Sensor Handheld Receiver

Microscale Medical Sensors Inserted Under Skin Powered Wirelessly by External Handheld Receiver:

by Anusha

Implantable electronic devices offer doctors to monitor certain condition of patients in a rapid and accurate way. But powering such devices becomes a challenging one:

Ø Circuit bulkier

Ø Eventually charging and replacing requires

Jia Hao Cheong at the A*STAR Institute for Microelectronics, Singapore, and his co-workers developed an alternative way for this by eliminating the usage of battery. Their miniature device is based on wireless power-transfer technology. The research team has developed a micro scale electronic sensor to monitor blood flow (i.e. blood pressure) through artificial blood vessels.

For instance, the grafts of the patients who have experiencing restricted blood supply should be checked periodically in order to avoid failure. So that Surgeons use these devices in grafts to bypass clogged blood vessel. But existing technique for this is very slow and costly.

To overcome that the researchers developed a prototype of device that could be incorporated inside the graft to monitor blood flow. Such an implant is powered by handheld external reader, which has an inductive coupling for wireless energy transfer.

 (This technology is similar to that of wireless charging mobile phones).

 The sensors are controlled by incoming energy power circuits based on silicon nanowires. This material is of piezoresistive: as the blood flows via the sensor the associated mechanical stress in the blood induce electrical resistance which is proportional to the pressure.

The main success of this device is the very limited power usage that is “12.6microwatts”. The device can be inserted inside the skin up to 50 millimeters deep.

Cheong says, "We have tested our system with 50-millimeter-thick tissue between the external coil and implantable coil, and it successfully extracted the pressure data from the implantable device,"

The next step of this project is to test it inside the graft of animal.