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07 Dec 2023
Wearable device said to add hydration and body temperature monitoring to regular features.
Rockley Photonics says it has begun sampling its latest “Bioptx” biosensing smart watch - incorporating a tiny short-wave infrared (SWIR) laser spectrophotometer - to strategic customers.
The UK-US firm, which emerged from Chapter 11 bankruptcy proceedings earlier this year, has built the wearable technology around a proprietary photonic integrated circuit (PIC) chipset.
Alongside the more conventional smart watch functions like heart rate and blood oxygenation monitoring, Bioptx is said to add hydration and body temperature measurements, through continuous collection of spectral data.
“The platform delivers real-time streaming of the SWIR-based biomarkers of body temperature and hydration, alongside the LED-based photoplethysmography (PPG) biomarkers of heart rate, heart rate variability, respiratory rate, and blood oxygen saturation,” announced the firm.
“Combined with the recently released Rockley Developer API, the platform creates a seamless solution for real-time monitoring of vital physiologic parameters.”
Rockley’s CEO and founder, Andrew Rickman, added: “We are thrilled to usher in the next generation of health monitoring with wearable laser-based technology.
“Rockley has created the full technology stack from the design of the PIC, which forms the miniature spectrophotometer, to the full wearable integration and novel biomarker delivery.”
Rickman added that the company has “significantly progressed” the SWIR-tissue measurement science and biomarker algorithms in recent studies, and is also working on non-invasive glucose sensing and cuffless blood pressure monitors.
ams Osram LED boosts signal-to-noise
In a related development, component maker ams Osram has released two new multi-LED packages that promise to improve the accuracy of PPG measurements by boosting signal-to-noise performance.
The more advanced version of the “SFH 7018” devices, which both incorporate a green, red, and infrared emitter, is said to offer twice the brightness of green light thanks to a multi-cavity design that separates the green LED path from the other emitters.
“The spacing and optical isolation ensure that the light sources are optimally placed relative to their photodiodes and reduce interference between the green light (for heart rate measurements) and the red light and infrared source (for blood oxygen saturation, or SpO2, measurements),” it stated.
“Furthermore, the green chip does not cause the red and infrared chips to fluoresce due to cross-excitation from the shorter wavelength.”
The end result should mean smart watches can provide more reliable measurements of heart rate and blood oxygen, which can be affected by skin color, stray light, water, or sweat.
Sergey Kudaev, a senior staff system architect at ams Osram, commented: ‘By using the new SFH 7018, manufacturers of wearable devices can dramatically improve the quality of the optical signals on which heart rate and blood oxygen measurements are based, making them more accurate and reliable in all operating conditions.
“The SFH 7018 can help to transform vital signs measurements into accurate and absolute determinations of heart rate, blood oxygen levels and even more advanced parameters, such as blood pressure.”
Vital signs
In one version of the SFH 7018, the red and IR LEDs are more than 40 per cent brighter than in the firm’s existing SFH 7016 package, and the green LED is 80 per cent brighter. In the more advanced version, the green LED is more than twice as bright, with ams Osram claiming that the brightness at each wavelength “greatly exceeds” that of its best-performing competitors.
“Since all vital signs monitoring devices face the challenge to detect little modulations of already small light signals, the result of scattering and absorption in tissue (depending on various factors), the amount of light emitted by the LEDs strongly affects system performance,” explains the firm.
“When more light is modulated by the blood flow and subsequently reaches the photodiode, signal quality improves, yielding higher accuracy and better repeatability of measurements. The SFH 7018 enables this superior performance by emitting more light into the body.”
Optical blood pressure app gets CE Mark
In another related development, the Swiss software startup Biospectal says that it has now received European CE MDR Class IIa medical device certification for its optical fingertip blood pressure monitoring app, which it calls “OptiBP”.
Said to be the first and only software app worldwide to receive the CE mark for measuring blood pressure on a smartphone, the development will see Biospectal OptiBP for Android become available initially in Switzerland, Germany, Austria, and France via Google Play from early 2024.
Developed with researchers at CSEM, the OptiBP app uses the built-in camera lens on a smartphone to record an individual’s blood flow via their fingertip. Many existing apps claim to offer that, but Biospectal’s proprietary algorithms and optical signal analysis methods are the first to gain CE Mark approval.
Its CEO and co-founder Eliott Jones said: “Our mission is to bring clinical capabilities to patients’ hands to empower them to keep track and manage their heart health. We envision a future where individuals can easily measure their blood pressure anytime, anywhere. That’s a real breakthrough.”
Masimo's FDA approval after Apple win
The various developments follow last month’s news that Masimo - the inventor of optical blood oxygen monitoring - had received US Food & Drug Administration (FDA) approval for over-the-counter and prescription use of its new “W1” smart watch.
“The FDA clearance expands the indications for the Masimo W1 in the US as a medical device for use by adults in hospitals, clinics, long-term care facilities, and in the home,” announced the firm at the time.
Masimo’s watch combines an integrated optical sensor and electrocardiogram (ECG) electrode pads that can be used to detect physiological signals, and is already being used by a number of hospitals in Europe and the Middle East.
The FDA decision came after a decision in October by the US International Trade Commission to issue an exclusion order on Apple smart watches incorporating Masimo’s patented light-based pulse oximetry technology in its products.
Scheduled to come into effect before the end of the year, the ruling followed years of litigation between Masimo and Apple over the optical technology involved in blood oxygen monitoring.
Masimo’s founder and CEO Joe Kiani said at the time: “Today’s ruling by the USITC sends a powerful message that even the world’s largest company is not above the law. This important determination is a strong validation of our efforts to hold Apple accountable for unlawfully misappropriating our patented technology.”
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