized via the free radical cryopolymerization method to be employed as the support material. For the immobilization of the catalase enzyme onto the p(HEMA-co-AGE) cryogel matrix (catalase@p(HEMA-co-AGE), the best possible reaction conditions were determined by altering parameters such as pH, catalase initial concentration, and flow rate. The maximum catalase immobilization amount onto the p(HEMA-co-AGE) cryogel was found to be 48 mg/g cryogel. To determine the advantages of the cryogel matrix, e.g., the stability and reusability of the cryogel matrix, the adsorption-desorption cycles for the catalase enzyme were repeated five times using the same cryogel matrix. At the end of the reusability tests, it was found that the cryogel was very stable and maintained its adsorption capacity with the recovery ratio of 93.8 +/- 1.2%. Therefore, the p(HEMA-co-AGE) cryogel matrix affords repeated useability, e.g., up to five times, without decreasing its catalase binding capacities significantly and has promising potential for many industrial applications. Cryogels offer clear distinctive advantages over common materials, e.g., micro/nano particles, hydrogels, films, and composites for these applications. At present, many researchers are working on the design of more effective and economically feasible, porous material-based systems for enzyme immobilization
From a plant secretion to the promising bone grafts: Cryogels of silicon-integrated quince seed mucilage by microwave-assisted sol-gel reaction
(Elsevier B.V., 2021) Yılmaz, Hilal Deniz; Cengiz, Uğur; Arslan, Yavuz Emre; Kıran, Fadime; Ceylan, Ahmet
Design and fabrication of biologically active cryogels using novel biopolymer(s) are still of great importance at regenerating bone defects such as traumatic bone injuries, maxillofacial surgery, osteomyelitis, and osteoporosis. Nowadays, plant mucilage, an herbal biomaterial, has been drawn attention by scientists due to their marvelous potential to fabricate 3-dimensional (3D) physical constructs for the field of regenerative medicine. Herein, a 3D cryogel from silicon-integrated quince seed mucilage (QSM) is constructed using microwave-assisted sol–gel reaction, characterized in-depth by attenuated total reflectance Fourier transform-infrared spectroscopy (ATR-FTIR), solid-state silicon cross-polarization magic-angle nuclear magnetic resonance (29Si-CP-MAS NMR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), micro-mechanical testing, porosity, and swelling tests, contact angle measurements, Brunauer-Emmet-Teller and Barret-Joyner-Halenda (BET-BJH) analysis, enzymatic biodegradation test, and field emission-scanning electron microscopy-energy dispersive X-ray spectroscopy (FE-SEM-EDX) mapping. The osteobiologic capacity of the cryogels is determined using human adipose-derived mesenchymal stem cells (hAMSCs) under in vitro conditions. Osteogenic differentiation of hAMSCs on both QSM and silica-modified QSM (Si-QSM) cryogels is analyzed by histochemistry, immunohistochemistry, and quantitative-real time (q-RT) PCR techniques. The results obtained from in vitro experiments demonstrate that the upregulation of osteogenesis-related genes in Si-QSM cryogels presents a stronger and earlier development over QSM cryogels throughout the culture period, which in turn reveals the great potential of this novel Si-incorporated QSM cryogels for bone tissue engineering applications.
A nano-composite based regenerative neuro biosensor sensitive to Parkinsonism-associated protein DJ-1/Park7 in cerebrospinal fluid and saliva
(Elsevier B.V., 2021) Sonuç Karaboğa, Münteha Nur; Sezgintürk, Mustafa Kemal
In this study, we developed an electrochemical-based single-use neurobiosensor based on multiwalled carbon nanotube (MWCNT)-gold nanoparticle (AuNP) nanocomposite doped, 11-amino-1-undecanethiol (11-AUT)-modified polyethylene terephthalate coated indium tin oxide (ITO-PET) electrodes. This electrode was used for the sensitive determination of DJ-1, a protein responsible for mitochondrial dysfunction in Parkinson's disease (PD) with the task of eliminating oxidative stress. The design strategy and analytical studies for the neurobiosensor were monitored with electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and single frequency impedance (SFI) techniques. The selective determination range for DJ-1 of the developed neurobiosensor system is 4.7–4700 fg mL−1 in accordance with the charge transfer resistance (Rct) associated with a limit of detection of 0.5 fg mL−1. Since changes in the expression of DJ-1 protein is particularly important in cerebrospinal fluid (CSF) and saliva, the ability of the developed neurobiosensor system to detect the DJ-1 protein in these media was tested by the standard addition method. The statistical results show that the biosensor decorated with MWCNT-AuNP-AUT may be recommended for the selective determination of DJ-1 protein.
