LEE- Nano Bilim ve Nano Mühendislik-Yüksek Lisans
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Sustainable Development Goal "Goal 3: Good Health and Well-being" ile LEE- Nano Bilim ve Nano Mühendislik-Yüksek Lisans'a göz atma
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Öge3D printed antibacterial herbal loaded alginate-pectin medical patch: Fabrication and characterization(Graduate School, 2022-07-07) Dini, Ghazaleh ; Benli, Birgül ; 513201032 ; Nanoscience and NanoengineeringThis thesis focuses on a comprehensive and multi-disciplinary approach to the development of an effective and sustainable wound dressing. The thesis consists of three main parts, each layer building upon the previous to create a final product that is both innovative and practical. In the first part, the necessary materials such as pectin was synthesized in order to serve as the base layer of the wound dressing. This involves careful selection and testing of materials to ensure that it meets the necessary requirements for strength, flexibility, and biocompatibility. In the second part of the thesis, the antibacterial agents from herbal extracts were prepared. These natural agents offer several advantages over synthetic alternatives, including reduced toxicity and improved biocompatibility. Also, natural and biocompatible nanoclay as a carrier for these agents were used to controlled release, with the assistance of synthesized cellulose which was extracted from waste fruits, expected effects were improved, and targeted delivery to the wound area. In the third and final part of the thesis, advanced 3D printing technology was used in two ways. Firstly, a skeleton was designed for the prepared hydrogels using 3D printing. This skeleton provides structure and support for the hydrogel while allowing for air flow and moisture control. Secondly, the polymers (pectin:alginate/gelatin and nanoclay loaded ones themselves were 3D printed using Fused Deposition Modeling (FDM). We also integrated the hydrogel and clay material to form more hydrophilic film patch that is both strong and flexible. The final product is an antibacterial wound dressing that combines advanced materials and technologies to promote healing and prevent infection. This innovative approach has the potential to revolutionize wound care and improve patient outcomes. As it has been demonstrated in literature, wound healing is a complex and intricate process that involves multiple stages and requires the right type of dressings to prevent infection and promote the regrowth of tissue. The ideal dressing should have several key properties, including the ability to keep the wound moist, allow air to flow through, protect the wound from external contaminants, absorb excess fluid, and be easy to remove without causing additional damage to the wound. Hydrogels are an excellent choice for wound dressings due to their unique physical and chemical properties. These materials are highly absorbent and can retain large amounts of water, which helps to keep the wound moist and promote healing. A hydrophilic wound dressing is necessary for rapid therapeutic effect and absorption of exudate. This characteristic also helps to maintain a moist environment, promote high blood absorption, and enhance erosion capability and it was measured with contact angles. They are also permeable to gases, allowing air to flow through and providing xx oxygen to the wound. Additionally, hydrogels can be formulated to have antimicrobial properties, which can help to fight against bacteria and prevent infection. In this thesis, pectin was synthesized from pomegranate and grapefruit peels using citric acid extraction and cellulose was synthesized from pomegranate peels, making the study sustainable and environmentally friendly. Also, the fallen fruits from the grapefruit trees in the faculty garden were collected and utilized in the study, emphasizing their significant contribution to the fruit industry and agricultural research. Additionally, the effect of grapefruit juice instead of citric acid was alternatively used during the process of pectin extraction with the aim of achieving zero waste. Malva sylvestris and Cichorium intybus L, two local Turkish herbs, were used as antibacterial agents. The extraction of these herbs was done using microwave-assisted extraction with ethanol and membrane-assisted purification methods. Additionally, dialysis tubes which are kind of membrane, were used during the purification of antibacterial herbal extracts and the resulted extracts were compared with traditional extraction methods. The synthesized extracts were analyzed using optical spectroscopy techniques such as UV-Vis Absorption Spectroscopy. Herbal extracts were loaded into Halloysite nanotubes (HNTs) and injected into the hydrogel pores in order to help with air flow in the hydrogel area. Glycerol also used as a plasticizer. The process of extracting materials from plants and fruit wastes was also carried out using microwave-assisted synthesis methods, which are low-cost and time-efficient. The effectiveness of Malva sylvestris