Microneedle Waveguides for Wearable Deep-Tissue Sensing

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Solution Overview

Problem

Existing monitoring devices struggle to penetrate deep tissues for accurate biological signal collection due to attenuation and scattering by skin layers, while implantable devices pose infection risks.

Innovation Solution

A wearable apparatus with biocompatible microneedles configured as waveguides for sensing wave signals, enabling deep tissue data collection and wireless communication, using light or ultrasonic signals, with a control module for signal processing and transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If optical-based wearable devices are positioned above the skin surface, then the devices can be non-invasive and wearable, but they lack sufficient ability to penetrate through cutaneous and subcutaneous layers to collect adequately interpretable data from deeper regions

Engineering Contradiction:
Improvedeep tissue sensing capabilityVSAvoidattenuation and scattering by skin layers
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces microneedles as intermediary structures that penetrate the skin barrier to reach deep tissues. These microneedles serve as conduits for delivering optical sensors and waveguides directly to the target tissue, bypassing the attenuating and scattering effects of the skin layers. The microneedles act as a mediator between the external device and the deep tissue, enabling accurate sensing without requiring the entire optical path to traverse the skin.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the sensing system into multiple functional components: external wearable device, microneedle array, and deep tissue sensing region. The microneedles are individually positioned to reach specific deep tissue locations, allowing the system to divide the complex task of penetrating skin and sensing deep tissue into separate manageable stages. This segmentation enables precise targeting of deep tissues while keeping the external device simple and wearable.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If implantable devices are inserted at depth through invasive surgical procedures to bypass skin barriers, then deep tissue sensing can be achieved, but there is a cost of significant and/or non-negligible infection and inflammation risk

Engineering Contradiction:
Improvedeep tissue sensing capabilityVSAvoidinfection and inflammation risk
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the sensing function from the skin surface and places it at the deep tissue interface through microneedles. By taking out the sensing components and positioning them directly at the deep tissue location via the microneedle array, the system achieves deep tissue sensing without requiring extensive invasive surgery. The microneedles are minimally invasive compared to traditional surgical implantation, reducing the risk of infection and inflammation while still enabling access to deep tissues.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transitions from surface-level sensing to three-dimensional deep tissue sensing by inserting microneedles at angles that penetrate through the skin barrier. This dimensional change allows the sensing elements to be positioned at deep tissue depths while maintaining a minimal invasive entry point. The angled insertion and varying lengths of microneedles create a three-dimensional sensing architecture that reaches deep tissues without requiring extensive surgical exposure, thereby reducing infection risk.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If microneedles are used as waveguides to enhance penetration of sensing wave signals, then deep tissue data collection is enabled, but the device complexity increases

Engineering Contradiction:
Improvedeep tissue data collection capabilityVSAvoidmicroneedle array configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent designs the microneedles to serve multiple functions simultaneously: they act as mechanical penetrators to breach the skin barrier, as structural supports to position sensing elements, as optical waveguides to transmit signals to deep tissues, and as anchoring structures to secure the device. By making the microneedles multi-functional, the system reduces the need for separate components for each function, thereby managing device complexity while enabling deep tissue data collection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functions of the microneedle array with the optical sensing system. The microneedles are integrated with waveguides and sensing elements into a unified assembly that can be deployed as a single minimally invasive unit. This merging of components simplifies the overall device architecture compared to having separate systems for skin penetration, signal transmission, and data collection. The integrated design allows the microneedle array to function as both the delivery mechanism and the sensing platform.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables reliable and accurate deep tissue sensing without invasive procedures, providing continuous monitoring of physiological parameters like tissue oximetry and heart pulsation.

Implementation Method 1

the plurality of microneedles are configured to waveguide the wave signals into a deep tissue of the subject

Methodology Applied
Scientific EffectWaveguiding: Waveguide

Implementation Method 2

these layers are generally attenuating, light-scattering, and wave-absorbing

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 3

optical-based wearable devices positioned above and interfacing with a skin surface may lack sufficient ability to penetrate through cutaneous and subcutaneous layers

Methodology Applied
Scientific EffectOptical penetration: Absorption (EM radiation)

Implementation Method 4

one or more waveform generators configured to emit wave signals

Methodology Applied
Scientific EffectLight emission: Light

Implementation Method 5

one or more waveform generators configured to emit wave signals

Methodology Applied
Scientific EffectUltrasonic wave generation: Ultrasound

Implementation Method 6

detection of reflections thereof

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentUS20250331815A1Wearable apparatus for deep tissue sensing and digital automation of drug delivery
Publication Date: 2025.10.30 THE UNIV OF NORTH CAROLINA AT CHAPEL HILL
  • US20250331815A1 patent drawing
  • US20250331815A1 patent drawing
  • US20250331815A1 patent drawing

AI summary

Various example of the present disclosure provide sensing apparatuses configured for wearable and wireless use for deep tissue physiological monitoring. The sensing apparatuses may be embodied by a thin flexible patch configured to conform with a skin surface of a subject. A sensing apparatus may include a plurality of microneedles oriented to extend towards and penetrate into the subject to a shallow depth. The microneedles may be configured as waveguides for a given sensing modality (e.g., light, ultrasound), such that sensing wave signals propagate to deep tissues. For the sensing, the sensing apparatus includes waveform generators (e.g., light-emitted diodes) and waveform detectors (e.g., photodiodes). Machine learning models may be used to process and denoise sampled data from the waveform detectors and to generate accurate and reliable physiological measurements, including heart rate, respiratory rate, pulse intensity, respiratory intensity, blood oximetry, tissue oximetry, blood flow rate, and/or the like.