Expanded PTFE Monofilament Suture with Color Patterns
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Solution Overview
Problem
Existing surgical sutures face challenges in achieving high tensile strength, cost-effectiveness, and visual differentiation, with braided structures offering low tensile strength and moisture retention issues, while chemical knot formation methods lack high-strength suture production and color pattern implementation.
Innovation Solution
A method for producing an expanded polytetrafluoroethylene (PTFE) monofilament suture involving forming a paste with a hydrocarbon solvent, curing, extruding, expanding, stretching, and sintering, with multiple PTFE materials of different colors to create a high-strength suture with visual recognition properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a braided suture structure is used, then visual differentiation and tissue handling are improved, but tensile strength decreases and moisture retention increases
Solution Approach 1:
The suture is divided into multiple filaments (e.g., 7 filaments) twisted together to form a braided structure. This segmentation allows visual differentiation through color coding of individual filaments while maintaining structural integrity and tensile strength through the collective arrangement of all filaments.
Solution Approach 2:
Different filaments within the braid are assigned different colors or surface properties at specific locations. This local quality variation enables visual identification of filament orientation and braiding pattern without compromising the overall tensile strength of the suture construct.
2Ease of manufacture
If a braided suture structure is used, then visual differentiation is improved, but moisture retention increases
Solution Approach 1:
The harmful interstices between braided fibers that trap moisture are eliminated by using a monofilament construction with circumferential grooves or ridges instead. This extraction of the problematic braided structure removes the moisture retention issue while preserving visual differentiation through surface features.
3Reliability
If chemical knot formation is implemented, then knot security is improved, but manufacturing complexity increases
Solution Approach 1:
Chemical bonding mechanisms are replaced with mechanical knot-securing features such as circumferential grooves, ridges, or notches on the monofilament surface. These mechanical features physically lock the knot in place without requiring chemical reactions, simplifying manufacturing while maintaining knot security.
4Ease of manufacture
If multiple processing steps (etching, dyeing) are applied to achieve color, then visual recognition is improved, but manufacturing cost and complexity increase
Solution Approach 1:
Color pigments or fluorescent markers are incorporated into the PTFE material during the initial extrusion process rather than applying dyes after etching. This preliminary action integrates coloring into the base material formation, eliminating separate etching and dyeing steps while achieving durable visual recognition.
Solution Approach 2:
Multiple functions (structural formation and color application) are merged into a single extrusion process. The PTFE filament is extruded with embedded pigments or fluorescent compounds, combining the structural manufacturing and visual identification features into one integrated step.
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 resulting suture exhibits high tensile strength, low cost, and enhanced visual recognition through color patterns, addressing the limitations of existing sutures by providing improved handling and visibility.
Implementation Method 1
curing the first paste by exposing the first paste to a first temperature for a first time duration
Implementation Method 2
expanding the green monofilament by exposing the green monofilament to a second temperature for a second time duration
Implementation Method 3
sintering the green monofilament after the stretching the green monofilament
Data Source
AI summary
A method for making an expanded, and optionally multi-component and/or colored PTFE monofilament is disclosed. The method includes forming a first paste by mixing a PTFE powder with a hydrocarbon solvent; forming an extrusion preform by pressing the first paste into a form; curing the extrusion preform by exposing the extrusion preform to a first temperature for a first time duration; forming a green monofilament by extruding the first paste through a die; expanding the green monofilament by exposing the green monofilament to a second temperature for a second time duration, the second time duration occurring after the first time duration; stretching the green monofilament substantially along a longitudinal axis of the green monofilament, the stretching the green monofilament occurring after the expanding the green monofilament; and sintering the green monofilament after the stretching the green monofilament.