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Öğe Aptamer decorated PDA@magnetic silica microparticles for bacteria purification(Springer Wien, 2024) Kavruk, Murat; Babaie, Zahra; Kibar, Gunes; Cetin, Barbaros; Yesilkaya, Hasan; Amrani, Yassine; Dursun, Ali DoganOne significant constraint in the advancement of biosensors is the signal-to-noise ratio, which is adversely affected by the presence of interfering factors such as blood in the sample matrix. In the present investigation, a specific aptamer binding was chosen for its affinity, while exhibiting no binding affinity towards non-target bacterial cells. This selective binding property was leveraged to facilitate the production of magnetic microparticles decorated with aptamers. A novel assay was developed to effectively isolate S. pneumoniae from PBS or directly from blood samples using an aptamer with an affinity constant of 72.8 nM. The capture experiments demonstrated efficiencies up to 87% and 66% are achievable for isolating spiked S. pneumoniae in 1 mL PBS and blood samples, respectively.Öğe Assessment of Anticancer Effects of Aloe vera on 3D Liver Tumor Spheroids in a Microfluidic Platform(Wiley, 2025) Tevlek, Atakan; Kibar, Gunes; Cetin, BarbarosThe search for effective anticancer therapies has increasingly focused on natural compounds like Aloe vera, renowned for its therapeutic properties. This study investigates the anticancer properties of Aloe vera on 3D liver tumor spheroids via a PDMS-based microfluidic device, providing a more physiologically realistic model compared to traditional 2D cultures. HepG2 cells were cultivated to generate 3D spheroids on-chip, thereafter subjected to different concentrations of Aloe vera and the chemotherapeutic drug Doxorubicin to evaluate cytotoxic effects. The microfluidic system, validated by COMSOL simulations, facilitated continuous perfusion and real-time assessment of cell viability over a duration of 10 days. The results indicated that Aloe vera markedly diminished cell viability by triggering apoptosis at concentrations over 12.5 mg/mL. IC50 values were determined at 72 h: 25 +/- 0.10 mg/mL for Aloe vera and 5.47 +/- 0.03 mu g/mL for Doxorubicin in 2D cultures, but in 3D cultures, the IC50 values were 31.25 +/- 0.14 mg/mL for Aloe vera and 8.33 +/- 0.05 mu g/mL for Doxorubicin. This study underscores the promise of Aloe vera as a natural anticancer agent and illustrates the efficacy of microfluidic platforms for enhanced drug screening and customized medicine applications.Öğe Effect of Crosslinking Agent on Mesoporous Spherical POSS Hybrid Particles: Synthesis, Characterization and Thermal Stability(Springer, 2023) Kibar, GunesThis work reports the synthesis of two novel polyhedral oligomeric silsesquioxane (POSS) hybrid particles by investigating the effects of different crosslinking agents on morphology, porosity, chemical structure, crystalline properties, and thermal behavior of the resultant products. The hydrophilic glycerol dimethacrylate and hydrophobic ethylene glycol dimethacrylate (EGDMA) were used as co-monomer and crosslinking agents to obtain novel poly(POSS-co-GDMA) and poly(POSS-co-EGDMA) hybrid spherical microparticles by step-wise Pickering-like seeded polymerization. The crosslinking agent played a key role in specific surface area (SSA), average pore size, and pore volume, characterized by Brunauer-Emmett-Teller and Barrett-Joyner-Halenda analysis. When poly(POSS-co-GDMA) possess 88.0m(2)/g SSA, poly(POSS-co-EGDMA) has 3.5m(2)/g. Both particles exhibit a homogenous spherical shape in the polydisperse form and hybrid organosilica structure defined by scanning electron microscope, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy. The hybrid particles showed an amorphous silica composite character with thermal resistance up to 420 ?, determined by X-ray diffraction and thermogravimetric analysis. The mesoporous hybrid POSS particles could have great potential for many advanced material applications.(GRAPHICS)Öğe Evaluation of drug carrier hepatotoxicity using primary cell culture models(Elsevier, 2023) Kibar, Gunes; Dutta, Subhadeep; Rege, Kaushal; Usta, O. BerkThis study aims to establish a primary rat hepatocyte culture model to evaluate dose-dependent hepatotoxic effects of drug carriers (lipopolymer nanoparticles; LPNs) temporal. Primary rat hepatocyte cell cultures were used to determine half-maximal Inhibition Concen-trations (IC50) of the drug-carrier library. Drug-carrier library, at concentrations <50 mu g/mL, is benign to primary rat hepatocytes as determined using albumin and urea secretions. Albumin, as a hepatic biomarker, exhibited a more sensitive and faster outcome, compared to urea, for the determination of the IC50 value of LPNs. Temporal measurements of hepatic biomarkers including urea and albumin, and rigorous physi-cochemical (hydrodynamic diameter, surface charge, etc.) characterization, should be combined to evaluate the hepatotoxicity of drug carrier libraries in screens.(c) 2023 Published by Elsevier Inc.