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Article Catalyst-Free Synthesis of Thiourea-Linked Dumbbell-Shaped POSS for Ultrasensitive Determination of Prilocaine in Human Blood with Computational Insights(Elsevier Inc., 2026) Bilge, S.; Bayraktar, E.N.; Erkmen, C.; Balci, B.; Abofoul, A.; Içli-Özkut, M.I.; Cihaner, A.Although various electrochemical sensors have been reported for the determination of local anesthetic drugs, most existing platforms suffer from limited sensitivity, insufficient surface stability, or inadequate electron-transfer efficiency, particularly when applied to complex biological matrices. Moreover, the potential of hybrid polyhedral oligomeric silsesquioxane (POSS)-based nanostructures combined with metal oxide nanoparticles for improving electroanalytical performance has not yet been thoroughly explored. In this study, a high-sensitivity electrochemical nanosensor was developed for the determination of prilocaine (PC), an amide-type local anesthetic, using a glassy carbon (GC) electrode modified with POSS‑titanium dioxide (TiO2) nanoparticles (Nps). The combination of modifications provided a unique electrode surface by combining the high stability of POSS with the strong adsorption properties of TiO2 Nps, thereby increasing both surface loading and adsorption capacity. To elucidate the structure of the modification combination, 1H and 13C nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopic techniques, as well as Brunauer–Emmett–Teller (BET), X-Ray diffraction (XRD), Electrochemical impedance spectroscopy (EIS), and high-resolution transmission electron microscopy (HRTEM) analysis techniques were used, respectively. The analytical performance of the developed nanosensor was systematically optimized using differential pulse voltammetry (DPV), adsorptive stripping differential pulse voltammetry (AdSDPV), square wave voltammetry (SWV), and adsorptive stripping square wave voltammetry (AdSSWV) techniques. As a result of the optimization studies, the lowest limit of detection (LOD) was 3.66 × 10−8 M with the AdSSWV technique. DFT results corroborated the mechanism, indicating ring-centered electron donation (HOMO) and adsorption-favored N/O regions (MEP). Low LOD values were also recorded with other techniques, demonstrating the method's high sensitivity in analyte detection. In real sample analysis tests, PC recovery value in human blood samples was determined to be 98.69% using the AdSDPV technique. Despite the matrix effect, the nanosensor demonstrated high accuracy and reproducibility. The results indicate that the developed POSS-TiO2 Nps modified GC electrode sensor offers a high-performance, reliable, and good electrochemical detection platform suitable for use in biological and clinical applications. © 2024Article Citation - WoS: 8Citation - Scopus: 8Improvement of Optical Properties and Redox Stability of Poly(3,4-Ethylenedioxythiophene)(Elsevier Sci Ltd, 2018) Ertan, Salih; Cihaner, AtillaIn order to improve the optical properties and redox stability of poly(3,4-ethylenedioxythiophene) (PEDOT) without changing its electrochemical and electrochromic behaviour, it was supported with alkyl-substituted polyhedral oligomeric silsesquioxane (POSS) cage. The corresponding copolymers were obtained electrochemically via potentiostatic or potentiodynamic methods and compared to the parent homopolymers. Electrochemical polymerization of EDOT and POSS containing EDOT called EDOT-POSS in various monomer feed ratios was performed in an electrolyte solution of 0.1 M TBAPF(6) dissolved in a mixture of dichloromethane and acetonitrile (1/3: v/v). Just as PEDOT, the copolymers represented the similar band gap (1.61 eV), redox and electrochromic behaviors. On the other hand, when compared to the parent PEDOT, the presence of POSS cages in the copolymer backbone improved the redox stability and optical properties of PEDOT such as higher percent transmittance change (65% at 621 nm), higher transparency at oxidized state, lower switching time (similar to 1.0 s) and higher coloration efficiency (463 cm(2)/C for 95% switching) as well as higher electrochemical stability (86% of its electroactivity retains after 1750 cycles under ambient conditions).Article Citation - WoS: 11Citation - Scopus: 11Electrochemical and Optical Properties of Substituted Phthalimide