Sharif Digital Repository

Simulating the in-vivo environment of cancer tumors outside the body, can provide an appropriate condition for studying different key processes of the tumor micro-environment, such as aggregation, formation, growth, angiogenesis and metastasis of the cancer tumor cells, which can be useful in finding methods to cure, or at least control cancer. Every year, a variety of drugs are being developed to overcome cancer, all of which need to be experimented. Although, these drugs are now experimented on animals, and some human volunteers, the reaction of different patients’ cancer cells to different drugs may differ with the experimented animals, or even with other people. So, there needs to be a... 

In this manuscript, we designed and fabricated a novel integrated microfluidic Kidney Nephron-On-Chip. This chip is able to culture cell monolayers under various fluid shear stresses and divert osmotic pressure gradients while imposing four different concentrations of an injected drug on cells. The multi-layer platform consisting of two bubble-trappers to eliminate all unwanted bubbles from the system, a concentration gradient generator to generate four different concentrations of the injected drug, and a membrane-based cell culture chamber caple of providing renal cells with their in-vivo condition. Using colorimetric techniques, the bubble trapper ability was quantified at flow rates up to... 

According to statistics in 2012, around 14 million people worldwide have cancer, and 8 million have died that year, according to estimates, this number will increase to 21 millions new cancer case and 13 million mortality in 2030. Despite years of research on cancer, many questions about the mechanism of the spread of cancer in the body remain unanswered so far. The proposed models identify that the cells isolated from the primary tumor and transmit them to the circulatory system in the form of circulating tumor cells (CTCs) or in the form of clusters as responsible for the incidence of cancer. This process is called metastasis. Recent studies have reported the high potential of metastasis... 

Infertility is a growing global issue with significant psychological, economic, and social consequences, which among them, male factor infertility problems make up a considerable portion. The conventional methods of sperm separation inclusive of density-gradient centrifugation and swim-up with numerous problems contain DNA fragmentation and low yield, and both of the methods are not effective for samples with low sperm counts. Modern microfluidic systems are trying to improve this problem by increasing the quality of the isolated sperms. However, most of these systems rely solely on sperm motility as a separation mechanism, which is not a sufficient condition for the separated sperm to be... 

The process of separating cells from a laboratory sample, is a crucial step in biotechnology and medical science. Cells separation is important for various reasons, including the identification and treatment of diseases, as an example, separation of Circulating Tumor Cells (CTCs) from patient blood sample. CTCs are cells that shed from a tumor and diffuse into blood vessels. These cells are the starters of metastasis, the process in which cancer spreads in body, and are main reason of deaths caused by cancer. Extremely low percentages of target cells in the blood, clarify the importance of highly accurate and sensitive separation. Currently, conventional separation methods are of macro-order... 

Exosomes are a type of extracellular vesicles which are secreted by cells and could be found in all of human biofluids including blood. The size of exosomes is in the range of 30 – 150 nm. And they have a spherical structure with a phospholipid membrane. Exosomes are very important in academic research for the purpose of diagnostic and therapeutic practices because of their protein and nucleic acid contents.In this study a technological system was developed for isolation of circulating exosomes of human whole blood. This system consisted of a collection of microfluidic chips and protocols in order to extract a purified sample of exosomes from whole blood. First, a chip based on centrifugal... 

for decades Cancer has been one of the major causes of death universally. Though extensive efforts in developing new anticancer therapies, they face failures in clinical trials and curing the sick owing to time consuming and expensive preclinical models with poor predictions of drug responses in human. To address this challenge it is crucial to develop preclinical models mimicking the main aspects of a tumor that can provide effective prediction of therapeutic responses. Tumor on chip technology has appeared as a promising approach for providing effective cancer models and reliable preclinical predictions. In this project, collagen was first extracted as the main constituent of the tumor... 

Today, microfluidics, representing the precise and controlled displacement of small amounts of fluid, is one of the most efficient tools available in various research fields, including medicine. Digital microfluidics is one of the newest microfluidic methods, which is based on the theory of electrowetting on dielectric. According to this theory, by applying a voltage difference to a droplet of fluid on a hydrophobic surface, the droplet can be moved on that surface. Therefore, by fabricating a plate containing a number of electrodes completely isolated from each other and controlling them, small droplets of fluid can be moved on a hydrophobic surface. In this thesis, the electrodes of this... 

Microfluidic systems have the ability to produce microgels with uniform size distribution and spherical shape due to the laminar flow and better control of the flow rates. Spherical microgels with same size can be used as high-potential carriers for drug release. An important challenge in the production of these drug-carrying microgels is the simultaneous process of drug loading into microgels and their production. The overall goal of this project was to produce drug-carrying microgels with uniform size distribution that show controlled drug release. To achieve this goal, various factors such as the type of polymer, the type of drug, the volume ratio of the polymer and the drug and the... 

Understanding biological systems requires extensive knowledge of individual parameters, and to study the processes of cell differentiation and cell behavior, a suitable environment must be created with the physiological conditions of the human body. For this purpose, with the knowledge of microfluidics, a microenvironment can be provided to study the behavior of cells on a small scale. The use of bone tissue model microfluidic chips is an alternative and new method in which it is possible to study the behavior of cells to differentiate into bone and to examine the toxicity of drugs, which in itself can help in the effective and successful treatment of these cases show. Therefore, in this... 

Microfluidic technology is a field of science that deals with the design, implementation, optimization, and testing of fluid systems in small dimensions. This technology has made significant progress in various fields in the last decade, especially in medical engineering. As an interdisciplinary scientific field, this growing technology has many applications in medicine, pharmaceuticals, chemistry, and electronic industries. One of the primary applications of microfluidic devices is the development of "lab-on-a-chip" systems as point-of-care diagnostic tools, such as rapid diagnosis during surgery. A microfluidic system includes various functional modules: sample preparation and fluid... 

Despite the extensive research conducted so far to treat cancer, this disease is still one of the main causes of death worldwide. The results of recent studies reveal the importance of the tumor microenvironment in the growth, proliferation, and invasion of the primary tumor. Most common models in cancer research, such as 2-dimensional in vitro models and xenografts, do not have sufficient ability to mimic the interaction of tumors with human stromal tissue. Therefore, the implementation of 3-dimensional in vitro models with the ability to replicate tumor microenvironments is essential. In this study, a microfluidic platform has been introduced to create parallel models of the tumor... 

Nowadays, we are witnesses of deaths caused by cancer in large statistical amounts. Vast number of investigations are conducted for anticancer drug evaluation on human and animal cells using traditional two-dimensional and three-dimensional culturing platforms. However, most of them are not successful due to the lack of in-vivo relevant microenvironment in these platforms. One of the best cancer in-vitro cultures is the tumor spheroid which is a spherical cellular aggregation. By culturing these tumor spheroids in a microfluidic chip, it is possible to mimic the in-vivo microenvironment elements such as nutrient and metabolite gradients. Here we present a microfluidic device fabricated using...