Zeolit ince filmlerinin biyosensör uygulamalarına yönelik olarak hazırlanması ve araştırılması

TÜBİTAK MAG Proje01.03.2012Zeolites plays an important role in the immobilization of biomolecules with their tunable surface properties, adjustable surface charge and hydrophilicity, which is a function of crystal Si/Al ratio. These properties make zeolites promising alternative candidates for the immobilization of enzymes and incorporation into biosensing devices. The objective of the project is to successfully assemble individual pieces of elements, such as different nanomaterials, biological compounds, and transducers into each other in order to study the role of nanomaterials in the assembled piece of work. For this purpose, zeolites and zeo-type materials with varying characteristics were synthesized; zeolite thin films were made and microfabricated to obtain different zeolite patterns from the synthesized materials; immobilization of biologic compounds were investigated onto these thin films; and finally different types of electrochemical biosensors were fabricated using these individual pieces to obtain actual data out of the integrated devices in order to discuss the role and significance of the nanomaterials for biosensors. During the first phase of the project, micron and nano sized zeolite materials with homogenous particle size and varied Si/Al ratio were synthesized and modified by using different techniques. Throughout the project, all zeolites that were aimed to be produced were successfully synthesized and modified by either applying ionexchange protocols or changing surface groups. During the second phase, zeolite particles were attached onto SiO2 surfaces to obtain zeolite thin films. For this purpose, the quality of the obtained thin films, their potentiality to be used in biosensors and thier use in cell attachement applications were investigated by studying the changing zeolite parameters such as the morphology, varying particle size, changing Si/Al ratio and thus the changing hydrophilic/hydrophobic surface properties of zeolites. The third phase of the project involves immobilization of different biological compounds onto the obtained zeolites and their thin films and then to actually gather biosensor data from the assembled piece of device. Next phase of the project involves obtaining performance characteristics of biosensors such as stability, life time, and inhibition using these assembled pieces. During the last stage of our project, all zeolite thin films that were microfabricated were subjected to cell attachment tests using osteoblasts and fibroblasts and the number of cells were counted using MTT tests. In this way, it was possible to control the number of zeolites in the micropatterns and it was found that this number directly correlated with the number of cells that were attached and their proliferation was investigated as a function of attached zeolites

Study of zeolite influence on analytical characteristics of urea biosensor based on ion-selective field-effect transistors

A possibility of the creation of potentiometric biosensor by adsorption of enzyme urease on zeolite was investigated. Several variants of zeolites (nano beta, calcinated nano beta, silicalite, and nano L) were chosen for experiments. The surface of pH-sensitive field-effect transistors was modified with particles of zeolites, and then the enzyme was adsorbed. As a control, we used the method of enzyme immobilization in glutaraldehyde vapour (without zeolites). It was shown that all used zeolites can serve as adsorbents (with different effectiveness). The biosensors obtained by urease adsorption on zeolites were characterized by good analytical parameters (signal reproducibility, linear range, detection limit and the minimal drift factor of a baseline). In this work, it was shown that modification of the surface of pH-sensitive field-effect transistors with zeolites can improve some characteristics of biosensors

Titanyumsilikat Ets-10 Nano Kristallerinin Modifiye Edilmesi Ve İnce Film Yapımının Araştırılması

Teklif edilen projenin genel amacı, güneş pilleri ve sensörler gibi farklı uygulama alanlarına yönelik olarak optik açıdan duyarlı ve kontrol edilebilir özelliklere sahip yeni malzemelerin geliştirilmesi için ilk olarak ETS-10 ince film yapımının üç farklı yöntemle araştırılmasıdır. ETS-10 kristallerinden cam veya iletkenlik sağlama özelliği açısından ITO kaplanmış cam yüzeyler üzerinde ince film yapılacak ve bu filmlerin yapısal özellikleri SEM, XRD, TEM, XRF, XPS, UV-vis ve Raman spektroskopisi yöntemleriyle araştırılacaktır. ETS-10 kristali grubumuz tarafından modellenecektir. Bütün bu deneysel çalışmalara ek olarak ETS-10 ve gümüş nanoparçacıklarının etkileşiminin atomik boyuttaki detayları ise yük yoğunluğu fonksiyoneli teorisi (density functional theory – DFT) ile hesaplanacaktır. Bu çalışmanın teorik kısmında ETS-10 yapısını oluşturan gözeneklerde gümüş oluşumunun atomik ölçekteki detayları Quantum-ESPRESSO program süiti yardımıyla daha önce literatürde kullanılmış olan model birim hücre kullanılarak incelenecektir. Mikrogözenekli malzemelerin bu amaçlar doğrultusunda araştırılması konusunun literatürde başka bir örneği daha yoktur ve böyle bir çalışma kimya mühendisliği, malzeme mühendisliği, fizik ve elektrik mühendisliği alt yapısından gelen bilim insanlarının nanoteknoloji interdisiplini şemsiyesinde ilk defa olarak grubumuz tarafından yapılmış olacaktır