Öğe Expanding the role of exosomes in drug, biomolecule, and nanoparticle delivery(Pergamon-Elsevier Science Ltd, 2025) Saka, Ongun Mehmet; Dora, Devrim Demir; Kibar, Gunes; Tevlek, AtakanExosomes are nanoscale extracellular vesicles released by diverse cell types, serving essential functions in intercellular communication and physiological processes. These vesicles have garnered considerable interest in recent years for their potential as drug delivery systems, attributed to their natural origin, minimal immunogenicity, high biocompatibility, and capacity to traverse biological barriers, including the blood-brain barrier. Exosomes can be obtained from diverse biological fluids, rendering them accessible and versatile vehicles for therapeutic medicines. This study emphasizes the burgeoning significance of exosomes in drug administration, concentrating on their benefits, including improved stability, target selectivity, and the capacity to encapsulate various biomolecules, such as proteins, nucleic acids, and small molecules. Notwithstanding their potential applications, other problems remain, including as effective drug loading, industrial scalability, and the standardization of isolation methodologies. Overcoming these hurdles via new research is essential for fully harnessing the promise of exosomes in therapeutic applications, especially in the treatment of intricate diseases like cancer and neurological disorders.Öğe Gold-Nanoparticle Decorated Monosized Magnetic Polymer Based Catalyst: Reduction of 4-Nitrophenol(Springer, 2018) Kibar, Gunes; Tuncel, AliThe objective of this study was to fabricate a multifunctional catalyst for removal of environmental pollutants. By this aim, poly(mono-2-(methacryloyloxy)ethyl succinate-co-glycerol dimethacrylate) poly(MMES-co-GDMA) monosized microbeads with carboxyl functionality were synthesized 5 mu m in diameter. Iron oxide nanoparticles were attached onto the polymeric microbeads to obtain superparamagnetic properties for easily collecting them from the reaction medium by using natural magnet. The magnetic polymer microbeads were decorated with gold nanoparticles ca. 15nm in size. The magnetic-monodisperse catalyst carrying gold nanoparticles exhibited several advantages with respect to similar plasmonic catalysts in the form of nanoparticles, like higher aggregation resistance, easier recovery from the reaction medium with natural magnets and reuse of catalyst without leaching gold nanoparticles. The magnetic gold catalyst was characterized by scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and X-ray diffraction spectrophotometry (XRD). This newly designed catalyst was used to degrade a toxic organic substance, 4-nitrophenol (4-NP) in an aqueous medium. The degradation process of 4-NP to 4-aminophenol (4-AP) was monitored by a UV-Visible spectrophotometer. The effects of reaction conditions, catalyst and organic pollutant concentrations and temperature, on the plasmonic catalytic activity were determined. The results of repetitive trials were successful with high catalytic activity for the reduction of 4-NP to 4-AP form in several minutes by using and reusing the synthesized catalyst.Öğe In-situ growth of Ag on mussel-inspired polydopamine@poly(M-POSS) hybrid nanoparticles and their catalytic activity(Elsevier Sci Ltd, 2019) Kibar, Gunes; Dinc, Dilek Sura OzdenPolyhedral oligomeric silsesquioxane (POSS) nanoparticles have gain much attention due to their organic and inorganic hybrid structure that combine with metal nanoparticles to improve their functional properties for utilize in potential application areas. In this study, we first time present a green route for in-situ growth of silver on the surface of POSS based support particles by using mussel inspired polydopamine (PDA) coating. The POSS based nanocomposite support were synthesized by free radical mechanism in one-step emulsion polymerization of methacryl(M)-POSS monomer. Smooth spherical shape in size range of 200 nm-400 nm poly(M-POSS) hybrid latex particles were covered by the functional amine and catechol groups of PDA. Silver layer were growth on PDA@poly(M-POSS) nanocomposite template. The novel multi-functional Ag@PDA@poly(M-POSS) nanocomposite particles were fully characterized by SEM, EDAX, XRD and FTIR analysis. The catalytic activity of the particles was checked by pseudo-first order kinetic reaction of nitrophenol compound, which is highly toxic for environment. The catalytic reaction performance was discussed by varying the catalyst amount and concentration of 4-nitrophenol. Compare to similar catalysts, results showed that Ag@PDA@poly(M-POSS) nanocomposite particles exhibited excellent catalytic activity for the rapid degradation of 4-NP.