1. Nanotechnology Research Center (NTRC), The British University in Egypt (BUE), El-Shorouk City, Suez Desert Road, Cairo 11837, P.O. Box 43, Egypt
2. Chemistry Department, Faculty of Science, Benha University, Benha 13518, Egypt
3. Biophysics Group, Physics Department, Faculty of Science, Ain Shams University, Khalifa El-Maamon Street, 11566 Cairo, Egypt