| 1. |
- Ali, Syed M. Usman
(författare)
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Fabrication and characterization of ZnO nanostructures for sensing and photonic device applications
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nanotechnology is an emerging inter-disciplinary paradigm which encompasses diverse fields of science and engineering converge at the nanoscale. This nanoscale science and nanostructure engineering have well demonstrated in the fabrication of sensors/transducers devices with faster response time and better sensitivity then the planer version of the sensor’s configurations. Nanotechnology is not just to grow/fabricate nanostructures by just mixing nanoscale materials together but it requires the ability to understand and to precisely manipulate and control of the developed nanomaterials in a useful way. Nanotechnology is aiding to substantially improve, even revolutionize, many technology and industry sectors like information technology, energy, environmental science, medicine/medical instrumentation, homeland security, food safety, and transportation, among many others. Such applications of nanotechnology are delivering in both expected and unexpected ways on nanotechnology’s promise to benefit the society.The semiconductor ZnO with wide band gap (~ 3.37 eV) is a distinguish and unique material and its nanostructures have attracted great attention among the researchers due to its peculiar properties such as large exciton binding energy (60 meV) at room temperature, the high electron mobility, high thermal conductivity, good transparency and easiness of fabricating it in the different type of nanostructures. Based on all these fascinating properties, ZnO have been chosen as a suitable material for the fabrication of photonic, transducers/sensors, piezoelectric, transparent and spin electronics devices etc. The objective of the current study is to highlight the recent developments in materials and techniques for electrochemical sensing and hetrostructure light emitting diodes (LEDs) luminescence properties based on the different ZnO nanostructures. The sensor devices fabricated and characterized in the work were applied to determine and monitor the real changes of the chemical or biochemical species. We have successfully demonstrated the application of our fabricated devices as primary transducers/sensors for the determination of extracellular glucose and the glucose inside the human fat cells and frog cells using the potentiometric technique. Moreover, the fabricated ZnO based nanosensors have also been applied for the selective determination of uric acid, urea and metal ions successfully. This thesis relates specifically to zinc oxide nanostructure based electrochemical sensors and photonic device (LED) applications.
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| 2. |
- Fytory, Mostafa, et al.
(författare)
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Core-Shell Nanostructured Drug Delivery Platform Based on Biocompatible Metal-Organic Framework-Ligated Polyethyleneimine for Targeted Hepatocellular Carcinoma Therapy
- 2023
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Ingår i: ACS Omega. - : AMER CHEMICAL SOC. - 2470-1343. ; 8:23, s. 20779-20791
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Tidskriftsartikel (refereegranskat)abstract
- Multifunctional nanosized metal-organic frameworks(NMOFs)have advanced rapidly over the past decade to develop drug deliverysystems (DDSs). These material systems still lack precise and selectivecellular targeting, as well as the fast release of the quantity ofdrugs that are simply adsorbed within and on the external surfaceof nanocarriers, which hinders their application in the drug delivery.Herein, we designed a biocompatible Zr-based NMOF with an engineeredcore and the hepatic tumor-targeting ligand, glycyrrhetinic acid graftedto polyethyleneimine (PEI) as the shell. The improved core-shellserves as a superior nanoplatform for efficient controlled and activedelivery of the anticancer drug doxorubicin (DOX) against hepaticcancer cells (HepG2 cells). In addition to their high loading capacityof 23%, the developed nanostructure DOX@NMOF-PEI-GA showed an acidicpH-stimulated response and extended the drug release time to 9 daysas well as enhanced the selectivity toward the tumor cells. Interestingly,the DOX-free nanostructures showed a minimal toxic effect on bothnormal human skin fibroblast (HSF) and hepatic cancer cell line (HepG2),but the DOX-loaded nanostructures exhibited a superior killing effecttoward the hepatic tumor, thus opening the way for the active drugdelivery and achieving efficient cancer therapy applications.
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| 3. |
- Hernández-Neuta, Iván, 1986-
(författare)
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Nucleic acid analysis tools : Novel technologies and biomedical applications
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nucleic acids are fundamental molecules of living organisms functioning essentially as the molecular information carriers of life. From how an organism is built to how it responds to external conditions, all of it, can be found in the form of nucleic acid sequences inside every single cell of every life form on earth.Therefore, accessing these sequences provides key information regarding the molecular identity and functional state of any living organism, this is very useful for areas like biomedicine, where accessing and understanding these molecular signatures is the key to develop strategies to understand, treat and diagnose diseases.Decades of research and technological advancements have led to the development of a number of molecular tools and engineering technologies that allow accessing the information contained in the nucleic acids. This thesis provides a general overview of the tools and technologies available for nucleic acid analysis, and proposes an illustrative concept on how molecular tools and emergent technologies can be combined in a modular fashion to design methods for addressing different biomedical questions. The studies included in this thesis, are focused on the particular use of the molecular tools named: padlock and selector probes, rolling circle amplification, and fluorescence detection of single molecules in combination with microfluidics and portable microscopy. By using this combination, it became possible to design and demonstrate novel approaches for integrated nucleic acid analysis, inexpensive digital quantification, mobile-phone based diagnostics and the description of viral infections.These studies represent a step forward towards the adoption of the selected group of tools and technologies, for the design and building of methods that can be used as powerful alternatives to conventional tools used in molecular diagnostics and virology.
