Sharif Digital Repository

For designing a unit operation, knowledge about physical properties is essential. This is attained either by direct measurement, which needs spending time and cost or, using proposed correlations. This project is subjected to theoretical analysis of viscosity as the most important rheological property of dilute suspensions of microgels, or in other words colloidal suspensions of porous spheres. They are applied in drug delivery, enhanced oil recovery, synthesis of catalyst and adsorption of heavy metal ions from aqueous systems for water purification purposes. In dilute suspensions particles are faraway from each other and there is no interaction between them therefore, it is better to... 

Due to the increasing need of use of drugs and insufficient efficiency of conventional methods, drug delivery systems has gathered a lot of interests. There are different systems existing for controlled drug delivery, among which is implementation of hydrogel microparticles (microgels) as carriers with high potential. The most important factor in these systems is size distribution of drug-carrying microgels and a narrow size distribution leads to a controlled and suitable release. Due to unique characteristics of microfluidic systems, significant focus has been placed on them nowadays for production of microgels with suitable morphology and narrow size distribution. Therefore, in this study... 

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... 

The goal of tissue engineering is the restoration of a tissue function based on combination of cells, scaffolds, and biological signals in an engineered structure. The best way to develop this issue is mimicking the body and host tissues. In the present thesis, it was tried to improve cartilage tissue regeneration from two aspects. In the first part, an injectable hydrogel based on hyaluronic acid (HA) biomaterial was developed which was incorporated with platelet lysate (PL), as an autologous source of growth factors. The human mesenchymal stem cells (hMSCs) were encapsulated in the hydrogel and the effects of PL on the cell attachment, viability and differentiation toward chondrocytes were... 

Wrinkles on the skin are among the most common effects of aging, which are associated with a decrease in the concentration of fibroblast cells and the breakdown of collagen and elastin chains. Youthfulness and skin beauty are important attributes of nature that are directly linked to human self-confidence, attracting numerous candidates each year for skin rejuvenation and restoration. Over the years, several non-invasive methods have been introduced to address wrinkles and increase the volume of subcutaneous tissue, with subdermal fillers emerging as an effective and safe approach commonly used in aesthetic clinics. Commercial fillers are categorized based on factors such as the base... 

Microgels, three-dimensional networks belonging to the family of smart materials, exhibit significant structural changes in response to external stimuli such as temperature. The rapid deformation of microgels upon thermal stimulation makes them a promising alternative for various mechanisms. Despite the similarities between hydrogels and microgels, many of their properties differ. Moreover, the Flory-Rehner model, typically used to describe the swelling behavior of temperature-sensitive hydrogels, only provides a qualitative description of microgel swelling. Nevertheless, previous numerical models of microgels have largely been based on the assumption that their behavior mirrors that of... 

The growing global demographic and the growing rate of osteoporosis provide the definitive rationale for the development of effective methods for the treatment of osteoporotic defects of bone. These methods should not only compensate for ongoing injuries but should also manipulate the inherent disease processes to enhance the effectiveness of treatment. Therefore, the present study attempts to develop bioactive nanocomposite hydrogels through two different modalities—microgels and injectable bulk hydrogels—for the purpose of delivering alendronate (ALN) as a treatment approach for osteoporotic fractures. During the first phase of the research, gelatin-containing nanocomposite microgels...