Bıobased/ Bıodegradable/ Compostable / Antıbacterial Polymeric Mulching And Food Packagıng Films

In this thesis, novel biobased biodegradable compostable antibacterial St-g-PLA copolymers and St-g-PLA organoclay nanocomposites were fabricated by using different green methods applying as a food packaging and mulching films. The development of new methods for graft copolymerization of L-lactic acid onto starch were evaluated for the first time in the literature for this kind of monomers, such as supercritical carbon dioxide media, microwave irradiation, shear mixing method, and reactive extrusion without using toxic solvents and investigation of the St-g-PLA based film properties. Chemical and physical structures, thermal behavior and morphology of synthesized copolymers and nanocomposites, as well as some parameters were performed by FTIR and ¹³C CP MAS NMR spectroscopy, MALDI-TOF-MS, XRD, TGA DTG and SEM TEM, respectively. The film extrusion in a lab-scale was carried out by using a twin-screw extruder equipped by a film extrusion die, blowing unit and rotating film-uptake.Sunulan çalışmanın temel amacı biyoesaslı biyobozunur kompostedilebilir ve antibakteriyel özellikleri taşıyan nişasta-g-PLA ve nişasta-g-PLA organokil nanokompozitlerinin farklı yeşil teknolojiler yardımıyla sentezi, karakterizasyonu ve buradan elde edilen filmleri gıda ambalajı ve toprak örtü malzemesi olarak kullanabilmeyi gerçekleştirmektir. Tez kapsamında kullanılan ana monomerler (nişasta ve laktik asit) için hiç bir toksik çözücüden yararlanilmamasi ve sentezde süperkritik karbon dioksit, mikrodalga yöntemi, shear mixing ve reaktif ekstrüzyon yönteminden yararlanilmasi literatürde ilk defa rapor edilmiştir.Tez kapsamında elden edilen kopolimerler ve nanokompozitler için kimyasal, fiziksel, termal ve morfoloji yapı analizleri FTIR, ¹³C CP MAS NMR, MALDI-TOF-MS, XRD, TGA DTG ve SEM TEM teknikleri ile gerçekleştirilmiştir. Film ekstrüzyonu, çift vidali ekstrüdere bir üfleme-şişirme ünitesi monte edilerek film ekstrüzyon kafası ile gerçekleştirilmiştir

Fabrication and characterization of PVA/ODA-MMT-poly(MA-alt-1-octadecene)-g-graphene oxide e-spun nanofiber electrolytes and their response to bone cancer cells

WOS: 000370303600033PubMed: 26838849This work presents a new approach to fabrication and characterization of novel polymer nanofiber electrolytes from intercalated PVA/ODA-MMT nanocomposite as a matrix polymer and encapsulated graphene oxide (GO) nanosheets with amphiphilic reactive copolymer as partner polymers using electrospinning method. The chemical and physical structures, surface morphology, thermal behaviors and electric conductivity of nanocomposites and nanofibers were investigated using analyses methods including FTIR, XRD, SEM, DSC-TGA and conductivity analysis. Significant improvements in nanofiber morphology and size distribution were observed when GO and reactive organoclay were incorporated as reinforcement fillers into various matrix/partner solution blends. The structural factors of matrix-partner polymer nanocomposite particles with higher zeta-potential play important roles in both chemical and physical interfacial interactions and phase separation processing and also lead to the formation of nanofibers with unique surface morphologies and good conductivities. The cytotoxic, necrotic and apoptotic effects of chosen nanofibers on osteocarcinoma cells were also investigated. These multifunctional, self-assembled, nanofibrous surfaces can serve as semi-conductive and bioactive platforms in various electrochemical and bio-engineering processes, as well as reactive matrices used for the immobilization of various biopolymer pfecursors. (C) 2015 Elsevier B.V. All rights reserved.Turkish Scientific and Technological Research Council (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TBAG-HD/249, BIDEB-PD/2218]The authors thank the Turkish Scientific and Technological Research Council (TUBITAK) for the financial supports of this work through postdoctoral projects TBAG-HD/249 and BIDEB-PD/2218

Highly selective magnetic affinity purification of histidine-tagged proteins by Ni2+ carrying monodisperse composite microspheres