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| 4. |
- Hölzel, Ralph, et al.
(författare)
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Holzel et al. Reply
- 2006
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Ingår i: Phys. Rev. Lett.. - 0031-9007 .- 1079-7114. ; 96
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Tidskriftsartikel (refereegranskat)abstract
- A Reply to the Comment by Liming Ying, Dejian Zhou, and Andreas Bruckbauer.
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| 5. |
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| 6. |
- Razmi, Nasrin, 1989-
(författare)
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(Nano)materials for electrochemical sensing applications in different fields
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Health care and the medical industry, environmental monitoring and food sector are just a few examples of human’s major concerns. Design and analytical applications of (bio)sensors and sensing (nano)materials in these fields which have drawn tremendous attention by scientific community, require multidisciplinary knowledge in materials, transducers, and measurement methodologies. Among different types of transducers, electrochemical transducers have gained a lot of interest due to their simplicity, ease of fabrication and integration, selectivity, and sensitivity. Application of sensing materials, in particular nanomaterials, provide several improvements for analytical sensing such as selectivity, sensitivity, robustness, and fast response. Therefore, different nanomaterials due to their excellent characterization are exploited as key instruments for the design of high-performant analytical assays in various fields.Considering this established nanomaterial-based electrochemical sensing applications as alternatives to conventional methods in various fields, in this thesis, we synthesized and characterized some (nano)materials such as gold nanostars (AuNSs), iron oxide/zinc oxide (α-Fe2O3/ZnO) nanocomposite for sensing applications in environmental monitoring. We fabricated screen printed Ruthenium (IV) oxide (RuO2-Nf) pH electrodes and applied them for continuous pH monitoring in milk and during milk coagulation. Although the results indicated the applicability of the RuO2-Nf electrodes for continuous pH measurement in milk as a replacement of traditional glass electrode, they are not suitable for more viscous samples. Later we investigated the cleaning procedure for these pH electrodes, and we showed that soaking them in the solution of 5% pepsin in 0.1 M HCl restores the electrodes to their initial state for pH measurement in food samples. In another work we developed a molecular imprinted polymer-based biosensor for successful detection of prostate-specific antigen. At the end we investigated the effect of pH on the growth of pathogenic bacteria using electrical impedance spectroscopy.
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| 7. |
- Schmitz-Hertzberg, Sebastian-Tim, et al.
(författare)
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Multifactorial design of poly(d,l-lactic-co-glycolic acid) capsules with various release properties for differently sized filling agents
- 2013
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Ingår i: Journal of Applied Polymer Science. - : John Wiley & Sons. - 0021-8995 .- 1097-4628. ; 130:6, s. 4219-4228
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Tidskriftsartikel (refereegranskat)abstract
- The hydrolytic degradation and corresponding content release of capsules made of poly(d,l-lactic-co-glycolic acid) (PLGA) strongly depends on the composition and material properties of the initially applied copolymer. Consecutive or simultaneous release from capsule batches of combinable material compositions, therefore, offers high control over the bioavailability of an encapsulated drug. The keynote of this study was the creation of a superordinated database that addressed the correlation between the release kinetics of filling agents with different molecular weights from PLGA capsules of alternating composition. Fluorescein isothiocyanate (FITC)–dextran (with molecular weights of 4, 40, and 2000 kDa) was chosen as a model analyte, whereas the copolymers were taken from various 50:50 PLGA, 75:25 PLGA, and polylactide blends. With reference to recent publications, the capsule properties, such as the size, morphology, and encapsulation efficiency, were further modified during production. Hence, uniform microdisperse and polydisperse submicrometer nanocapsules were prepared by two different water-in-oil-in-water emulsification techniques, and additional effects on the size and morphology were achieved by capsule solidification in two different sodium salt buffers. The qualitative and quantitative examination of the physical capsule properties was performed by confocal laser scanning microscopy, scanning electron microscopy, and Coulter counting techniques to evaluate the capsule size distribution and the morphological appearance of the different batches. The corresponding agent release was quantified by fluorescence measurement of the FITC–dextran in the incubation media and by the direct measurement of the capsule brightness via fluorescence microscopy. In summary, the observed agent release showed a highly controllable flexibility depending on the PLGA blends, preparation methods, and molecular weight of the used filling substances
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