Öğe Microfluidic rapid isolation and electrochemical detection of S. pneumonia via aptamer-decorated surfaces(Elsevier, 2025) Babaie, Zahra; Kibar, Gunes; Yesilkaya, Hasan; Amrani, Yassine; Dogan, Soner; Tuna, Bilge G.; Ozalp, Veli C.; Cetin, BarbarosBackground: S. pneumoniae is widely recognized as a leading cause of respiratory infections worldwide, often resulting in high mortality rates. However, the advent of microfluidic technologies has brought significant advancements, including the simplified, sensitive, cost-effective, and rapid approach to pneumococcal bacteremia detection. In this study, a microfluidic magnetic platform is presented for rapid isolation, and an electrode array is utilized for the electrochemical detection of S. pneumoniae. Aptamer-decorated surfaces were employed for both isolation and detection. For isolation, silica magnetic microparticles were synthesized and decorated with aptamer. Results: Isolation performance was assessed for phosphate-buffered saline (PBS) and blood samples for different concentrations of S. pneumoniae. Electrical impedance spectroscopy (EIS) with fabricated gold interdigitated electrodes (IDEs) decorated with aptamer was implemented for the detection of S. pneumoniae at different bacteria concentrations. The microfluidic platform performed bacteria isolation at comparable isolation efficiency with batch systems but at a much faster rate (isolation took about a minute, and the aptamer-decorated electrode array exhibited a limit of detection (LOD) at 962 CFU/mL and linear range between 104 and 107CFU/mL. Significance: Our method represents a significant advancement compared to previous reports. Our microfluidic platform can efficiently isolate 60 mu L of the bacteria sample within about one minute. The entire process takes about two minutes including the detection step. Furthermore, our method achieves a notable improvement in the detection limit for S. pneumoniae compared to conventional ELISA and magnetic microfluidics ELISA.Öğe Microfluidic vs. batch synthesis of fluorescent poly(GMA-co-EGDMA) micro/nanoparticles for biomedical applications(Springernature, 2024) Kilincli, Betul; Cinar, Ayse Duru; Cetin, Barbaros; Kibar, GunesFluorescent particles play a crucial role in nanomedicine and biological applications such as imaging, diagnostic tools, drug delivery, biosensing, multimodal imaging, and theranostics. This report presents a novel synthesis method and comparative study for synthesizing fluorescent particles in microfluidic continuous and batch-type reactors. Glycidyl methacrylate (GMA) and ethylene glycol dimethyl acrylate (EGDMA) are well-known monomers for synthesizing functional particles for biomedical applications. Several methods exist to obtain fluorescent poly(GMA-co-EGDMA) (p(GMA-EGDMA))particles through various polymerization techniques. Unlike existing methods, we developed a green approach for synthesizing fluorescent p(GMA-EGDMA) particles via UV-initiated one-step emulsion polymerization by comparing microfluidic and batch synthesis. Moreover, as a fluorescent dye, fluorescein isothiocyanate (FITC) was directly incorporated with p(GMA-EGDMA) particles at various concentrations to achieve tunable fluorescent functionality. While the batch synthesis resulted in polydisperse fluorescent p(GMA-EGDMA)microparticles with spherical shapes ranging from 25 mu m to 1.0 mu m in size, the microfluidic synthesis produced nonspherical nanoparticles. Fluorescent FITC@p(GMA-EGDMA) particles were characterized by scanning electron microscope (SEM), fluorescent microscope, and Fourier-transform infrared spectroscopy (FTIR). The synthesized particles have potential for fluorescence imaging applications, specifically bio-detection in array systems.Öğe Multifunctional POSS-based nanoparticles functionalized with silver, SPIONs, and rhamnolipid for antibacterial applications(Elsevier, 2026) Kibar, Gunes; Kafali, Melisa; Ozonuk, Olgu Cagan; Oztas, Merve; Usta, Berk; Ercan, BaturNano-engineered materials, particularly those featuring bio-based surface modifications, are emerging as effective tools in combating bacterial infections. In this study, polyhedral oligomeric silsesquioxane (POSS) nanoparticles were functionalized with silver nanoparticles (Ag), superparamagnetic iron oxide nanoparticles (SPIONs), and the biosurfactant rhamnolipid (RL)-either individually or in combination-to evaluate their antibacterial and antibiofilm activities against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). The modified nanoparticles exhibited sizes ranging from 127 to 227 nm and demonstrated superparamagnetic behavior, offering potential for magnetic targeting. Among the various formulations, the RLcoated, silver- and SPION-decorated POSS nanoparticles (RSMP) exhibited the highest antibacterial efficacy, reducing S. aureus and P. aeruginosa colony growth by approximately 90 % and 66 %, respectively, at a concentration of 0.01 g/L. RSMP nanoparticles also showed strong biofilm inhibition and had the lowest MIC50 values. Notably, these nanoparticles supported the proliferation of human osteoblasts at concentrations up to 0.05 g/L, indicating favorable cytocompatibility. Overall, RSMP nanoparticles present a promising platform for magnetically targetable antibacterial agents, with potential applications in biomedical fields, particularly for managing orthopedic infections.