Nanosensors based on nanomaterials (NANOBIOSENS)

The primary objective of this proposal is to bring together an international and interdisciplinary group of research teams who have different expertise areas to share the knowledge of different elements for building nano-biosensors. The development of future devices requires controlled assembly and placement of individual and/or multiple nano building blocks into the desired locations. By the accomplishment of this research proposal, the advantages of integration of nanomaterials into the structure of biosensors will be feasible. It is expected that the nanomaterial assembled biosensor structures will show an enhanced sensitivity due to the high surface area, higher porosity, and adjusted surface energy. In this research proposal, there are six participants from six countries with different expertise areas in the field of chemical engineering, biomedical engineering, materials science, physics, chemistry, and biology. Different pieces of work will thus be constructed into each other to first of all study their “separate” roles in that assembled piece of work. The international and interdisciplinary group of research team who came together is composed of Turkey, France, Ukraine, Canada, United States and (Rep. of) Korea. The estimated time of the project is 36 months. The proposed programme consists of three stages. STAGE 1 consists of shortly “synthesis of nanomaterials and their controlled assembly and organization of Si wafer substrates”. STAGE 2 is composed of the “biofunctionalization” of these materials built in STAGE 1 and the building a biosensor out of the assembled materials. STAGE 3 will focus on the “field tests” to see how affective these biosensors are working. Six trainings, three general meetings and three workshops are being planned for this research proposal in order to share all the knowledge and information gained throughout the work and to form the basis of long lasting collaborations.EU, Funded under :FP7-PEOPLE-IRSES-200

INTEGRATED NANODEVICES (NANODEV)

The primary objective of this proposal is to carry the results, knowledge, and international collaboration gained throughout our first project (NANOBIOSOENS) that was conducted as a part of IRSES call in the last 3 years to the next level, which will focus on nanodevices and advanced applications. The proposed research project is focused on two different applications, main one being on biosensors and bioelectronics and the other one on potential solar energy science. The results obtained during NANOBIOSENS were very promising opening interesting possibilities to more detailed investigations, which produced around 25 publications with around 50 conference presentations. At the end of the NANOBIOSENS project, our success was published in the PROJECTS magazine as “Biosensors Received the Nanotreatment”. The obtained results along with the synergy formed among these 6 international partners motivated us to carry our research to a more advanced level. With this motivation, the objective of the currently proposed project is to test the synthesized and integrated nanomaterials in two of the most appealing applications that are “biosystems and solar energy”. This had been the motivation for this group to continue the researcher and knowledge exchanges for the above mentioned higher level of scientific objective that is hoped to be achieved throughout the proposed NANODEV project. In terms of participants, there will be two main distinctions of NANODEV with respect to the NANOBIOSENS project. The first one is our new partner who joined us from CHINA and is an expert in the field of nanomaterial synthesis, design of new bioactive compounds, and biosensor development. The second distinction is the newly built research center at METU, Center for Solar Energy Research and Applications. With these two additional assets, it will be possible in NANODEV to test the jointly made nanomaterial integrated compounds in two different fields of applications.FP7-PEOPLE-2012-IRSE

Oriented assembly and nanofabrication of zeolite A monolayers

A facile and efficient method in order to assemble zeolites for the purpose of generating zeolite nano-micropatterns on the Si wafer was investigated by using e-beam lithography. A monolayer of organized. fully covered and strongly bound zeolite A nanocrystals were formed on the Si wafer substrates without using any chemical linkers. The limits of forming nano sized zeolite A patterns on the Si wafer was tested and it was observed that zeolite A nanocrystals could be assembled on the Si wafers with high precision The limit of the pattern resolution was defined by the size of the zeolite nanocrystal, which was around 250 nm in the Current study. Furthermore, mono and double layers of zeolite A nanocrystals were generated without using any chemical linkers oil the Substrates for the first time. (C) 2009 Elsevier Inc. All rights reserve

