Abstract:
Optical measurement of physiological parameters with wearable devices often includes measuring signals in the presence of significant noise sources. These noise sources include, but are not limited to, noise associated with: variable optical coupling to skin or tissue, variations in tissue optical properties with time due to changes in humidity, temperature, hydration, variations in tissue optical properties between individuals, variable coupling of ambient light sources into detectors, and instrument and detector noise, including electrical noise, radio frequency or magnetic interference, or noise caused by mechanical movement of the detector or its components. The present disclosure includes devices and methods configured to produce representations of the raw data in which noise, broadly defined, is separated from the data of interest. The disclosed devices and methods may include subtracting or calibrating out these noise sources and other spurious fluctuations in wearable devices with optical sensors.
Abstract:
Systems and methods are provided for detecting the flow of blood or other fluids in biological tissue by illuminating the biological tissue with two or more beams of coherent light and detecting responsively emitted light. A difference in wavelength, coherence length, beam divergence, or some other property of the beams of illumination causes the beams to preferentially scatter from, be absorbed by, or otherwise interact with respective elements of the biological tissue. Flow properties in one or more regions of the biological tissue (e.g., a region with which both beams of light preferentially interact, a region with which only one of the beams preferentially interacts) could be determined based on detected responsively emitted light from the biological tissue. Variations in speckle patterns over time and/or space, Doppler shifts, or some other properties of the detected light could be used to determine the flow properties.
Abstract:
Wearable devices are described herein including at least two photodetectors and a mount configured to mount the at least two photodetectors to an external surface of a wearer. The at least two photodetectors are configured to detect alignment between the wearable device and a target on or in the body of the wearer (e.g., to detect the location of vasculature within the body of the wearer relative to the at least two photodetectors). Alignment of the at least two photodetectors relative to the target could enable detection of one or more physiological properties of the wearer. For example, the wearable device could include a sensor configured to detect a property of the target when the sensor is above the target, and alignment of the target relative to the at least two photodetectors could include the sensor being located above the target.
Abstract:
An imaging agent for detecting analytes in an environment includes functionalized nanodiamonds and functionalized magnetic particles that can selectively interact with an analyte. Each functionalized nanodiamond contains at least one color center configured emit light in response to illumination. At least one property of the light emitted by the color centers is related to the proximity of the functionalized magnetic particles to the color centers. This property can be detected to determine that the functionalized nanodiamonds are proximate to the functionalized magnetic particles, to determine that the functionalized nanodiamonds and the functionalized magnetic particles are interacting with the analyte, or other applications. Devices and methods for detecting properties of the analyte by interacting with the functionalized nanodiamonds and functionalized magnetic particles are also provided.
Abstract:
An imaging agent for detecting analytes in a biological environment includes functionalized, silicon vacancy center-containing nanodiamonds. Individual nanodiamonds of the imaging agent include at least one silicon vacancy center. The at least one silicon vacancy center can emit light having a wavelength in a narrow band in response to illumination having any wavelength in a wide range of wavelengths. The nanodiamonds are functionalized to selectively interact with an analyte of interest. The nanodiamonds can additionally include other color centers, and the imaging agent can include a plurality of sets of nanodiamonds having detectably unique ratios of silicon vacancy centers to other color centers. The silicon vacancy centers in the nanodiamonds can have a preferred orientation enabling orientation tracking of individual nanodiamonds or other applications. A method for detecting properties of the analyte of interest by interacting with the imaging agent is also provided.