As we continue to promote the economic and societal benefits of nanotechnology, advanced nanomanufacturing techniques are paving the road towards more integrated systems with increased functionality, scaled production platforms, and lower cost that will impact a broad range of industries. Nanomanufacturing has arguably had the largest impact in the area of flexible electronics and systems, affecting a range of product applications including displays, photovoltaics, lighting, energy storage, and printed electronics circuits. Perhaps the area of highest impact could be that in the area of devices interacting with the human body to extract specific biometrics for various purposes such as point-of-care health diagnostics, therapeutic treatment, or general activity monitoring. While these concepts have been around for decades, the key factors of technology push and market pull are now beginning to align in a manner that will accelerate and sustain the translational R&D necessary for these applications to grow. From a market pull perspective, the increasing cost of hospital and medical care combined with the growth of an aging population will necessitate in-home monitoring and out-patient care. Nanotechnology will most certainly provide the market push to meet these challenges.
In recent years, body-worn sensors have enacted a MEMS-based device approach that provides functionality, yet remains both invasive to the user and expensive for broad commercial implementation. These issues exist because the electronics and sensors are manufactured using batch-processing methods. Nanomanufacturing methods have emerged incorporating solution-based processes that enable a range of organic or inorganic nanomaterials to be assembled over large areas with precise control over composition and functionality. Incorporation of solution-based processes provides compatibility with low-temperature, flexible substrate materials, enables continuous processing via print or roll-to-roll manufacturing infrastructure, and can be integrated with conventional electronic circuit components. The latter remains a critical limitation as crystalline silicon electronics are far superior for computing and wireless telemetry than printed thin film transistors. That said, the ability for directed assembly of crystalline semiconductors, combined with advances in emerging materials such as carbon nanotubes, should give silicon electronics increasing competition from these critical components. In the mean time, silicon wafer thinning provides a proven method to obtain flexible silicon chip that can be integrated within a flexible system via advanced packaging capabilities.
With the availability of conformal sensor systems that can directly interface the body, technology advances are now able to realize complete systems, for example, that can monitor a range of external vital signs (EEG, EMG, ECG, body temperature), glucose, and blood oxygen, and store the information or transmit it wirelessly to a location where it may be analyzed by medical professionals. In addition, conformal electronic and microfluidic sensors are being adapted for invasive applications where blood or saliva samples need to be tested, and even for minimally invasive surgical tools, such as inflatable balloon catheters for cardiac electrophysiology (Kim, Lu, and others 2012). These advances will clearly provide a near term economic benefit as patient care can now shift to a condition-based paradigm, while expensive equipment used for routine monitoring can be replaced with lower cost, disposable components. Waiting in the wings is a broad consumer population enamored with mobile electronics that will provide the platform for fitness and activity monitoring products that will spin out of these technologies as cost and functionality targets are achieved. When we combine all of these applications and potential market opportunities, this certainly represents perhaps the killer app where nanomanufacturing will have the highest impact.
Kim DH, Lu K, Ghaffan R, Rogers JA. Inorganic semiconductor nanomaterials for flexible and stretchable bio-integrated electronics. 2012. NPG Asia Materials 4(e15). http://dx.doi.org/doi:10.1038/am.2012.27
Images reprinted by permission from Macmillan Publishers Ltd: Kim DH, Lu K, Ghaffan R, Rogers JA. Inorganic semiconductor nanomaterials for flexible and stretchable bio-integrated electronics. 2012. NPG Asia Materials 4(e15). http://dx.doi.org/doi:10.1038/am.2012.27