טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentBargarum Julia
SubjectThe Effect of Nanoparticles on the Eye Lens as a Model
Biological Organ
DepartmentDepartment of Medicine
Supervisors Professor Abraham Reznick
Dr. Ahuva Dovrat
Dr. Orly Weinreb
Full Thesis textFull thesis text - English Version


Abstract

In the recent few years, nanotechnology is developing tremendously. It is a multidisciplinary field that????? involves design and engineering of objects on nanoscale. Because of the minute size, the fundamental properties of the matter are significantly changed. The newly acquired features have a great potential in different fields, such as optical devices, solar cells and biological imaging. Application of nanotechnology for treatment, diagnosis, prevention and control of biological systems is commonly known as nanomedicine. It makes the use of the nanomaterials, designed to interact with the body at the cellular and molecular scales, with a high degree of specificity. Fluorescent quantum dots (QD’s) are attractive alternatives for convenient fluorescent dyes in imaging techniques. Superparamagnetic NP’s can be used for drug delivering and for selective hyperthermia treatments. However, there are numerous dangers in using NP’s indiscriminately; QD’s are mainly based on toxic metals that can harm both the host and the environment.

This study deals with screening of the dose, time, structure-dependent toxicity of two Cd‑based QD’s: CdTe/AET and CdTe/CdSe/AET, and of superparamagnetic Fe2O3 NP’s, in the system of intact bovine eye lens as model of organ culture. It also aimed to establish the mechanism of action of CdTe/CdSe/AET (100 nM) in this system.

It was shown that bare CdTe/AET NP’s were deleterious for the eye lens even in low concentration of 4 nM. Coating with additional layer of CdSe improved NP’s biocompatibility, with a little damage observed in the low doses (1 nM-5 nM), but causing heavy biological damage in the high doses (25 nM-100 nM), during 12 days in organ culture. For the same period, superparamagnetic NP’s up to 50 mg/l were shown to have a little effect on the organ model. In addition, our findings demonstrated that the main biological mechanism of action of CdTe/CdSe/AET involved epithelial oxidative stress generation: increase in reactive oxygen species generation and decrease in anti-oxidative enzymatic activities (superoxide dismutase and glucose-6-phosphate dehydrogenase). These QD’s were shown also to impair the epithelial ionic balance.

Our system was demonstrated to be adequate for studying the toxicity and the mechanisms of action of the NP’s, and therefore it can be used for further studies in the field.