İLERİDEKİ UYGULAMALARDA KULLANILMAK ÜZERE ANTİBAKTERİYEL ZEOLİT İNCE FİLMLERİN ESNEK YÜZEYLER ÜZERİNDE OLUŞTURULMASI

İLERİDEKİ UYGULAMALARDA KULLANILMAK ÜZERE ANTİBAKTERİYEL ZEOLİT İNCE FİLMLERİN ESNEK YÜZEYLER ÜZERİNDE OLUŞTURULMAS

The Effect of Defects Created in Microporous Vanadosilicate AM-6 Thin Films in Photocatalysis

Micro and Nanotechnology Department, Middle East Technical University, Ankara, , Turkey The development of visible-light effective photocatalysts allows low cost degradation of toxic non-biodegradable organic pollutants. Vanadium, present in a specific oxidation state within the structure of SiO2 matrix could open up the gateway to investigate and tailor the defects created for such photocatalytic applications. Vanadosilicate AM-6, which is a large pore microporous material containing semiconducting monatomic …V-O-V-O-V… chains embedded in a silica matrix has recently been demonstrated to exhibit photocatalytic activity in the visible light range. Pore regularity, control of defects, and the presence of stoichiometric amounts of in AM-6 allows one to create alternative materials in visible-light photocatalysis. Accordingly, vanadosilicate AM-6 thin films with controlled defect sites were produced by tailoring the V5+/V4+ ratio within the thin film structure . Furthermore, the effect of changing molar composition and vanadium source used for the secondary growth was also investigated systematically. V5+/V4+ ratio was tailored systematically by controlling the defect concentration of seed crystals during the film growth and vanadium source with alternating V5+ concentration. It was found that vanadosilicate AM-6 films with higher amount of V5+ ions arising from different synthesis conditions possess better photocatalytic activity under visible light irradiation for the degradation of MB, which can be attributed to the presence of V5+ cation within the framework of AM-6. Photocatalyst production in the form of thin film provides integration of the material to device-oriented applications and also accelerates the degradation kinetics between the pollutant and the photocatalyst due to the controlled defect formation leading to enhanced photocatalytic activity under visible light

TİMOL ORGANİK BİLEŞİĞİNİN MEZO-ZEOLİT X YÜZEYİNE BAĞLANMASI

Zeolitler, Aluminosilikat içeren inorganik kristallerdir. İçerdikleri nanometre boyutlarındaki gözeneklerin sayısı, dağılımı ve genişliği bu zeolitlerin yüzey alanlarının diğer tüm katılara göre çok daha büyük olmasını sağlar. Zeolitlerin gözenek kanallarının düzeni ve boyutları, sentez sonrası işlemlere tabi tutularak istenildiği gibi değiştirebilir. Yapılarındaki bu çeşitlilik olanağı, zeolitlerin, konuk-konak sistemleri için uygun konak görevi görmesini sağlamaktadır. Çeşitli gözenek boyutlarına sahip zeolitlerin, farklı organik moleküller için konak olarak kullanıldığı bilinmektedir. Proje ekibinde yer alan öğretim üyesi, Doç. Dr. Burcu Akata Kurç ve doktora öğrencisi Melda İşler Binay, zeolitlerin çeşitli kullanım amaçları için sentezlenmesi ve modifikasyonu konularında çalışmaktadırlar. Bu çalışmada amaç, öncelikle zeolit X sentezlenip, sonrasında sentez-sonrası işlemler ile mezo-gözenekli zeolit X üretimidir. İkinci amaç ise, “timol” adlı organik bileşik sentezlenen zeolit X yüzeyine tutturma ve son ürünün antibakteriyel etkinliği hakkında bilgi edinmektir. Önerilen çalışmadan elde edilecek bilgiler ışığında, literatüre mezo-gözenekli zeolit X sentezi ve konak özelliği hakkında katkıda bulunulacaktır