## 4 Biosensors in the Field of Healthcare
### Smart Implantable Devices for Non-CVD Diseases  
Implantable biosensors will have a multiplicity of roles in the human body. Their applications expand to address diseases such as neurological, ocular, and metabolic (glucose level) diseases to name a few applications. Smart medical devices such as StentrodeTM by Synchron (Figure 7A) is a stent with electrodes that can be inserted and deployed inside blood vessels in the brain. One such benefit of StentrodeTM is that it can record signals from deep sites in the brain and parse these to effector devices such as human computer interfaces (BCI). This technology allows patients to control devices using their mental thoughts via wireless technology; for example, digital typing [128]. In particular, the electrodes on the StentrodeTM sense the neurological activity and transmit signals through connecting leads to a processing and communication unit implanted in the chest. These signals are then decoded and sent to an external receiver to execute specific action. Recorded data are transmitted via Bluetooth wireless technology [129; 130]. NeuroPort arrays are another form of BCI built by Blackrock Neurot (Figure 7B) a start-up company. There device, consisting of 96 electrodes. The implantation of NeuroPort arrays on the brain enables sensing and recording neurons activity and thereby sends signals via connecting wire to an external device. These signals are then translated into commands and control objects such as a wheelchair or robotic hands [131; 132]. Using Bluetooth technology for data transmission in deep-body implants is not practical [133]. Thus, implementing such technology in smart stents and grafts is not feasible.  
The management of glaucoma requires the continuous monitoring of intraocular pressure. Korean researchers have been able to create smart contact lenses with an embedded sensor for the real-time monitoring of intraocular pressure (Figure 7C), and the wireless transmission of data via magnetic coupling to a smartphone app. Successfully, their approach showed promising results in both the animal model (rabbit) and the human model [134]. Furthermore, the integration of biosensors for the continuous monitoring of the blood glucose (Figure 7D) level introduced a paradigm shift in the management of dia  
Figure 6: Pacemaker development over time. (**A**) shows the first invented non-implantable pacemaker by the Canadian biomedical engineer [PERSON]; (**B**) shows the first implantable pacemaker implanted by cardiac surgeon [PERSON]; (**C**) illustrates the Medtronic implantable pacemaker, in addition to the leadless intracardiac MicroTM, which is more than 90% smaller than typical pacemakers; (**D**) represents the intracardiac NanostimTM pacemaker by Abbott (formerly St. Jude Medical) [117].  
betes. There are various commercially available devices include \"Dexcom\" and \"Freeslyte Libre\". Both devices transmit data wirelessly via Bluetooth to smartphone app [132].  
Figure 7: Applications of smart biomedical devices. (**A**) demonstrates one form of BCI, termed StentrodeTM by Synchron. It consists of electrodes built onto the stent’s struts, capable of sensing from within the brain (Panel A is sourced from Synchron). (**B**) BCI NeuroPortTM, which consists of 96 electrodes developed by Blackrock (from Blackrock website). (**C**) shows smart eye contact lenses for the continuous monitoring of intraocular pressure developed by a Korean research team [134]. (**D**) shows Freeslyte Libre for monitoring the glucose level in the blood. It enables continuous observation and displays results in a smartphone app [132].  
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