and Cichorium intybus L against bacteria was examined using the disc diffusion method. Their antibacterial activities were tested against E. coli and S. aurous that are effective two common types of wound bacteria to create pectin/alginate-based hydrogel wound dressings. Disc diffusion tests confirmed the antibacterial activity of the chosen plant extracts against common wound bacteria. To improve the effect of nanotubes such as high water absorbency and elongation as fillers of reinforced hydrogels composites, cellulose was synthesized. Ash content tests and moisture level measurements of the synthesized pectin and cellulose confirmed their high purity. In the next stage of the thesis, biopolymers and HNTs were combined to form a composite that was used to formulate a hydrogel that could be used inside a 3D printed skeleton. To design an effective antibacterial patch, 3D FDM printer were used. A patch-shaped skeleton with several pins were designed using 3D printing technology to make the hydrogel porous masks. The pectin/alginate based composites were poured on top of a cross-linker solution to form the hydrogel on the mask surface. Then, the pectin/alginate based hydrogels were cross-linked with calcium chloride (CaCl2). In the final stage of the thesis, formulated layer from cellulose and HNTs composite were prepared. These nanoclays were designed to act as carriers for herbal extracts. The effectiveness of these hydrogels in preventing bacterial growth was also tested against common wound bacteria, E coli and S. aurous and the results were successful. Additionally, the ability of these hydrogels to absorb water was evaluated using a gelatin hydration test. The behavior of the hydrogels was also examined in detail. In conclusion, the results showed that hydrogels containing either Malva sylvestris or Cichorium intybus L plant extract have great potential as antibacterial patches for xxi wound dressing. However, further in vivo studies are necessary before any clinical application can be made.
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ÖgeFabrication of multi-component superparamagnetic nanoparticles and magnetic heating performance for hyperthermia cancer therapy(Graduate School, 2021-02-16) Çetin, Ayşesimay ; Kılıç, Ali ; 513171012 ; Nanoscience and NanoengineeringNowadays, cancer has become a major public health problem worldwide. It is known that 19.3 million new cancer cases and approximately 10 million cancer deaths occurred worldwide in 2020 alone. The TUIK 2020 report, the cancer is in second place with 80,186 people in Turkey ranking of causes of death. Traditional methods such as chemotherapy, radiotherapy and surgery do not give highly successful results in cancer stages that have spread in the body. These treatment methods carry fatal risks by damaging healthy tissues depending on the treatment method in the patient. For this reason, various treatment methods have been developed that are expected to affect only damaged tissue. Hyperthermia is one of the methods developed for this purpose. Multilayer functional superparamagnetic nanoparticles (NPs) are used in the method, which can be used in medical imaging and treatment applications. With these NPs, it is tried to develop the use of optical and magnetic methods for both diagnosis and treatment of cancer. Thanks to a dielectric shell coated on the NPs, its agglomeration can be prevented, and thanks to an organic shell coated on it, its properties such as biocompatibility and stability can be increased, as well as various molecule adhesion capabilities for treatment purposes can be given to the surfaces of the NPs. In addition to the magnetic properties of these NPs, it will be possible to heat them with the near infrared (NIR) laser to be applied due to their surface plasmon resonance properties. Basically in this method; It is aimed to; (a) reach the denaturation temperature (42ºC) of the cancer cells by applying an alternative magnetic field that will affect only the tumor area, and (b) the malignant cells are destroyed by heating while the other healthy tissues remain stable. In this way, the side effects that occur in traditional methods are tried to be minimized. The two most important factors determining the use of magnetic NPs in hyperthermia therapy are; (a) the applied NPs must have a high ability to heat the cancerous tissue to the desired temperature and (b) heating should be limited only to the cancerous tissue. These two factors can be achieved by having excellent magnetic properties that can reach the target temperature by using a small amount of NPs in the target tissue. For this reason, the type of magnetic NPs used and their magnetic heating performance are of great importance. Studies on various NPs such as Fe3O4, MnFe2O4 are quite common, but it becomes impossible to compare the experimental results due to the different methods and different environmental conditions determined for NPs fabrication in the studies. Therefore, more research is needed to make hyperthermia treatment available. In the thesis, in the first part, Fe3O4, MgFe2O4, MnFe2O4 