Öğe Novel 3D-Printed Microfluidic Magnetic Platform for Rapid DNA Isolation(Amer Chemical Soc, 2024) Kibar, Gunes; Sariarslan, Busra; Doganay, Serkan; Yildiz, Gokay; Usta, O. Berk; Cetin, BarbarosThis study presents a novel miniaturized device as a 3D-printed microfluidic magnetic platform specifically designed to manipulate magnetic microparticles in a microfluidic chip for rapid deoxyribonucleic acid (DNA) isolation. The novel design enables the movement of the magnetic particles in the same or opposite directions with the flow or suspends them in continuous flow. A computational model was developed to assess the effectiveness of the magnetic manipulation of the particles. Superparamagnetic monodisperse silica particles synthesized in-house are utilized for the isolation of fish sperm DNA and human placenta DNA. It was demonstrated that the proposed platform can perform DNA isolation within 10 min with an isolation efficiency of 50% at optimum operating conditions.Öğe One-pot synthesis of organic-inorganic hybrid polyhedral oligomeric silsesquioxane microparticles in a double-zone temperature controlled microfluidic reactor(Wiley, 2019) Kibar, Gunes; Caliskan, Umutcan; Erdem, E. Yegan; Cetin, BarbarosPolyhedral oligomeric silsesquioxane (POSS) particles are one of the smallest organosilica nano-cage structures with high multifunctionality that show both organic and inorganic properties. Until now poly(POSS) structures have been synthesized from beginning with a methacryl-POSS monomer in free-radical mechanism with batch-wise methods that use sacrificial templates or additional multisteps. This study introduces a novel one-pot synthesis inside a continuous flow, double temperature zone microfluidic reactor where the methodology is based on dispersion polymerization. As a result, spherical monodisperse POSS microparticles were obtained and characterized to determine their morphology, surface chemical structure, and thermal behavior by SEM, FTIR, and TGA, respectively. These results were also compared and reported with the outcomes of batch-wise synthesis. (c) 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1396-1403Öğe Spherical shape poly(M-POSS) micro/nano hybrid latex particles: One-step synthesis and characterization(Wiley, 2020) Kibar, GunesThis research introduces for the first time a simple one-step synthesis method based on emulsion polymerization to obtain spherical shape poly(Methacryl-Polyoctahedral Silsesquioxanes) poly(M-POSS) micro/nano hybrid latex particles through a free radical mechanism. The polymerization parameters such as the ultrasound source, the amount of surfactant sodium dodecyl sulfate (SDS) and the addition of the cosurfactants SDS/polyvinylpyrrolidone K30 (PVP-K30), and SDS/polyvinyl alcohol (PVA) in emulsion medium were investigated. The morphological, chemical, thermal, and crystalline properties of poly(M-POSS), as a function of these parameters, were analyzed by means of scanning electron microscope, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction, respectively. The ultrasound source was found to have no significant effect on the final properties of the particles. However, the addition of a cosurfactant plays a major role in the distribution and coagulation of the latex particles. The addition of PVA as a cosurfactant significantly decreased the coalescence behavior of the latex particles, whereas the addition of PVP-K30 caused Ostwald ripening effect in over-micron size particles. As a result, the poly(M-POSS) micro/nano particles were obtained in spherical shape in the size range between 0.2 and 20 mu m. They possess both organic and inorganic parts with thermal resistance up to 400 degrees C, which potentially serve as coating or filler additive materials.Öğe Ultrafast Green Synthesis of Superparamagnetic Hybrid Nanoparticle for Advanced Applications(Wiley, 2025) Kibar, GunesThe integration of superparamagnetic iron oxide nanoparticles (SPIONs) into functional hybrid nanostructures remains a challenge, particularly in preserving their magnetic properties within composite frameworks. Herein, we present a rapid and environmentally friendly synthesis strategy for SPION-decorated polyhedral oligomeric silsesquioxane (POSS) nanoparticles. The process involves UV-induced polymerization to form POSS nanoparticles, followed by in situ SPION precipitation, with comprehensive characterization performed via SEM, FTIR, XRD, and VSM analyses. This approach enables the fabrication of hybrid nanoparticles (similar to 160 nm) within 5 min and subsequent SPION decoration in under an hour, ensuring (10 emu/g) superparamagnetic behavior. The developed method is highly scalable, efficient, and compatible with green chemistry principles, making it a promising platform for engineering advanced hybrid nanostructures. These nanoparticles hold significant potential for applications in biomedicine, catalysis, and next-generation material science.
