Implantable Scaffold with Height-Referenced Geometric Landmarks

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Solution Overview

Problem

Current methods for testing biomaterials for implantation, such as those regulated by ISO 10993, require invasive procedures and large numbers of animal sacrifices, leading to high costs and ethical concerns due to the need for repeated surgical operations and histological analyses.

Innovation Solution

An implantable medical device is created using two-photon laser polymerization to form a three-dimensional matrix with reference means that allows for non-invasive, real-time observation of tissue growth and vascularization using a multiphoton fluorescence-excitation microscope, enabling objective and prolonged analysis without animal sacrifice.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional histological analysis methods are used to validate biomaterials according to ISO 10993 standards, then comprehensive tissue response data can be obtained, but large numbers of animals must be sacrificed and repeated invasive surgical operations are required

Engineering Contradiction:
Improvetissue response dataVSAvoidanimal suffering
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by implanting a reference scaffold with unique geometric features before the biomaterial testing begins. This reference scaffold remains in place throughout the observation period, enabling continuous non-invasive monitoring of tissue responses at the same location over time, thereby eliminating the need for repeated surgical operations and animal sacrifices while maintaining comprehensive data collection

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical invasive histological analysis system with an optical imaging system. By using optical microscopy to visualize tissue responses through the reference scaffold, the method substitutes physical tissue extraction and mechanical sectioning with non-invasive light-based observation, thereby reducing animal suffering while preserving measurement precision

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Duration of action of stationary object

If window chambers are implanted to enable intravital microscopy observation, then real-time in-vivo observation of tissue responses is possible, but repeated invasive surgical operations are required and the temporal duration is limited

Engineering Contradiction:
Improveobservation durationVSAvoidsurgical intervention
Core Design Contradiction:
Duration of action of stationary objectVSEase of operation

Solution Approach 1:

The reference scaffold is implanted preliminarily and remains in situ throughout the entire observation period, serving as a permanent landmark that enables continuous optical imaging without the need for repeated surgical access. This preliminary placement extends the observation duration indefinitely while eliminating subsequent invasive operations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The reference scaffold acts as an intermediary structure that facilitates optical imaging by providing a stable, identifiable reference frame within the tissue. This intermediary element enables long-term observation without requiring direct surgical access to the observation site, thereby extending duration while reducing surgical intervention

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of stationary object

If scaffolds are positioned within window chambers to reduce observation surface area, then observable volume increases, but unique identification of spatial regions at successive intervals becomes difficult

Engineering Contradiction:
Improveobservable volumeVSAvoidspatial identification
Core Design Contradiction:
Volume of stationary objectVSLoss of information

Solution Approach 1:

The reference scaffold incorporates unique geometric features at different spatial locations and heights, creating local quality variations that serve as identifiable landmarks. These distinct local characteristics enable precise spatial identification and tracking of specific regions throughout the observation period, preventing loss of spatial information while maintaining increased observable volume

Inventive Principle:
Principle #3Local quality

4Ease of operation

If two-photon laser polymerization is used to create the implantable device, then non-invasive real-time observation is enabled, but complex manufacturing process is required

Engineering Contradiction:
Improveobservation invasivenessVSAvoiddevice fabrication
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent uses two-photon laser polymerization to fabricate the reference scaffold, replacing traditional mechanical manufacturing methods. This additive manufacturing approach enables precise control of the scaffold's geometric features and internal structure, creating optically transparent or fluorescent components that facilitate non-invasive observation while maintaining manufacturing feasibility through computer-controlled laser processing

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution reduces development costs and animal suffering by allowing non-invasive, real-time monitoring of tissue responses to biomaterials, minimizing the need for surgical operations and animal sacrifice, while providing precise spatial identification and quantitative analysis of inflammatory responses.

Implementation Method 1

implantable medical device for enabling identification of a level referenced to a reference level in an implantable medical device using a multiphoton fluorescence-excitation microscope

Methodology Applied
Scientific EffectTwo-photon laser polymerization: Photopolymerisation

Implementation Method 2

said three-dimensional matrix comprises reference means designed to uniquely identify the height of each level from a pre-set reference, using a multiphoton fluorescence-excitation microscope

Methodology Applied
Scientific EffectMultiphoton fluorescence excitation: Fluorescence

Data Source

PatentEP3727136B1Implantable medical device
Publication Date: 2023.10.04 POLITECNICO DI MILANO
  • EP3727136B1 patent drawingFigure 1~2
  • EP3727136B1 patent drawingFigure 3~4
  • EP3727136B1 patent drawingFigure 5a~5b

AI summary

An implantable medical device obtained by means of two- photon laser polymerisation of a resin to form a three-dimensional matrix, wherein: said three-dimensional matrix comprises a number of levels distributed in height; and said three-dimensional matrix comprises reference means designed to uniquely identify the height of each level from a pre-set reference, by means of a multiphoton fluorescence-excitation microscope; said implantable medical device being characterised in that said reference means comprise a solid having a cross section that varies with height.