and SrFe12O19 NPs were synthesiszed as cores. Later, their outher surface was first coated with SiO2 layer, functionalized with amination, then decorated via Au NPs and consequently the outer surface of overall NPs will be coated via PEG. After each coating, the NPs have been characterized using FTIR, SEM and EDX. Heating process was carried out under AMF, using induction generator, in water and in agar according to the rate calculation of 0.1% (v/m) of the produced NPs. According to the results of the heating tests, among all samples, SrFe12O19 NPs showed the lowest and MgFe2O4 NPs showed the highest heating performance among all samples in the tests where different core types were compared. According to the heating results comparing the different coating stages, the aminated NPs gave the fastest warming result among the other coating stages. Comparing different coating steps, PEG coated samples gave the slowest heating result in the heating results. In addition, the heating performance of gold-coated samples, which is the previous coating step from PEG, is very close to that of PEG coated samples and gave the second lowest performance. As a result, our study has shown that different coating stages and NPs differences change the heating performance of superparamagnetic NPs. Although there are many studies of magnetic NPs in the literature, the effects of different types of magnetic NPs on the heating performance of different coating stages of these NPs were compared under standardized laboratory conditions. It is possible to say that this study, which is carried out with easily accessible and economical laboratory materials, is illuminating for future researches related to the subject.
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ÖgeSynthesis of folate receptor 1 targeted dye-conjugated peptides for use in positron emission tomography imaging systems(Graduate School, 2022-01-26) Cin, Derya ; Alptürk, Onur ; Yılmaz, Özgür ; 513191022 ; Nanoscience and Nanoengineering ; Nano Bilim ve Nano MühendislikNowadays, it is tried to find solutions for human beings to have a long and high-quality life, increase the number of studies in the field of health, and detect diseases that become difficult to treat with their progress. Cancer is one of the first causes of death statistics in official records in the world and Turkey. It is known that the diagnosis of cancer is difficult and takes time, and the number of cases continues to increase rapidly day by day. Because of the metabolism change in cancer cells, the cells continue to grow and divide instead of dying. Cancer factors; inherited mutations can be internal, such as hormones, or acquired environmental, such as carcinogens, radiation, infectious organisms, and lifestyle. By imaging the changes caused by cancer in cells, information about the stage of cancer can be obtained. Cancer researchers want to detect cells where cancers develop, identify biomarkers of cancers early, and create treatment plans for cancer. Proteins produced by tumor cells can be used as biomarkers to evaluate disease processes. Molecular imaging (MI) aims to combine patient and disease-specific molecular information and is an interdisciplinary area covering a wide range of sciences when is used in the diagnosis and treatment of diverse disease genres. For this purpose, targeted cell-specific chemical biomolecules are delivered to the organism by labeled radioactive isotopes. The imaging method to be utilized varies specifically according to the disease state. Positron emission tomography (PET), which has become more advanced with the integration of scanners such as computerized tomography (CT) used in the imaging of cancer, is one of the several imaging methods widely used in the diagnosis of cancer today. Since radioisotope imaging agents are required for imaging in PET devices, studies for their development are increasing day by day. Peptides are used as ligands/agents in imaging cancer imaging, thanks to their properties such as high selectivity and high affinity, ease of synthesis and chemical stability, quick removal from blood, and low immunogenicity/safety for cell surface proteins. Due to the metabolic rate of cancer cells, more folic acid is produced in these cells than in normal healthy body cells, and this uncontrolled increase has led to its use in cancer imaging studies. Peptide-based imaging agents are used for molecular imaging by binding to target cancer receptors such as Folate Receptor 1 (FOLR1) of tumor cells. Molecules that can bind to the FOLR1 receptor with high sensitivity and affinity were synthesized by the Solid Phase Peptide Synthesis (SPPS) method. The peptides KWGFR, KLWWN, KFLSW, KWIAG, KWSYW, KGWRN, and KSYFA were selected from the peptide library and successfully synthesized. Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) was used to purify the peptides and Liquid Chromatography-Mass Spectrometry (LC-MS) was utilized for peptide characterization. Finally, the imaging agent will be obtained by conjugating the peptide-based signaling agent labeled with the 68Ga isotope.