Yazar "Solmaz, Mehmet Ertugrul" seçeneğine göre listele

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    Colorimetric Bisphenol-A Detection With a Portable Smartphone-Based Spectrometer
    (Ieee-Inst Electrical Electronics Engineers Inc, 2018) Bayram, Abdullah; Horzum, Nesrin; Metin, Aysegul Ulku; Kilic, Volkan; Solmaz, Mehmet Ertugrul
    Water quality monitoring in resource-limited settings without access to a sophisticated laboratory requires the development of low cost and portable instrumentation. Herein, we propose a newly designed handheld reflection-based smart-phone sensing platform to detect Bisphenol-A (BPA), a well-known endocrine disruptor agent abundantly used in plastic industry. An experimental investigation relying on color change due to the formation of quinone-type complex was conducted with samples from two different water sources: distilled and commercial drinking water. This colorimetric measurement device was used to determine BPA in distilled water in alkaline environments. The successful combination of colorimetric assay and spectrometer facilitates limit of detection in the low ppm levels, 0.29 ppm for smartphone and 0.23 ppm for commercial spectrometer, with a sensitivity of 0.1/ppm.
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    Poly (methyl vinyl ether-co-maleic acid) - Pectin based hydrogel-forming systems: Gel, film, and microneedles
    (Elsevier Science Bv, 2017) Demir, Yusuf Kemal; Metin, Aysegul Ulku; Satiroglu, Betul; Solmaz, Mehmet Ertugrul; Kayser, Veysel; Maeder, Karsten
    Cross-linking of natural and synthetic polymers is widely explored to achieve the desired material properties (mechanical strength, drug loading capacity, swelling and erosion rates). However, the potential of polymers produced by crosslinking poly (methyl vinyl ether-co-maleic acid) (PMVE/IVIA) and pectin (PE) in pharmaceutics is mainly unexplored so far. We have investigated the effect of various esterification conditions and pectin content on the physicochemical properties. Materials have been characterized by fourier transform infrared, differential scanning calorimetry and scanning electron microscopy. In addition, swelling and bioadhesive features of PMVE/MA-PE hydrogel systems were investigated. A band shift for the carbonyl group from 1706 to 1776 cm(-1), and glass transition (Tg) increased from 55.4 +/- 0.9 degrees C to 119.5 +/- 0.3 degrees C confirmed the formation of esterification reaction within the cross-linked films. Cross-linked PMVE/MA:PE films with a ratio of 5 demonstrated a superior mass increase when compared to 2.5, 3.125, 3.75, 6.25, and 7.5 ratios of the same hydrogel film. Formulations containing PMVE/MA and pectin with a ratio of 3.75 showed superior bioadhesive features. For the first time, we engineered three-dimensional printing based swell-able microneedle arrays made out of cross-linked PMVE/MA-PE. Microneedle arrays height and aspect ratio were ranged from 702.5 +/- 11.9 mu m to 726 +/- 23.3 mu m and 3.12 +/- 0.20 to 3.29 +/- 0.21, respectively. Cross-linked PMVE/MA-PE Microneedle arrays (10-2, 24 h) indicated the least height loss, 22.33 +/- 4.15%, during axial compression test; whilst, transverse failure of cross-linked PMVE/MA-PE Microneedle arrays was varied from 0.15 +/- 0.05 to 0.25 +/- 0.04 N/needle. In conclusion, we obtained a novel cross-linked polymer system with promising features of drug delivery and bio-analytical applications. (C) 2017 Elsevier B.V. All rights reserved.