Biotechnology is the use of living systems and organisms to develop or make useful products, or "any technological application that uses biological systems, living organisms or derivatives thereof, to make or modify products or processes for specific use.

Biomedical engineering is mainly concerned with the facts, theories and models describing biological and clinical phenomena, including other subjects such as physiology, virology, biochemistry, molecular biology and proteomics. It is the most widely applied in development of engineering solutions to both biological and clinical areas.

Both are the good options & have good scope in future but you need to do the struggle to make your space. It depends on your interest only.