A magnetic sorbent with stable and superior magnetic behaviour was developed for His-tagged protein purification by immobilized metal affinity chromatography (IMAC). Magnetic, monodisperse and porous silica microspheres 6 mm in size, with bimodal pore size distribution including both mesoporous and macroporous compartments were synthesized as the base material by a staged-shape template hydrolysis \& condensation protocol. The magnetic microspheres were functionalized with iminodiacetic acid (IDA) and Ni2+ ions were attached onto the microspheres by metal-chelate formation via carboxyl groups. The saturation magnetization and carboxyl content of IDA attached magnetic silica microspheres were determined as 22.1 emu g(-1) and 19 mmol IDA g(-1) microspheres, respectively. A superior magnetic response with respect to the currently available IMAC sorbents in the form of composite magnetic nanoparticles was obtained with the proposed sorbent. The magnetic sorbent was utilized for the isolation of His-tagged green fluorescent protein (GFP) from E. coli lysate in batch-fashion. The maximum equilibrium GFP adsorption was ca. 87 mg GFP per g sorbent. GFP was isolated with high selectivity (>95\% purity) and isolation yields up to 68\% by changing the magnetic sorbent concentration. The superior isolation performance of the sorbent was explained by the presence of a bimodal pore structure including both macropores facilitating the intraparticular diffusion of GFP, and the mesopores serving a large surface area for parking and adsorption of GFP into the microbeads

Novel multifunctional colloidal carbohydrate nanofiber electrolytes with excellent conductivity and responses to bone cancer cells

Gokmen, Fatma Ozge/0000-0002-5548-8790WOS: 000361920900075PubMed: 26344321This work presents a new approach to fabricating novel polymer nanofiber composites (NFCs) from water solution blends of PVA (hydrolyzed 89%)/ODA-MMT and Na-CMC/ODA-MMT nanocomposites as well as their folic acid (FA) incorporated modifications (NC-3-FA and NC-4-FA) through green electrospinning nanotechnology. The chemical and physical structures and surface morphology of the nanofiber composites were confirmed. Significant improvements in nanofiber morphology and size distribution of the NFC-3-FA and NFC-4-FA nanofibers with lower average means 110 and 113 nm compared with those of NFC-1/NFC-2 nanofibers (270 and 323 nm) were observed. The structural elements of polymer NFCs, particularly loaded partner NC-2, plays an important role in chemical and physical interfacial interactions, phase separation processing and enables the formation of nanofibers with unique morphology and excellent conductivity (NFC-3-FA 3.25 x 10(-9) S/cm and NFC-4-FA 8.33 x 10(-4) S/cm). This is attributed to the higher surface contact areas and multifunctional self-assembled supramacromolecular nanostructures of amorphous colloidal electrolytes. The anticancer activity of FA-containing nanofibers against osteocarcinoma cells were evaluated by cytotoxicity, apoptotic and necrotic analysis methods. (C) 2015 Elsevier Ltd. All rights reserved.Turkish Scientific and Technological Research Council (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TBAG-HD/249, BIDEB-PD/2218]The authors would like to acknowledge the Turkish Scientific and Technological Research Council (TUBITAK) for the financial support of this work through postdoctoral projects TBAG-HD/249 and BIDEB-PD/2218

A Boronate Affinity-Assisted SERS Tag Equipped with a Sandwich System for Detection of Glycated Hemoglobin in the Hemolysate of Human Erythrocytes

Phenylboronic acid-functionalized, Ag shell-coated, magnetic, monodisperse polymethacrylate microspheres equipped with a glycoprotein-sensitive sandwich system were proposed as a surface-enhanced Raman scattering (SERS) substrate for quantitative determination of glycated hemoglobin (HbA1c). The magnetization of the SERS tag and the formation of the Ag shell on the magnetic support were achieved using the bifunctional reactivity of newly synthesized polymethacrylate microspheres. The hemolysate of human red blood cells containing both HbA1c and nonglycated hemoglobin was used for determination of HbA1c. The working principle of the proposed SERS tag is based on the immobilization of HbA1c by cyclic boronate ester formation between glycosyl residues of HbA1c and boronic acid groups of magnetic polymethacrylate microspheres and the binding of <i>p</i>-aminothiophenol (PATP)-functionalized Ag nanoparticles (Ag NPs) carrying another boronic acid ligand via cyclic boronate ester formation via unused glycosyl groups of bound HbA1c. Then, in situ formation of a Raman reporter, 4,4′-dimercaptoazobenzene from PATP under 785 nm laser irradiation allowed for the quantification of HbA1c bound onto the magnetic SERS tag, which was proportional to the HbA1c concentration in the hemolysate of human erythrocytes. The sandwich system provided a significant enhancement in the SERS signal intensity due to the plasmon coupling between Ag NPs and Ag shell-coated magnetic microspheres, and low HbA1c concentrations down to 50 ng/mL could be detected. The calibration curve obtained with a high correlation coefficient between the SERS signal intensity and HbA1c level showed the usability of the SERS protocol for the determination of the HbA1c level in any person