Apparatus and methods for detecting optical signals from implanted sensors
Inventors
Kintz, Gregory J. • McMillan, William A. • Wisniewski, Natalie A.
Assignees
Publication Number
US-11504035-B2
Publication Date
2022-11-22
Expiration Date
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
Some embodiments described herein relate to an apparatus including a light source configured to transmit an excitation optical signal to an implanted sensor and a detector configured to detect an analyte-dependent optical signal emitted from an implanted sensor. The apparatus can include a lens configured to focus at least a portion of the analyte-dependent optical signal onto the detector.
Core Innovation
Some embodiments relate to an apparatus including a light source configured to transmit an excitation optical signal to an implanted sensor and a detector configured to detect an analyte-dependent optical signal emitted from an implanted sensor, and the apparatus can include a lens configured to focus at least a portion of the analyte-dependent optical signal onto the detector. Some embodiments further relate to arrays of lenses and arrays of apertures arranged to restrict transmission of off-axis light to a detector, at least one layer of light control film arranged with the lens and aperture arrays to restrict light based on incidence angle, and at least one filter positioned to restrict transmission of light to the detector to wavelengths substantially within an emission wavelength range.
The background states a need for apparatus and methods for detecting optical signals from an implanted sensor so that a fluorescent sensor can be used without requiring electronics, batteries, antennae, or RF transmission hardware, and to address difficulty reading implanted fluorescent sensors because of low levels of fluorescence in the presence of high scatter due to dynamic changes in skin conditions. The patent describes that the skin is highly scattering and that scattering and absorption from biological components can dominate optical propagation, making accurate and consistent measurement of an analyte by monitoring an implantable sensor challenging in low-signal, high-scattering environments.
Some embodiments describe devices configured so that substantially only photons with wavelengths in excitation bands reach the target and substantially only photons with wavelengths in emission bands reach the detector by using optics, filters, lens arrays, aperture arrays, light control films, light-blocking elements, and filters, and by arranging light sources and detectors so that the ratio of detection surface area to excitation surface area can be at least 4:1. The described optical detection devices are presented as compact, wearable configurations operable to illuminate the implant, collect fluorescent emissions, normalize analyte-dependent signals with analyte-independent reference signals, and determine analyte values using stored or external processing.
Claims Coverage
The independent claim presents five main inventive features.
Excitation transmission through a first surface area
One or more light sources configured to transmit an excitation optical signal having an excitation wavelength through a first surface area of skin to an implanted sensor.
Detection through a different second surface area
One or more detectors configured to detect an analyte-dependent optical signal emitted from the implanted sensor through a second surface area of skin in response to the implanted sensor being illuminated by the excitation optical signal, the second surface area being different from the first surface area.
Array of lenses focusing mixed optical signal onto detector
An array of lenses, each lens configured to focus a mixed optical signal having a component with the excitation wavelength and a component with the emission wavelength towards onto a detector from the one or more detectors.
Light control film or aperture array inhibiting high-angle light
At least one of a light control film or an array of apertures configured to inhibit light having an angle of incidence greater than a predetermined angle of incidence from reaching the detector.
Angle-dependent filter between detectors and light control
A filter disposed between the one or more detectors and the at least one of the light control film or the array of apertures, the filter configured to allow the component with the emission wavelength to reach the detector, configured to attenuate the component with the excitation wavelength, and with the filter's effectiveness at attenuating the component with the excitation wavelength decreasing with increased angle of incidence.
The independent claim covers an optical detection apparatus combining separated excitation and detection surface areas, an array of lenses focusing mixed excitation/emission light onto detectors, angular restriction of incident light via light control films or aperture arrays, and an intervening filter whose attenuation of excitation wavelengths is angle dependent.
Stated Advantages
Suitable for providing accurate and consistent measurement of an analyte by monitoring an implantable sensor in low-signal, high-scattering environments.
Compact device that can accurately and consistently monitor an implanted sensor and be worn substantially continuously without substantially restricting movements or activities.
Allows continuous and/or automatic monitoring of an analyte and can provide a warning when the level of the analyte is at or near a threshold level.
Large detector-to-excitation surface area ratios and lateral detector positioning can improve detection of implant signals and improve detection accuracy.
Use of integrated CMOS detection can integrate detection, excitation, and digital filtering circuitry and reduce or eliminate the impact of ambient light.
Documented Applications
Monitoring analyte levels (e.g., glucose, lactate, oxygen) in tissue, including continuous glucose monitoring for persons with diabetes.
Wearable or skin-mounted readers such as wireless skin patch readers and patch configurations for subcutaneous implant monitoring.
Hand-held readers, bench-top instruments, imaging systems, smartphone attachments and applications that utilize the disclosed optics and algorithms.
Providing warnings of current or impending hyperglycemia or hypoglycemia based on analyte measurements from an implanted sensor.
Interested in licensing this patent?