Due to a combination of academic interests including nano-fabrication, quantum physics and computer science; I began researching situations where quantum effects are used to interface with biological systems. It was down this line of inquiry I came across a research paper focused developing a novel form of pacemaker utilising light and microelectronics. Currently a pacemaker is a capacitor that discharges its electrical current to the heart. This leads to altering the pace of the hearts beating. The device also uses electricity to monitor the heart’s beating.  

The widespread adoption of pacemakers has saved an enormous number of lives. This is due to a multitude of heart conditions affecting the rhythmic beating of the heart. 50,000 people are fitted with a pacemaker every year in the UK. The first internal pacemaker was implanted in the UK in the 1960s. The first pacemakers were traumatic to implant and difficult to live with but subsequent advances combining the physics of the devices with the surgical methods used has led to the standard pacemaker being the size of a match box being implanted under local anaesthesia.

The increasing capability of microelectronics especially is allowing more in vivo studies of complete pacemaker devices in rodents. This has the potential to allow more novel technologies to be trialled. 

Researchers at the university of Arizona have developed a pacemaker that has a flower shape and uses light to stimulate the heart. Optogenetic stimulation utilizes light photons to activate excitable tissue. The circuitry integrated into the device also has the capacity to be loaded with machine learning algorithms, these would be especially useful in this kind of device as electrical sensing can be used simultaneously with photo stimulation to continually monitor the hearts beating. The device could then alter the timing of its stimulation to avoid latency that would reduce the performance of the heart. Another reason electrical stimulation may not be the optimum solution is that it causes damage to the stimulation site and is not specific to the cells that need to be stimulated, causing discomfort (although most users stop feeling the pulsing). 

This research is being done in a major part to the miniaturization of the pacemaker devices allowing trials on rodents that could not be achieved before.  

The device used an array of 9 micro-LEDs. And 8 22 micro-Farad Capacitors in parallel to achieve desired capacitance. It was powered by magnetic resonant coupling; this allowed the subjects to move freely within the magnetic field. The device used infra-red report data back wirelessly.  

If a form of this device makes it to human trials, it will not just have to demonstrate the effectiveness and safety of the system. There is also more scope for things to go wrong both within the device and when it interacts with external magnetic fields, as the system will present more potential points of failure. The more complicated the devices are electronically the more maintenance will be required. The electronics would more than likely need to be hard coded as a strong enough magnetic field would totally wipe many forms of non-volatile storage. The use of micro-LEDs also poses physical challenges due to the proximity required to the target cells of complex electronics as opposed to an electrode feeding from a device implanted next to the heart. 

A pacemaker is much more critical to a person’s moment to moment survival than other more periphery devices such as a replacement pancreas. So, there must be some certainty that the device equals or surpasses the abilities of the current pacemakers in use in its most basic objective of long-term patient survival.