CORNERSTONE drives innovation for next-generation biosensors

CORNERSTONE drives innovation for next-generation biosensors  - blog post by Milan Milosevic, February 2022

“If you want to find the secrets of the Universe, think in terms of energy, frequency and vibration.” – Nikola Tesla 

 I really like this statement because it fosters creativity and pervades through various fields and disciplines. Nikola Tesla was one of the greatest inventors of all time. It is said that he could envision his inventions in his dreams. I am not sure about that, however, it is well known that if two or more objects share a common "frequency" or “wavelength”, remarkable things might happen. For example, a colossal suspension bridge made of steel may collapse under a wind that unexpectedly triggers a small vibration to a certain part of the bridge, matching its resonant frequency. Things are similar with biomolecules. For example, by matching the resonant frequency of the cancer cells or living microorganisms, it is possible to shatter cells into dozens of fragments thus curing various conditions and diseases. 

Traditionally, biosensing market was revolving around products for diagnosing the state of disease (e.g. glucose for diabetes), however, nowadays, an adult cares about the environment, and healthy lifestyle much more than before. Therefore, R&D industry needs to come up with new products and solutions to non-invasively, accurately, and affordably monitor various health parameters that will provide early warnings and diagnosis of disease (e.g. cancer, heart disease, antimicrobial resistance, infectious diseases).  

Recent developments in silicon photonics technology, together with advancements in signal processing, artificial intelligence, machine learning, and internet of things, may transform the world we live in, and bring to market various types of biosensors for monitoring the human body, pathogens, and food contaminants.   

Today’s optical technology typically requires large scale components that are bulky and sensitive to high-moisture environments. Silicon photonics technology provides package-level large scale integration of different optical components on the chip, increasing device functionality, and reducing production costs and device failure rates (~10s of devices per million), thus enabling the possibility for reliable, accurate, affordable, long-term biosensing and environmental monitoring.  

CORNERSTONE introduces a new Ge-on-Si platform to forge new advancements in sensing and healthcare industries 

The CORNERSTONE team has a long history of working in the area of mid-infrared silicon photonics, publishing the world’s first low loss waveguides and devices for sensing and biomedicine. The mid-infrared area is very exciting for diverse sensing applications because different gases and biomolecules strongly absorb light at different mid-infrared wavelengths (particularly between 8mm -12mm wavelength, called the “fingerprint region”). Therefore, our versatile platforms offer plethora of possibilities for building different photonic integrated circuits that could be used for real-time measurement of absorption spectra of analytes, antibodies, or enzymes, for example. 

For instance, the silicon nitride platform might be used for visible and near-infrared sensing, while the suspended silicon platform offers a much wider transparency range, up to 8mm wavelength. This is achieved by removing the lower silicon dioxide layer (BOX) that is very lossy beyond 3.6mm wavelength. Photonic integrated circuits based on the suspended silicon platform could be tailor engineered to support single mode and low loss waveguiding, and at the same time high evanescent mode field strength, which is ideal for sensing applications where we need strong interaction between the light and the analyte, thus measuring concentration or activity of biomarkers present in the sample. 

CORNERSTONE offers different material platforms and layer thicknesses, standard component libraries, bespoke and multi-project wafer services, allowing customers who do not possess expert knowledge in silicon photonics to easily build photonics integrated circuits, and bring their ideas to reality through CORNERSTONE. We have just launched a Ge-on-Si platform based on demand from users, extending the supported wavelength range into longer mid-infrared wavelengths up to 14mm.  


CORNERSTONE will help researchers to develop novel biosensors to monitor drugs, speed up cancer detection and reduce green-house effect of climate change 

Graham Reed, CORNERSTONE PI, has recently been awarded £5.8M EPSRC funding to "unleash the full potential of integrated mid-infrared photonics". This new project, called MISSION (Mid-Infrared Silicon Photonic Sensors for Healthcare and Environmental Monitoring), will be supported by the CORNERSTONE team, and will aim to demonstrate new solutions in three key areas: liquid biopsy for faster cancer detection, the monitoring of therapeutic drug levels and the measuring of greenhouse gas emissions from our oceans.  

"We will realise low cost, mass manufacturable devices and circuits for biomedical and environmental sensing; subsequently improve performance by on-chip integration with sources, detectors, microfluidic channels, and readout circuits; and build demonstrators to highlight the versatility of the technology in important application areas," MISSION states. 

By utilising the plethora of CORNERSTONE platforms, other researchers across the globe can target similarly lofty ambitions. 


CORNESTONE is very proud of remarkable customer service, and is planning to launch a “free test chip programme” to support knowledge exchange and provide new opportunities to researchers CORNERSTONE prides itself on the level of service and personal touch provided to our users. Every member of the team is ready to go above and beyond the call of duty to help users at every stage of their journey by providing expert advice and guidance. No license agreement is needed to access CORNERSTONE, and sign-up as well as design submission can be done in a few easy steps within minutes. We also take confidentiality and data-handling really seriously, only sharing our own designs which are available online. No project is too small for CORNERSTONE, and although we have worked with large companies and user sensitive data, we take a big pride that we always support novices in the area of silicon photonics, helping them at every stage of their journey. CORNERSTONE is always happy to experiment and try new things to benefit society and is the place where early stage R&D projects are developed, and proof-of-concept and prototyping demonstrated. 

Dr Andrew Sappey, Director of New Technology Development at OnPoint Digital Solutions, says: “We entered into an agreement with CORNERSTONE to produce 2 x 2 couplers for operation in the mid-infrared based on a suspended Silicon platform. To our knowledge, this represented the first time that such devices had been designed and produced. We ended up with multiple functioning devices close to the predicted performance. Given the sensitivity of producing devices based on a completely new platform, we were pleased regarding the disposition of IP and the care with which confidential information was handled. The interaction was simultaneously successful and enjoyable.” 

To advocate for the emerging applications and platforms in silicon photonics and support knowledge exchange, we are working on an exciting new programme to offer an additional test chip for free to our users. Watch this space and sign up to our newsletter for the latest updates and insider stories! 

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