Swellable Adhesive Needles for Low-Force Tissue Bonding

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Solution Overview

Problem

Existing methods for achieving adhesion with soft tissues often require high mechanical force, can cause tissue damage, and may lead to inflammation or infection, and lack the ability to deliver therapeutic agents effectively.

Innovation Solution

Swellable adhesive needles, specifically double layer and single material microneedles, that penetrate tissues with low force, swell upon contact with liquid, mechanically interlock with the tissue, and can be removed without significant damage, providing strong adhesion and allowing for drug delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If chemical adhesives such as cyanoacrylate are used to achieve strong adhesion to tissues, then adhesion strength is improved, but tissue damage and inflammation occur due to reactive exothermic covalent cross-linking reaction

Engineering Contradiction:

Improveadhesion strengthVSAvoidtissue damage

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state of the adhesive from liquid chemical form to solid needle form, and changes the adhesion mechanism from chemical reaction to mechanical interlocking. The needles are inserted in a dry state and swell upon contact with tissue moisture, transforming from a rigid penetrable state to a swollen interlocking state, thereby avoiding exothermic chemical reactions that damage tissue

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the chemical adhesion system (cyanoacrylate cross-linking) with a mechanical adhesion system (needle insertion and swelling). The mechanical interlocking of swollen needles within tissue matrix provides strong adhesion without the harmful chemical reactions, effectively substituting chemical bonding with mechanical bonding

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If sutures and surgical staples based on mechanical fixation are used, then tissue damage is reduced, but adhesion strength is insufficient compared to chemical adhesives

Engineering Contradiction:

Improvetissue damageVSAvoidadhesion strength

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent applies local quality by creating concentrated mechanical interlocking zones at the needle-tissue interface. The swollen needles locally displace and interlock with tissue fibers, creating strong anchoring points without requiring widespread tissue disruption like sutures or staples. This localized mechanical engagement provides both strong adhesion and minimal tissue damage

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the adhesion function into multiple individual needles rather than using continuous mechanical fixation like sutures. Each needle acts as an independent mechanical anchor, and the collective effect of many segmented needles provides strong overall adhesion while distributing mechanical stress across multiple points, reducing localized tissue damage

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If conventional adhesives are applied to wet tissue surfaces, then adhesion is compromised, but needle adhesives maintain adhesion to both dry and wet surfaces

Engineering Contradiction:

Improveadhesion to wet and dry surfacesVSAvoidadhesion reliability on wet tissue

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs dynamics by designing needles that change their physical properties in response to environmental conditions. The needles are rigid and conical in their dry state for easy insertion, then dynamically transform by absorbing moisture and swelling upon contact with wet tissue. This dynamic state change allows the same needle structure to effectively adhere to both dry and wet surfaces without compromising reliability

Inventive Principle:

Principle #15Dynamics

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

These needles provide strong, reversible adhesion to tissues with minimal damage, enabling effective drug delivery and reducing the risk of infection, while maintaining adhesion to both dry and wet surfaces and dynamic tissues.

Implementation Method 1

The outer layer is configured to swell upon insertion of the needle into a substrate comprising a liquid

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

These bulbs locally displace the surrounding tissue as they swell, mechanically interlocking with the tissue and causing the needle adhesive to adhere strongly to the tissue

Methodology Applied

Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentUS11344711B2Swellable adhesive needles

Publication Date: 2022.05.31 THE BRIGHAM & WOMEN S HOSPITAL INC

AI summary

This disclosure relates to swellable needles that include a proximal end portion and a swellable distal end portion. Upon exposure to a liquid, the needles are configured to undergo a shape change from a first configuration in which the width of the needle is tapered from the proximal end portion to the distal end portion to a second configuration in which the distal end portion is more swollen than the proximal end portion. The swellable needles can be double layer swellable needles or single material swellable needles.