Ultrasensitive detection of interleukin 1? using 3-phosphonopropionic acid modified FTO surface as an effective platform for disposable biosensor fabrication
(Elsevier B.V., 2021) Aydın, Elif Burcu; Sezgintürk, Mustafa Kemal
In this study, we utilized a carboxyalkylphosphonic acid covered fluorine doped tin oxide (FTO) as an electrode material for fabrication of Interleukin 1α (IL-1α) immunosensor. For this aim, anti-IL-1α antibodies were attached on the 3-phosphonopropionic acid (PHP) modified FTO surface covalently. Electrochemical (electrochemical impedance spectroscopy and cyclic voltammetry) and morphological (scanning electron microscopy and atomic force microscopy) characterizations were performed to monitor the successful fabrication of immunoelectrodes. After incubation of anti-IL-1α antibody immobilized FTO electrodes in IL-1α antigen solutions, increases were seen in impedimetric responses. IL-1α antigen was determined in a linear detection range from 0.02 to 2 pg/mL by EIS. The detection limit of the suggested immunosensor was 6 fg/mL. The applicability of the designed biosensor was tested by using human serum and saliva samples and acceptable results were obtained. In addition, high sensitivity, good specificity, low detection limit made the proposed immunosensor a potential technique for IL-1α antigen determination in routine clinical analysis.
An impedimetric biosensor system based on disposable graphite paper electrodes: Detection of ST2 as a potential biomarker for cardiovascular disease in human serum
(Elsevier B.V., 2021) Demirbakan, Burcak; Sezgintürk, Mustafa Kemal
In present study, we developed a highly sensitive, electrochemical immunosensor based on fullerene C60-modified disposable graphite paper (GP) electrode for determination of Suppression of Tumorigenicity 2 (ST2) in human serum. The synthesis of the ST2 immunosensor was monitored with electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) techniques and single frequency impedance (SFI) technique which is utilized for the specific interaction between anti-ST2 and ST2 antigen. Moreover, the morphological alteration of each GP surface was examined by scanning electron microscopy (SEM), SEM-energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). All parameters such as fullerene C60 concentration, antibody concentration and antibody incubation time were optimized. Analytical characteristics such as linear determination range, repeatability, reproducibility, regeneration and surface coverage were determined for the immunosensor. The ST2 electrochemical immunosensor had excellent repeatability, reproducibility and a wide detection range (from 0.1 fg mL−1 to 100 fg mL−1). The proposed immunosensor also had low limit of detection (LOD) and limit of quantification (LOQ) values of 0.124 fg mL−1 and 0.414 fg mL−1, respectively. The proposed immunosensor was applied to real samples to test applicability in clinical practice.
Advances in immunosensor technology
(Academic Press Inc., 2021) Aydın, Muhammet; Aydın, Elif Burcu; Sezgintürk, Mustafa Kemal
In recent years, advances in immunosensor device fabrication have significantly expanded the use of this technology in a broad range of applications including clinical diagnosis, food analysis, quality control, environmental studies and industrial monitoring. The most important aspect in fabrication is to obtain a design that provides a low detection limit. The utilization of nanomaterials as a label, catalyst and biosensing transducer is, perhaps, the most popular approach in ultrasensitive devices. This chapter reviews recent advances in immunosensor fabrication and summarizes the most recent studies. Strategies employed to significantly improve sensitivity and specificity of immunosensor technology and the advantages and limitations thereof are explored.