Based Monomers and Electrochemical Polymerization of 3,4-Ethylenedioxythiophene Oligomeric Silsesquioxane (poss) Analogue(Elsevier Sci Ltd, 2019) Cakal, Deniz; Ertan, Salih; Cihaner, Atilla; Onal, Ahmet M.A new series of donor-acceptor-donor type trimeric monomers bearing substituted phthalimide units as acceptor units and thiophene and 3,4-ethylenedioxythiophene (EDOT) as donor units was synthesized and characterized. The strength of acceptor units and intramolecular charge transfer between donor and acceptor units were investigated by using electrochemical and optical methods. The main advantage of phthalimide unit over other acceptor units is the ease of its functionalizability. Thus, utilizing this property, a phthalimide derivative (E2P-POSS) bearing polyhedral oligomeric silsesquioxane (POSS) cage was introduced successfully with EDOT and polymerized electrochemically. The corresponding electroactive polymer, PE2P-POSS, has a band gap of 1.72 eV and is an electrochromic polymer: gray when neutralized and eggplant purple when oxidized.Article Citation - WoS: 12Citation - Scopus: 14A Platform To Synthesize a Soluble Poly(3,4-Ethylenedioxythiophene) Analogue(Wiley, 2017) Ertan, Salih; Kaynak, Cevdet; Cihaner, AtillaAlkyl-substituted polyhedral oligomeric silsesquioxane (POSS) cage is combined with 3,4-ethylenedioxythiophene under the same roof. The corresponding monomer called EDOT-POSS is used to get soluble poly(3,4-ethylenedioxythiophene) (PEDOT-POSS) analogue. Both chemically and electrochemically obtained polymers are soluble in common organic solvents like dichloromethane, chloroform, tetrahydrofuran, and so forth. The PEDOT-POSS has somewhat higher band gap (1.71 eV at 618 nm) than its parent PEDOT (1.60 eV at 627 nm) and as expected the PEDOT-POSS exhibits higher optical contrast (74% at 618 nm) and coloration efficiency (582 cm(2)/C for 100% switching), lower switching time (0.9 s), higher electrochemical stability (93% of its electroactivity retains after 5000 cycles under ambient conditions) when compared to the PEDOT. A number of advantages of the PEDOT-POSS over the PEDOT can make it a promising material in the areas of electro-optical applications. (C) 2017 Wiley Periodicals, Inc.Article Citation - WoS: 9Citation - Scopus: 10Polyhedral Oligomeric Silsesquioxanes Appended Conjugated Soluble Polymers Based on Thieno[3,4-C]pyrrole Acceptor Unit(Pergamon-elsevier Science Ltd, 2021) Cakal, Deniz; Cihaner, Atilla; Onal, Ahmet M.A series of new donor-acceptor-donor type fluorescent molecules incorporating thieno[3,4-c]pyrrole-4,6-dione (TPD) as the acceptor unit were synthesized. TPD acceptor unit was modified with polyhedral oligomeric silsesquioxanes (POSS) cages and integrated with thiophene and alkylenedioxythiophene derivatives (3,4-ethylenedioxythiophene (EDOT) and 3,4-propylenedioxythiophene (ProDOT)) using Stille coupling reaction. The monomers, T-2-POSS, E-2-POSS, and P-2-POSS, were polymerized successfully via electrochemical and chemical polymerization techniques. As a fingerprint of D-A-D monomers, all monomers showed dual band characteristics due to intramolecular charge transfer. Soluble polymers exhibited reversible electrochromic responses electrochemically and chemically with fast switching times and high coloration efficiencies. E-2-POSS and its polymer PE2-POSS exhibited the lowest oxidation potential and band gap values as compared to their thiophene and ProDOT analogs. Also, P-2-POSS and its chemically obtained fluorescent polymer PP2-POSS-C represented high sensitivity towards Fe2+ and Fe3+ ions, which makes them potential candidates to be amenable for use in ion sensing. (C) 2021 Elsevier Ltd. All rights reserved.Article Citation - WoS: 14Citation - Scopus: 17Hybrid Nanocomposites of Elastomeric Polyurethane Containing Halloysite Nanotubes and Poss Nanoparticles: Tensile, Hardness, Damping and Abrasion Performance(Cambridge Univ Press, 2020) Mohamed, Salma Taher; Tirkes, Seha; Akar, Alinda Oyku; Tayfun, UmitThermoplastic polyurethane (TPU) matrix was reinforced with polyhedral oligomeric silsesquioxane (POSS) and halloysite nanotubes (HNT), both separately and combined. Composite samples were fabricated using a melt-compounding method. Characterization of the composites obtained was performed via tensile and hardness tests, melt-flow index