Sharif Digital Repository

The accurate assessment of biomarkers likes proteins, hormones or other biomolecules that amount of them changes with state of disease or level of treatment and gives diagnostic information is a difficult duty. In these samples, pathogens exist in small quantity compared to other background molecules. Therefore, appropriate sampling process for concentrating and separating pathogens from the matrix should be developed in order to provide rapid and accurate pathogen detection test. In this thesis design and fabrication of microfluidic biosensors based on the modified nanofibrous membranes were investigated and explained. PES nanofibrous membrane with carboxyl functional groups for covalent... 

The ability to diagnose a disease rapidly, non-invasively, with high confidence level and low cost can be of great importance in many ways such as 'detection and on-time conduction of remedial strategies. Hence It can reduce fatality rate and costs in the hygiene field. Currently some pathological diagnosis methods are not suitable considering their precision and costs and in addition to that, most of them are single-function and are developed for diagnosis of a particular disease and don't perform well in the case of multiple disease factors. Many diseases are caused by metabolic disorders and thus direct study of metabolic factors can provide us with a lot of evidence on the disease. One... 

The main purpose of this Ph.D. Thesis is to develop DNA-based biosensors using Label-free approaches applying simple, inexpensive and fast electrochemical techniques to measure the biological markers of cancer.In the first part, a simple protocol for detection of specific-sequence DNA is introduced. In this method carbon nanotube is used as a hybridization indicator. This label-free system provides the advantage of eliminating additional labeling procedure. As the signal enhances in the presence of MWCNT and decreases in the presence of target, the fabricated sensor is known as a signal-off device. The oxidation signal of Fe(CN)63-/4- is followed as an analytical signal to detect target... 

T lymphocytes or T cells are a type of white blood cell that play an important role in the immune system. Memory T cells are a subset of them that are able to reactivate when being re-exposed to the pathogen. Because of the properties of these cells, they are an attractive choice for immunotherapy. Initial memory subgroups were shown to be more persistently effective in immunotherapies. However little is known about development and differentiation of these subgroups. With the discovery of a new subset of T cells, called T memory stem cells (TSCM), They are considered to develop through four stages, naive T cells (TN), T memory stem cells (TSCM), central memory T cells (TCM) and effector... 

Today, medical science has come to the conclusion that the best time to start treating a disease is in its early stages. Therefore, the topic of early detection has been widely welcomed in scientific circles. Today, one of the safest methods for early detection in medicine is the study of biomarkers. These biomarkers include CTC, cfRNA, cfDNA, Exosome, etc. For instance, in the discussion of early cancer detection, the US Food and Drug Administration has so far identified two biomarkers, cfDNA and CTC, as the safest markers. The cfDNA marker is also widely used not only in the diagnosis of cancer, but also in the field of sex diagnosis and fetal Down syndrome in the first weeks of pregnancy.... 

Autism spectrum disorder (ASD) is a strong genetic perturbation that encompasses a wide range of clinical symptoms, including functional at different regions of the brain, repetitive behaviors, and interests, weaknesses in social relationships, some sensitivities to environmental factors and etc. Genetic complexity and the impact of environmental factors put the disease in the category of Level 1 complex developmental disorders.We proposed a pilot, combined, and highly effective structure to identify biomarkers in the autism spectrum disorder that could be extended to other diseases that have a similar genetic architecture with autism. We also develop a Gene-tissue interaction network to... 

Stroke is the second most frequent cause of death and the leading cause of disability in the world. Some effective drugs have been developed for ischemic stroke, while the golden time of use is three hours. Therefore, if stroke is diagnosed quickly, its side effects can be greatly avoided. However, it is not possible to use conventional diagnostic methods in many cases at a short time. In this work, S100β, MMP-9 and D-Dimer biomarkers were selected for rapid diagnosis of stroke based on previous studies.For this purpose, electrochemical immunosensors were developed with advantages such as low cost, ease of use, the possibility to automating the device, suitable sensitivity, reproducibility,... 

Cancer is the second leading cause of death in the world, with a high annual cost of treatment. As the cancer progresses, the cancer cells in the bloodstream metastasize to other parts of the body, causing the disease to spread throughout the patient's body and disrupt organ functions. sepration of cancer cells in the bloodstream inhibits the growth of cancer. Cancer cells differ from healthy cells in some features, such as size, electrical charge and polarization. These features can be used to seprate cancer cells from healthy cells.In this study, cell surface electrical charge was used as a biomarker to seprate cancer cells. By passing blood flow through a chanal and applying an electrical... 

Colorectal cancer (CRC) is one of the most common cause of cancer death worldwide. Identification of pivot genes in colorectal cancer can play an important role as biomarkers in predicting and early diagnosis and reducing the number of deaths caused by this disease. In this study, the aim of which is to discover pivot genes in colorectal cancer, six microarray datasets selected from the GEO database including 277 tumor tissue samples and 325 normal colon tissue samples. After data processing, differentially expressed genes and CRC-related genes were screened and 285 shared genes between them were identified for subsequent analysis. Based on 285 shared genes, the protein-protein interaction... 

In recent years, indirect methods of cancer detection that utilize changes in trace element levels in various parts of the body, such as hair and nails, have garnered significant attention from researchers.The primary objective of these methods is to identify alterations in trace element levels that serve as biological markers in the presence of disease. While direct examination of affected organs remains the gold standard for cancer diagnosis, it is often expensive, time-consuming, inconvenient, and associated with potential side effects. Therefore, if the effectiveness of this approach is validated, it could serve as a cost-effective, non-invasive, safe, and early diagnostic method in... 

The main approach in this thesis is the synthesis and identification of polyhedral oligomeric silsesquisans (POSS) and their modification with suitable functional groups to induce desired properties and use them as adsorbents or sensor. In the first work, POSSs were used as three-dimensional porous compounds with special properties as extractant phase in solid phase croextraction. Selective extraction of polar and non-polar molecules to particle size and functional groups on POSS. In this research, a threedimensional network of POSS including naphthalene diimide (POSS-NDI) and perylene diimide (POSS-PDI) as an extractant phase capable of absorbing volatile organic compounds was used to... 

Convenient medical diagnostics and treatments can replace conventional healthcare procedures because of their fast and profitable applications with reduced infection risk. Meanwhile, early diagnosis of cancer is leading research subject due to the high fatality rate of the disease and being a vital precursor in the treatment effectiveness. Electrochemical-based micro-biosensors are the best candidates for measuring biomarker concentrations in body fluids. To address this need, we used a simple fabrication approach to develop an effective immunosensor for the early detection of cancer, in particular prostate cancer. The carbon fibers, obtained from the electrospinning technique, decorate the...