Sharif Digital Repository

Cardiovascular disease is responsible for a majority of health problem in developing countries. Heart diseases are the leading cause of death in the United State with approximately 40% of the death occurs by heart failures and coronary artery defects. Myocardial infarction is one of the diseases that occurs by coronay artery blockage. Cardiac tissue engineering (CTE) is an emerging field that holds great promise towards the development of innovative treatment strategies for heart disease. There are two common scaffolds for CTE, electrospun fiber mats and hydrogels. Although fibers are known as 3D environment for cells, they actually act as a 2D surface, because of lack of cell infilteration.... 

In this work, wool keratin/polyethylene oxide (PEO) nanofibrous scaffolds were fabricated by electrospinning method. Bacterial cellulose nanofibrils (BCNFs) were embedded in the electrospun keratin/PEO nanofibers. Incorporation of BCNFs into the nanofibers enhances their hydrophilicity, mechanical properties and cell viability, adhesion and proliferation. Water contact angle of the nanofibers decreased from 126˚ to 83˚by addition of 1 wt % BCNFs. A thermogelling hydrogel based on carboxylated pluronic (Pl-COOH) and gum tragacanth (GT) was fabricated and polymer conjugation was confirmed by FTIR and H-NMR spectroscopy. Morphological and viscoelastic properties of GT-grafted Pl-COOH hydrogels... 

In this thesis, a new approach was developed to achieve mechanical and chemical resistant capillary microextraction (CME) in on-line combination with high performance liquid chromatography (HPLC) based on sol-gel technology. This thesis is divided into three chapters:
First chapter contains of two parts. Overcoming the lack of mechanical stability of the substrate of CME by replacing the fused silica by copper tubings was the main objective of the first part. Self-assembled monolayers technique was employed to functionalize the copper tube followed by chemical bonding of the sorbent on the inner surface of the copper tube by sol-gel technology. The prepared copper tube containing the... 

Hexavalent chromium ion (Cr+6) is a very toxic type of heavy metal in industrial effluents which is not biodegradable and accumulates in the human body that can cause genetic mutations and cancer. The aim of this project is to investigate the effect of wavelength and intensity of appropriate light on the reaction rate of photocatalytic reduction of Cr+6 ion to less toxic materials. In this project, we first designed and constructed a photocatalytic reactor to investigate the effect of wavelength and intensity of incident light on the reaction rate. The home-made photocatalytic reactor consisted of 120 LEDs in 12 different wavelengths, which has ability to control the intensity and... 

Tissue engineering has the potential to revolutionize our health care system. Conceptually, lost or malfunctioning tissues will be replaced by man-made biological substitutes to restore, maintain, or improve function. Tissue engineering has already shown great promise to contribute to treatments of a myriad of diseases including osteoarthritis, cancer, diabetes, skin burns, cardiovascular conditions and various traumatic injuries. Tissue engineering is a highly multidisciplinary discipline that demands integration of knowledge, tools and skills from biology, chemistry, engineering and medicine. Integrating nano- and microtechnologies into clinically sized implants represents a major... 

The main goal of this thesis was to develop μ-solid extraction techniques using electrspun nanofibers under the influence of magnetic field along with flow injection system. The thesis is divided into two sections:The first chapter deals with the use of magnetic field for improving μ-solid phase extraction efficiencies. After preparing the magnetic-based electrospun nanofibers (PBt/MNPs), sufficient numbers of disc from the prepared electrospun composite mat were cut and used as packing materials in a cartridge. The prepared system was coupled on-line to liquid chromatography for microextraction of selected drugs of furosemide, naproxene, diclofenac and clobetasol propionate. The homogeneity... 

The main purpose of this dissertation was to synthesize nanostructured adsorbents based on the sol–gel and electrospinning methods and implement them to the trace determination of the desired analytes from different matrices. In the first and second chapters, a summary of the sol–gel and electrospinning methods along with a glance on extraction methods are presented. Then, the implemented projects are presented in the consecutive chapters.In the first work, third chapter, silica nanofibers were successfully produced using electrospinning method. In this process, sol–gel was formed during electrospinning and then, the backbone polymer was removed by heating. To obtain a thin layer of silica...