At the very beginning, I wish to express my sincere gratitude to my respected principal investigator Prof Dr. Niranjan Bhattacharya, former professor and HOD, Department of Regenerative Medicine and Translational Science, STM, Kolkata and co-investigator Prof. Dr Rita Ghosh, professor department of Biochemistry and Biophysics, university of Kalyani. I have received his and her valuable guidance at every moment in my long journey. Without the continuous support it would have been very difficult to complete the work.

I also express my sincere thanks to the respected Professor Dr. Sanjukta Bhattacharya, Professor (retired), Jadavpur University, for her continuous support during my research work and assistance in developing tools of research.