Synthesis, characterization, and in vitro drug release properties of AuNPs/p(AETAC-co-VI)/Q nanocomposite hydrogels
(Springer Science and Business Media Deutschland GmbH, 2021) Durmuş, Seçil; Yılmaz, Betül; Kıvanç, Mehmet Rıza; Önder, Alper; Ilgın, Pınar; Özay, Hava; Özay, Özgür
In this study, the cationic monomer [2-(acryloyloxy)ethyl]trimethylammonium chloride solution (AETAC) and vinyl imidazole (VI) were used with the free radical polymerization technique, which is a simple and rapid synthesis method, to synthesize p(AETAC-co-VI) hydrogels. To increase the density of cationic charge on the hydrogel, it underwent the protonation process with HCl. The obtained p(AETAC-co-VI)/Q hydrogel was modified with Au nanoparticles to increase bactericidal effect to obtain the AuNPs/p(AETAC-co-VI)/Q nanocomposite hydrogel. The morphology and chemical structure of the hydrogels were characterized with SEM and FTIR. Additionally, the swelling capabilities were tested in different pH media. XRD and TEM confirmed the formation of the nanocomposite hydrogel. The antibacterial activity of the hydrogels was tested against E. coli and S. aureus, and controlled release implementations were completed with sodium diclofenac (NaDc) drug. The NaDc drug release profiles of the hydrogels were researched using the Korsmeyer–Peppas model at 37 °C in different simulated buffer (pH 6.0, 7.2, and 8.0) solutions. It was found that both the hydrogel and nanocomposite hydrogel followed non-Fickian diffusion mechanisms as free release mechanism. Here, the maximum drug release efficacy was found to be 97%, and drug release was more rapid in basic media when release media were compared. The AuNPs/p(AETAC-co-VI)/Q nanocomposite hydrogels produced in this study with advanced antibacterial features were suitable for recommendation as good carriers for in vitro release of NaDc drugs in areas like the biomedical and pharmaceutical industries.
Decellularized spinal cord meninges extracellular matrix hydrogel that supports neurogenic differentiation and vascular structure formation
(John Wiley and Sons Ltd, 2021) Özüdoğru, Eren; Işık, Melis; Eylem, Cemil Can; Nemutlu, Emirhan; Arslan, Yavuz Emre; Derkus, Burak
Decellularization of extracellular matrices offers an alternative source of regenerative biomaterials that preserve biochemical structure and matrix components of native tissues. In this study, decellularized bovine spinal cord meninges (dSCM)-derived extracellular matrix hydrogel (MeninGEL) is fabricated by employing a protocol that involves physical, chemical, and enzymatic processing of spinal meninges tissue and preserves the biochemical structure of meninges. The success of decellularization is characterized by measuring the contents of residual DNA, glycosaminoglycans, and hydroxyproline, while a proteomics analysis is applied to reveal the composition of MeninGEL. Frequency and temperature sweep rheometry show that dSCM forms self-supporting hydrogel at physiological temperature. The MeninGEL possesses excellent cytocompatibility. Moreover, it is evidenced with immuno/histochemistry and gene expression studies that the hydrogel induces growth-factor free differentiation of human mesenchymal stem cells into neural-lineage cells. Furthermore, MeninGEL instructs human umbilical vein endothelial cells to form vascular branching. With its innate bioactivity and low batch-to-batch variation property, the MeninGEL has the potential to be an off-the-shelf product in nerve tissue regeneration and restoration.
Ultrasensitive and Selective Impedimetric Determination of Prostate Specific Membrane Antigen Based on Di-Succinimide Functionalized Polythiophene Covered Cost-Effective Indium Tin Oxide
(John Wiley and Sons Inc, 2021) Aydın, Elif Burcu; Aydın, Muhammet; Sezgintürk, Mustafa Kemal
A new and ultrasensitive impedimetric biosensor fabricated by using conjugated di-succinimide substituted polythiophene (P(ThidiSuc)) polymer modified indium tin oxide electrode is developed for the first time to detect the prostate specific membrane antigen (PSMA). The polymer P(Thi-diSuc) is synthesized by using a simple way and used in the fabrication of the proposed biosensor. The synthesized polymer contains di-succinimide groups, which offers covalent immobilization of PSMA specific antibodies. The developed strategy shortens the biosensor fabrication steps, because these active groups bind covalently to the amino ends of PSMA specific antibodies and this reaction does not require any crosslinking agent. Various characterization studies like impedimetric and voltammetric measurements, and morphological analyses are utilized to confirm the successful development of the biosensor. Under optimum conditions, the biosensing ability of the PSMA determination has a wide linear determination range from 0.015 to 14.4 pg mL−1, as well as a low limit of detection of 6.4 fg mL−1 and a high sensitivity of 1.36 kohm pg−1 mL cm−2. Furthermore, the proposed biosensor is able to measure the PSMA antigen in real human serums, which offers that it is a simple, low-cost, and sensitive tool with excellent potential for application in the quantification of PSMA.
