Tissue-Adhesive Sheet With Free Functional Groups
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Solution Overview
Problem
Existing tissue adhesives face challenges such as inadequate adhesion to biological tissues, premature curing, and the need for mechanical fasteners or external energy for bonding, which limits their effectiveness and practicality in surgical applications.
Innovation Solution
A preformed, cross-linked polymer matrix sheet with appendant functional groups, where a proportion of these groups are involved in cross-linking and the remainder are free to react with tissue surfaces, providing bioadhesive properties and eliminating the need for mechanical fasteners or external energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a viscous formulation is used to prevent spreading, then application precision is improved, but dispensability deteriorates
Solution Approach 1:
The adhesive is pre-formed as a solid sheet with controlled viscosity and cross-linking properties before application. The sheet is designed to maintain its shape and volume during storage and handling, then activates adhesion upon contact with tissue, eliminating the need for precise dispensing control while ensuring accurate application area coverage.
Solution Approach 2:
The adhesive formulation uses cross-linking agents and polymer composition to control viscosity and rheological properties. The sheet maintains appropriate consistency for handling while providing sufficient adhesion when applied to tissue, resolving the contradiction between viscosity for precision and viscosity for dispensability.
2Reliability
If a hydrated formulation is used for application, then adhesion to tissue is improved, but shelf-life deteriorates due to premature curing
Solution Approach 1:
The adhesive is pre-formed as a cross-linked sheet with controlled functionality. The cross-linking is designed to occur upon contact with tissue moisture rather than during storage, allowing the sheet to maintain stability and shelf-life while providing reliable adhesion when applied to hydrated tissue surfaces.
Solution Approach 2:
The sheet incorporates moisture-sensitive cross-linking mechanisms that require tissue contact to activate. This intermediary approach allows the adhesive to remain stable during storage and then activate adhesion properties when exposed to tissue moisture, preventing premature curing while ensuring reliable tissue bonding.
3Ease of operation
If a sheet is used to improve application precision, then ease of application is improved, but adhesion strength deteriorates due to detachment after hydration
Solution Approach 1:
The sheet is designed with controlled cross-linking density and polymer composition to maintain flexibility and conformability upon tissue contact. The cross-linking parameters are optimized to prevent detachment after hydration while preserving the sheet's ability to conform to tissue surfaces, thereby maintaining both ease of application and adhesion strength.
Solution Approach 2:
The adhesive sheet uses composite polymer formulations combining flexible matrix materials with cross-linking agents. This composite structure provides both the flexibility needed for easy application and the cross-linked strength required to maintain adhesion after hydration, resolving the contradiction between ease of application and adhesion strength.
4Reliability
If mechanical fasteners are used to reinforce adhesion, then adhesion reliability is improved, but device complexity and tissue damage increase
Solution Approach 1:
The adhesive sheet is designed to provide sufficient adhesion on its own without requiring mechanical fasteners. The cross-linked polymer matrix and functional group composition enable the sheet to bond reliably to tissue through chemical adhesion, eliminating the need for additional mechanical reinforcement and reducing both device complexity and tissue damage.
5Strength
If external energy is applied to initiate bonding, then adhesion strength is improved, but energy requirements and operational complexity increase
Solution Approach 1:
The adhesive sheet contains built-in cross-linking mechanisms that activate automatically upon contact with tissue moisture. The functional groups and cross-linking agents are designed to respond autonomously to tissue conditions, eliminating the need for external energy sources such as light or heat, thereby reducing energy requirements and operational complexity.
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 sheet exhibits strong and sustained adhesion to tissues, reducing the need for additional attachment methods and energy sources, while maintaining flexibility and a long shelf-life, making it suitable for various medical applications.
Implementation Method 1
a preformed, cross-linked polymer matrix sheet with appendant functional groups, where a proportion of these groups are involved in cross-linking and the remainder are free to react with tissue surfaces
Implementation Method 2
providing bioadhesive properties and eliminating the need for mechanical fasteners or external energy
Data Source
AI summary
This invention related to a tissue-adhesive sheet comprising a homogeneous, preformed and cross-linked matrix formed from one or more polymers, and having at least one surface that, in use, is exposed, at least one of said one or more polymers being a synthetic polymer and having appendant functional groups of a first form, cross-linking of said matrix being via a proportion of said functional groups of the first form, and the remainder of said functional groups of the first form being free. The sheet is particularly useful as a tissue adhesive and sealant, and is intended for topical application to internal and external surfaces of the body for therapeutic reasons. The invention further relates to sheets comprising a scaffold material, three-dimensional articles formed from similar material to that of the sheet and to implantable medical devices coated with such material.