Non-Contact Liquid Jet Material Characterization for Viscoelastic Skin
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Solution Overview
Problem
Existing methods for measuring properties of viscoelastic materials like skin are invasive, non-local, and lack the frequency range to accurately represent 'fast' deformations relevant for needle-free injections, leading to potential inaccuracies in jet injection depth and dose delivery.
Innovation Solution
A method involving a liquid jet with a velocity of 2-150 m/s is used to deform a target area of the material, allowing for local, non-invasive, high-frequency measurements of mechanical properties such as strain, Young's modulus, and viscosity, while also determining anisotropy and rate-dependent responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If contact-based measurement methods (indentometers, mechanical probes) are used to measure skin properties, then measurement can be performed with existing devices, but the measurements cause irreversible deformations like bruising and the properties measured do not represent fast deformations relevant for needle-free injection
Solution Approach 1:
The patent replaces contact-based mechanical measurement systems with a non-contact optical measurement system. High-speed imaging captures surface deformation caused by needle-free jet injection, and this optical data is combined with a computational model to determine mechanical properties without physical contact during measurement, thereby avoiding bruising while still obtaining relevant dynamic properties
Solution Approach 2:
The patent changes the measurement parameter from static deformation (used in traditional indentometry) to dynamic surface deformation at high speeds. By measuring the transient surface deformation during fast jet injection and analyzing it through computational modeling, the system obtains mechanical properties relevant to needle-free injection without using contact-based mechanical probes
2Ease of operation
If non-local measurement methods are used to determine skin properties, then measurement can be performed without contact, but the measurements do not provide spatially resolved local properties needed for precise injection control
Solution Approach 1:
The patent adds the spatial dimension to non-contact measurement by using high-speed imaging to capture two-dimensional surface deformation patterns. The computational model processes this spatially resolved optical data to generate maps of mechanical properties (Young's modulus, viscosity) across the target area, providing both non-contact operation and local property determination
3Device complexity
If measurement methods with low frequency range are used, then measurement can be performed with simple equipment, but the measurements cannot capture fast deformations relevant for needle-free injection
Solution Approach 1:
The patent employs high-speed imaging operating at very high frame rates (thousands of frames per second) to capture the transient surface deformation. This high-frequency optical measurement, combined with computational modeling, enables determination of dynamic mechanical properties at the high deformation rates relevant for needle-free injection without requiring complex mechanical test equipment
Solution Approach 2:
The patent replaces mechanical testing equipment with optical measurement and computational modeling. Instead of using complex mechanical apparatus to impose and measure fast deformations, the system uses high-speed imaging to capture surface deformation during jet injection and computes the mechanical properties through a model, achieving high-speed measurement capability with relatively simple equipment
4Productivity
If jet injection is performed without accurate knowledge of skin properties, then injection can be performed quickly, but the injection depth and dose delivery become inaccurate and unsafe
Solution Approach 1:
The patent performs preliminary measurement of local skin mechanical properties using the non-contact optical method before executing the needle-free jet injection. The high-speed imaging and computational modeling provide accurate local property data (Young's modulus, viscosity, anisotropy) that are used to pre-calculate optimal injection parameters, ensuring both speed and accuracy in the subsequent injection process
Solution Approach 2:
The patent implements a feedback mechanism where the measured local mechanical properties are used to adjust and optimize injection parameters. The system continuously monitors skin properties and uses this information to control jet injection parameters (pressure, duration, angle), creating a closed-loop system that ensures accurate depth control and safe dose delivery while maintaining high injection speed
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
This method enables efficient, continuous, and spatially resolved measurements of viscoelastic properties, improving the accuracy of needle-free injections by tuning the jet properties to the local material characteristics, thus enhancing both precision and safety.
Implementation Method 1
providing a liquid jet to a target area of the material... detecting a deformation of the material in the target area
Data Source
AI summary
The invention provides a method for determining a property of a target area of a material, wherein the target area has a size selected from the range of 100 μm2-100 mm2, wherein the method comprises: an exposure stage comprising providing a liquid jet to the target area, wherein the liquid jet has a jet velocity selected from the range of 2-150 m/s; a measurement stage comprising detecting a deformation of the material in the target area and providing a related signal; and an analysis stage comprising determining the property of the target area based on the related signal.