Wearable biosensors combine wearable devices and biosensors to monitor health metrics. Common types of wearable biosensors include Google's smart contact lens, which measures glucose levels in tears to help diabetics; the Q Sensor, which measures physiological signals like skin conductance to determine emotional excitement; wearable glucose sensors that monitor glucose levels through sweat or tears; and Samsung's Simband, which uses light beams and sensors in a wristband to measure metrics like heart rate and blood pressure in real time. Researchers are also developing temporary tattoos with biosensors that can monitor electrolyte and chemical levels in sweat to track weight and activity levels. Future biosensors may integrate sensors in floors, toothbrushes and other devices around the