MUSE Imaging Accessory Using Frustrated Total Internal Reflection

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Solution Overview

Problem

Current smartphone microscope designs face challenges in implementing Microscopy with Ultraviolet Surface Excitation (MUSE) imaging due to limited clearance between the sample and the objective lens, which prevents conventional Type-C ultraviolet (UVC) LEDs from fitting, and the bulkiness and cost of multicolor fluorescent microscopy setups.

Innovation Solution

A compact external accessory for mobile device microscopes is developed, utilizing frustrated total internal reflection (FTIR) to deliver UVC light between the microscope objective and the sample, allowing for high-resolution MUSE imaging with a UVC-transparent optical window/sample holder as the total internal reflection waveguide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional Type-C ultraviolet (UVC) LEDs are used for MUSE imaging, then the imaging functionality is achieved, but the clearance requirement between sample and objective lens is not met

Engineering Contradiction:

ImproveMUSE imaging functionalityVSAvoidclearance between sample and objective lens

Core Design Contradiction:

Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The patent delivers UVC light laterally through the objective lens rather than from below the sample. This dimensional change in light delivery direction allows the UVC source to be positioned in a different spatial arrangement, bypassing the clearance constraint between sample and objective lens while still achieving surface excitation for MUSE imaging

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces an optical element (such as a dichroic mirror or beam splitter) as an intermediary to redirect UVC light from a top-mounted source through the objective lens onto the sample. This intermediary component enables the UVC light path to be routed through the objective without requiring the LED to fit in the limited clearance space

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multicolor fluorescent microscopy setup is used, then imaging functionality is achieved, but the device becomes bulky and costly

Engineering Contradiction:

Improvefluorescent microscopy functionalityVSAvoidbulkiness and cost

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses a single UVC light source that can excite multiple fluorophores with different emission wavelengths. By selecting fluorophores that are all excited by UVC light, the system achieves multicolor imaging capability without requiring separate excitation sources, filters, or dichroic mirrors for each wavelength, thereby reducing device complexity and cost while maintaining imaging versatility

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the excitation wavelength parameter to UVC range, which has the advantage of being able to excite a broad spectrum of fluorophores. This parameter change allows a single UVC source to replace multiple visible light sources, simplifying the optical train while maintaining the ability to image multiple fluorescent labels simultaneously

Inventive Principle:

Principle #35Parameter changes

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

The solution enables high-resolution MUSE imaging with a mobile device microscope, overcoming the limitations of clearance and cost, while maintaining the convenience and portability of a smartphone-based system.

Implementation Method 1

exciting the one or more exogenous fluorophore and/or fluorescent probe within the sample with Type-C ultraviolet (UVC) light, produced by one or more light emitting diode (LED), having a center emission wavelength that causes emission by the one or more exogenous fluorophore and/or fluorescent probe

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 2

utilizing frustrated total internal reflection (FTIR) to deliver UVC light between the microscope objective and the sample, allowing for high-resolution MUSE imaging with a UVC-transparent optical window/sample holder as the total internal reflection waveguide

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS12281985B2Methods for microscopy with ultraviolet surface excitation (MUSE) imaging

Publication Date: 2025.04.22 CASE WESTERN RESERVE UNIV

AI summary

Described herein are methods for imaging a fluorescent bioassay (including a substrate, such as dispersed cellular sample, exposed to one or more exogenous fluorophore and/or fluorescent probe that accumulate in a structure of interest). The bioassay can be excited with Type-C ultraviolet (UVC) light produced by one or more light emitting diode (LED). The UVC can have a center wavelength that causes emission by the fluorescent bioassay. A digital optical device can collect a signal emitted from the fluorescent bioassay in response to the excitation. The methods relate in particular to Microscopy with Ultraviolet Surface Excitation (MUSE) imaging.