Next-generation devices will rely on 3-D interconnect technology and power “scavenging.”
Ed.: This is the seventh of an occasional series by the authors of the 2017 iNEMI Roadmap. This information is excerpted from the Roadmap, which is available from iNEMI (http://community.inemi.org/content.asp?contentid=51).
Medical electronics research is moving into two camps: one consisting of traditional diagnostic, monitoring and implantable devices, and the second of cross-biological and silicon integration. Monitoring and implantable research will continue to be active areas of research. In these types of devices, the implantable or wearable contains a small radio. This radio will signal a cellular or other RF device, which in turn will collect data or forward it to the caregiver or medical personnel. Other types of connectivity include near-field communications (NFC), where two to four inches’ proximity between receiver and antenna enable the transference of data. These types of devices and connectivity require material research to find a material that is suitable for implantation and will still permit the radio signal to penetrate the body and the packaging material to reach the receiver. Good examples of these types of devices are the Proteus Digital Health pill monitor systems and a glucose-sensing contact lens from Google.
There is always a need to enable longer life in implantable and wearable sensors, and researchers need to examine power delivery technology beyond traditional batteries such as scavenging and high-frequency inductive wireless powering. Power scavenging relies on the thermal energy of the patient’s body (up to 30μW/cm²), uses mechanical motion of the patient’s body (up to 10μW/cm²) or through-body wireless power transmission. Powering sensors in this manner extends the battery charging life and reduces the need for higher capacity batteries.
Alternatively, research into high-frequency power coupling (GHz range) as explored by the Poon research group at Stanford holds promise for dramatically smaller devices with ex vivo power sources. Biological and silicon integration is best explained as establishing the interconnection between the biologic device and the silicon. Examples:
These examples are the beginnings of the interconnection between the biological and electrical worlds. One can foresee the interaction of silicon devices with muscle tissue to reconstruct the neurological damage associated with spinal cord injury or muscular dystrophy. Continued focus in this research area is needed to make progress toward solving many of the crippling diseases that impact mankind.
In the medical products group, there is no greater cry for development than the issue of total stack integration. No single infrastructure is established such that data may go seamlessly from any invivo sensor to recording device to patient records to health information exchanges back to the clinicians, laboratories, government entities, and even consumers themselves. Even the movement of patient records from one section of a hospital to another may cross two or more systems without a compatible means of moving the data seamlessly and securely.
Interoperability among medical devices continues to be a development challenge. With new standards, such as the Bluetooth Medical Device Profile specification or those from the Continua Alliance that create hardware and software building blocks, users will expect interoperability sooner rather than later – such as USB ports on computers or bank ATMs throughout the world – as demand increases in the home and consumer medical device market. Backend networking and analytics will be challenging, with different demands at single-point solutions. The “analytic continuum,” along with other seamless expectations (e.g., security, connectivity, service software) will demand interoperability occur during an individual’s day – through work, retail, health, hospitality, and automotive ecosystems – with a personalized user experience.
An important general trend in medical device technology is the need to continue miniaturizing devices using 3-D interconnect technology. This need is particularly acute in implantables, where smaller devices can help reduce procedural complexity and improve patient outcomes. There is an ongoing proliferation of use-cases for implantable medical devices where small size and power efficiency improvements are mandatory. One example is cardiac pacemakers, where intra-cardiac, lead-less architectures are being deployed. These pacemakers can be five to 10 times smaller than models deployed in 2012, with sizes, including battery, of less than 1cm3.
Another example is the bio-monitor (implantable or external). Certain procedures, such as cardiac ablations to correct cardiac arrhythmias, cost $50,000 to $75,000 per procedure. These need to be repeated in many instances due to low procedural yields. As bio-monitors become smaller and more capable, government or private insurers are likely to demand the use of biometric monitoring to assess patient burden and procedural effectiveness with objective data prior to authorizing initial or repeat procedures of this nature. This will be enabled by small, long lifetime biomonitors. For technology development teams, it will mean an accelerated demand for smaller and more capable connected monitoring devices that can operate 24/7 for years.
Realization of these devices will require 3-D SiP/heterogenous packaging of all system functions, including digital control, mixed signal ASICs, memory, sensors (magnetic field, 3-D motion, blood pressure, oxygenation, etc.) and RF telemetry (MICS or low-power Bluetooth). Similar trends exist for other active implantable devices, such as cochlear implants, neurostimulators (for pain management or deep brain stimulation) and bio-sensors.
‘Artificial Skin’ and Other Challenges
Among the technological challenges and trends facing medical electronics are:
is a hardware design engineer for Abbott and chaired the Medical Product Emulator Group (PEG) of the 2017 Roadmap.