Dear,

According to me, the top colleges for biomedical in tamil nadu are:

• Bannari Amman Institute of Technology, [BIT] Coimbatore. 
• Anna University of Technology Madurai, [AUTM] Madurai. 
• Rajiv Gandhi College of Engineering, [RGCE] Kanchipuram. 
• Salem College of Engineering and Technology, [SCET] Salem.

You can visit their site for further updates like fees, placements etc.Also, you can get some other colleges on the following site:

https://engineering.careers360.com/colleges/list-of-biomedical-engineering-colleges-in-tamil-nadu

Hope this helps!