Bioabsorbable Polyester Medical Molded Articles for Body Followability
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Solution Overview
Problem
Medical molded articles made from bioabsorbable polyesters, such as polylactic acid and polyglycolic acid, lack sufficient mechanical strength and followability to the body, leading to potential displacement or tissue damage due to poor flexibility and hardness.
Innovation Solution
A medical molded article composed of a bioabsorbable polyester with a specific composition and structural design, including a polyester copolymer with a hydroxycarboxylic acid residue and lactone residue as main structural units, exhibiting an amount-of-work-holding rate of 55% or more, a Young's modulus of 10 MPa or less, and a tensile strength of 5 MPa or more, to enhance flexibility and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high molecular weight polymers and copolymers are developed to improve mechanical strength, then strength is improved, but followability to living body deteriorates due to increased hardness
Solution Approach 1:
The invention changes the chemical composition parameters of the polyester by controlling the molar ratio of hydroxycarboxylic acid units to lactone units (0.3 to 2.0), and by controlling the number average degree of polymerization (50 to 200). These parameter changes allow simultaneous achievement of adequate mechanical strength and improved followability to living body, resolving the contradiction between strength and adaptability.
Solution Approach 2:
The invention uses a copolymer composition combining hydroxycarboxylic acid units and lactone units in specific proportions. This composite material approach at the molecular level allows the polyester to achieve both mechanical strength from the hydroxycarboxylic acid segments and flexibility/followability from the lactone segments, resolving the contradiction between strength and adaptability.
2Reliability
If bioabsorbable polyester is used for medical molded articles, then biocompatibility is improved, but mechanical strength and followability deteriorate
Solution Approach 1:
The invention optimizes the parameters of the polyester structure, specifically the molar ratio of hydroxycarboxylic acid to lactone units (0.3 to 2.0) and the number average degree of polymerization (50 to 200). These parameter changes enable the bioabsorbable polyester to achieve both adequate mechanical strength and good followability while maintaining biocompatibility, thus resolving the contradiction between reliability and strength.
Data Source
AI summary
The present invention provides a medical molded article including a bioabsorbable polyester and having excellent followability to a living body, and the present invention is a medical molded article including a bioabsorbable polyester, the medical molded article having an amount-of-work-holding rate of 55% or more, the amount-of-work-holding rate defined as a rate of an amount of work generated finally by an operation that is repeated 10 times to an amount of work generated first by the operation, the operation in which a tensile stress is applied to the medical molded article in a direction of a maximum length of the medical molded article to generate a tensile strain of 100% with respect to an initial length.