Electrochemical Immunosensor for Detection of CCR4 Cancer Biomarker in Human Serum: An Alternative Strategy for Modification of Disposable ITO Electrode
(Wiley-VCH Verlag, 2021) Aydın, Elif Burcu; Aydın, Muhammet; Sezgintürk, Mustafa Kemal
Herein, a new strategy for the fabrication of a sensitive immunosensor capable of determination of CC Chemokine receptor 4 (CCR4) in complex serum samples is developed through the polymer modification on the disposable indium tin oxide electrode. Anti-CCR4 antibodies, which are utilized as sensing biomolecules, are covalently attached on the succinimide groups of polypyrrole polymer (PPyr-CSsg). The constructed immunosensor illustrates promising performances for the quantification of CCR4 antigen, with a linear detection range of 0.024–12 pg mL−1 and a low detection limit of 7.3 fg mL−1, calculated at a signal-to-noise ratio of 3. In addition, the impedimetric immunosensor displays a very successful analytical performance in terms of sensitivity, selectivity, repeatability, reproducibility, and long-term stability as well as successful applicability for the accurate quantification of CCR4 in human serum samples. The constructed immunosensor is successfully used for quantification of CCR4 antigen in human serums. In addition, the immunosensor displays only 27.54% loss in its initial signal after nine weeks storage at 4 °C. Moreover, the fabricated immunosensor is economical, highly sensitive, and selective for CCR4 antigen detection, and suitable for potential application in clinical diagnosis.
Development and characterization of skin substitutes from electrospun polycaprolactone/silk fibroin
(SAGE Publications Ltd, 2024) Yıldız, Gülşah; Arslan, Yavuz Emre; Derkus, Burak; Sezgin, Billur; Menceloglu, Yusuf Ziya; Bayar, Gürkan Raşit
Tissue-engineered skin substitutes have great potential to treat chronic wounds and high-degree burns. Existing solutions, such as Integra Dermal Template, are extensively used for skin defects. However, these templates are still lacking in terms of recreating the functionality of the native tissue and providing scarless healing. In this study, polycaprolactone/silk fibroin (PCL/SF)-based nanofibers with varying blends were fabricated and characterized to develop a novel skin substitute. Morphological analysis showed that the nanofiber distribution of each sample was homogenous without showing any beads. In terms of mechanical properties, all the samples other than SF showed sufficient mechanical strength. It was observed that adding a specific amount of SF into the PCL nanofiber improves the tensile strength of the samples due to the introduction of intermolecular interactions from the functional groups of SF. In addition, incorporating SF into PCL improved Young’s modulus of the PCL nanofibers since SF provides stiffness and structural integrity to the overall structure. Water contact angle analysis was performed as the hydrophilicity of a biomaterial is a significant factor in cell functionality. Each sample had a contact angle between 33° and 48°, indicating the adequate hydrophilicity of nanofibers for advanced cell proliferation other than PCL. Cell proliferation and viability studies were conducted with the seeding of primary human keratinocytes on the samples. It was examined that scaffolds containing blends of PCL and SF resulted in higher cell proliferation and viability after 7 days compared to pure PCL and SF nanofibers.
Organic-inorganic biohybrid films from wool-keratin/jellyfish-collagen/silica/boron via sol-gel reactions for soft tissue engineering applications
(IOP Publishing, 2024) Yıldız, Safiye Nur; Sezgin Arslan, Tugba; Arslan, Yavuz Emre
Therapeutic angiogenesis is pivotal in creating effective tissue-engineered constructs that deliver nutrients and oxygen to surrounding cells. Hence, biomaterials that promote angiogenesis can enhance the efficacy of various medical treatments, encompassing tissue engineering, wound healing, and drug delivery systems. Considering these, we propose a rapid method for producing composite silicon-boron-wool keratin/jellyfish collagen (Si-B-WK/JFC) inorganic-organic biohybrid films using sol-gel reactions. In this approach, reactive tetraethyl orthosilicate and boric acid (pKa ⩾ 9.24) were used as silicon and boron sources, respectively, and a solid-state gel was formed through the condensation reaction of these reactive groups with the keratin/collagen mixture. Once the resulting gel was thoroughly suspended in water, the films were prepared by a casting/solvent evaporation methodology. The fabricated hybrid films were characterized structurally and mechanically. In addition, angiogenic characteristics were determined by the in ovo chick chorioallantoic membrane assay, which revealed an increased vascular network within the Si-B-WK/JFC biohybrid films. In conclusion, it is believed that Si-B-WK/JFC biohybrid films with mechanical and pro-angiogenic properties have the potential to be possessed in soft tissue engineering applications, especially wound healing.