measurements (MFI), abrasion tests, dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM) to investigate the mechanical performance, flow behaviour, tribological characteristics, thermo-mechanical response and morphological properties. The greatest tensile strength value was obtained for the smallest HNT content. Further addition of HNT resulted in agglomerations for both POSS and HNT particles. The shore hardness of TPU was enhanced by filler inclusions. The TPU/POSS composites displayed significant improvement in terms of abrasion resistance compared to TPU at lower loading levels. The DMA study showed that composites containing 0.5% POSS and 1.0% HNT displayed the greatest storage modulus. The glass-transition temperature of TPU shifted to smaller values with the addition of both nanoparticles. The HNT inclusions increased the MFI value of TPU because of their large aspect ratio. Homogeneous mixing of nanoparticles in the TPU matrix was confirmed by a SEM study of the composites. Their dispersion decreased as the concentrations of POSS and HNT increased. An adjuvant effect of POSS with HNT was achieved in their hybrid composites.Article Citation - WoS: 3Citation - Scopus: 2Polyhedral Oligomeric Silsesquioxane Cage Integrated Soluble and Fluorescent Poly(3,4-Propylenedioxythiophene) Dye(Elsevier Sci Ltd, 2021) Ertan, Salih; Kaya, Murat; Cihaner, AtillaA new analog of poly (3,4-propylenedioxythiophene) conjugated polymers called PProDOT-POSS, where polyhedral oligomeric silsesquioxane (POSS) nanocage with alkyl substitutions was integrated on the bridge of 3,4-propylenedioxythiophene unit and its structure was confirmed by spectroscopic techniques, was reported. The polymers were synthesized via both chemical and electrochemical polymerization techniques. While chemical polymerization was carried out in the presence of anhydrous FeCl3 as an oxidant, a solution of 0.1 M tetrabutylammonium hexafluoride electrolyte dissolved in a mixture of dichloromethane and acetonitrile (1/3: v/v) was used as an electrolyte solution for electrochemical polymerization. Electro-optical properties of the corresponding polymers were characterized by using electroanalytical techniques such as cyclic voltammetry and square wave potentiometry, and spectrophotometric methods like ultraviolet-visible and fluorescent spectrophotometry. Corresponding polymers obtained both electrochemically and chemically are soluble completely in common organic solvents such as chloroform, toluene, dichloromethane, tetrahydrofuran, etc. Polymer samples both in film and solution forms can be doped/dedoped reversibly by using a chemical oxidant or an external potential. The optical bandgap of the neutral polymer film with a maximum absorption band at 555 nm was calculated as 1.95 eV. Polymers have fluorescent property and excited polymers represented a red/orange light with an emission band centered at 605 nm in toluene. Also, PProDOT-POSS polymers have electrochromic properties under external potentials and they have an optical contrast of 55% at 555 nm between their neutral and oxidized states. Upon oxidation, they showed high transparency and they can switch between redox states in a short time (switching time = similar to 1.0 s) as well as high coloration efficiency (502 cm(2)/C for 95% switching). It can be concluded that POSS based PProDOT polymers can be good candidates for optoelectronic and bioelectronics applications. Short Abstract for Paper Submission: A new analog of poly (3,4-propylenedioxythiophene) conjugated polymers called PProDOT-POSS, was reported with the integrated of alkyl-substituted polyhedral oligomeric silsesquioxane nanocage structure. The polymers were synthesized via both chemical and electrochemical polymerization techniques. Corresponding polymers obtained both electrochemically and chemically are soluble completely in common organic solvents such as chloroform, toluene, dichloromethane, tetrahydrofuran, etc. Polymer samples both in film and solution forms can be doped/dedoped reversibly by using a chemical oxidant or an external potential. The optical bandgap of the neutral polymer film with a maximum absorption band at 555 nm was calculated as 1.95 eV. Polymers have fluorescent property and excited polymers represented a red/orange light with an emission band centered at 605 nm in toluene.
