Koska

The life of Marc Koska changed the day he read that HIV would spread via unsafe injections like wildfire and he decided to do something about it. That was back in '84. It seemed to him that if injections were the cause, then the spread was preventable.  Today his invention, a low-cost non-reusable syringe, is being widely used. And, more importantly, his campaign to raise public awareness about the dangers of reusing syringes have even led India to change national policy.

"The quest was to develop a syringe that could be made of the same materials... tooling and assembly equipment and used in exactly the same way as a conventional syringe – but with one minor, negligible cost modification that would make re-use impossible. The K1 was the result. And today, 17 years later, literally millions are used every week. Once only, so that every injection with a K1 syringe is sterile and safe". 

If you want to see the syringe, watch this video.