The correct answer is (b) Portable biosensor
The best explanation: Portable biosensor measures as low as 5 ng of cocaine in urine samples in 45 seconds. If cocaine is present in the urine, it is displaced with fluorescent molecules which will elute out, when urine passes through the column. ELISA techniques when combined with biosensors, form immunosensor which increase their range, speed and sensitivity. Surface Plasmon Resonance biosensor measures protein interaction in real time without any labelling technique. Thyroxine measuring biosensor is used to detect Graves’ disease.