Hari Sharma & Aruna Sharma were invited by Govt. of India to organize a Plenary Session on "Nanoscience & Diagnostic" in 99th Indian Science Congress on 5th January 2012 held in Bhubaneswar, KIT campus. Hari Sharma chaired the Plenary Session and gave the 1st Lecture. He told the august gathering that before nanoscience is developed for diagnostic or therapeutic purposes, the toxicological aspects of nanoparticles must be examined in details. Otherwise use of nanoparticles in medicine will not fulfill its basic purposes. The speech was very well appreciated as several questions were asked in a constructive manner. Especially student were very keen to know more about nano-neurotoxicity.