Ultrasensitive detection of NSE employing a novel electrochemical immunosensor based on a conjugated copolymer
(Royal Society of Chemistry, 2024) Aydın, Muhammet; Aydın, Elif Burcu; Sezgintürk, Mustafa Kemal
In the current study a simple and highly specific label-free impedimetric neuron specific enolase (NSE) immunosensor based on a copolymer matrix-coated disposable electrode was designed and tested. The copolymer matrix was prepared using a very conductive EDOT monomer and semi-conductive thiophene-bearing epoxy groups (ThEp), and the combination of the two monomers enhanced the conductivity and protein loading capacity of the electrode surface. The P(ThEp-co-EDOT) copolymer matrix was prepared via a drop-casting process and anti-NSE recognition biomolecules were immobilized directly on the epoxy groups of the copolymer. After the coupling of NSE molecules on the P(ThEp-co-EDOT) copolymer matrix-coated electrode surface, the charge transfer resistance (Rct) of the biosensor changed dramatically. These changes in Rct were proportional to the NSE molecule amounts captured by anti-NSE molecules. Under optimized experimental conditions, the increment in the Rct value was proportional to the NSE concentration over a range of 0.01 to 25 pg mL−1 with a detection limit (LOD) of 2.98 × 10−3 pg mL−1. This copolymer-coated electrode provided a lower LOD than the other biosensors. In addition, the suggested electrochemical immuno-platform showed good selectivity, superior reproducibility, long-term stability, and high recovery of NSE in real serum (95.64-102.20%) and saliva (95.28-105.35%) samples. These results showed that the present system had great potential for electrochemical biosensing applications.
Synthesis and characterization of poly(Maltodextrin) microgel from maltodextrin as drug delivery system
(Elsevier B.V., 2024) Şahiner, Mehtap; Güngör, Buket; Sılan, Coşkun; Demirci, Şahin; Erdoğan, Hakika; Ayyala, Ramesh S.; Şahiner, Nurettin
Microgels of maltodextrin (MDex) as poly(maltodextrin) (p(MDex)) were prepared by reverse-micelle crosslinking technique at various crosslinking ratios, 25, 50, and 100% based on the repeating unit of MDex using divinylsulfone (DVS) as crosslinker and were designated as p(MDex)-1, p(MDex)-2, and p(MDex)-3 respectively. The prepared p(MDex) microgels were blood compatible with <2% hemolysis and > 80%blood clotting index values at 1.0 mg/mL concentration. Also, p(MDex) microgels were found as biocompatible with >90% cell viability against L929 fibroblast cells at 1.0 mg/mL concentrations. Furthermore, p(MDex)-3 microgels were modified with ethylenediamine (EDA) and pentaethylenehexamine (PEHA) to generate new amine groups on microgels surface to obtain p(MDex)-EDA and p(MDex)-PEHA, respectively to render new surface functionality and features. The drug delivery potentials of p(MDex)-3, p(MDex)-EDA, and p(MDex)-PEHA microgels were tested employing amoxicillin (Amox) for loading and release studies at pH 7.4 and 37 degrees C. Higher drug loading amount, loading content%, and encapsulation efficiency% values were attained for p(MDex)-PEHA microgels with 112.5 +/- 9.9 mg/g, 12.8 +/- 1.1%, and 63.4 +/- 4.1%, respectively. The Amox-loaded p(MDex)-3, p(MDex)-EDA, and p(MDex)-PEHA microgels released 90.8 +/- 0.9, 86.2 +/- 10.8, and 87.2 +/- 9.6% of the loaded Amox at pH 7.4 PBS in 125 h. Controlled and extended drug delivery system at the therapeutic window is of paramount significance in treatment of various diseases. P(MDex)-PEHA microgels revealed almost a linear Amox release profile for up to 28 h. The Amox release from the p(MDex) microgels was fitted with the Korsmeyer-Peppas model with n values <0.5.

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