Degradable Silane Hybrid Polymers for Tissue Scaffolds
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Solution Overview
Problem
Current biodegradable polymers used in tissue engineering and medical applications have limitations such as high cost, non-adjustable degradation rates, limited mechanical properties, and potential for inflammatory reactions, and do not offer optimal cell adhesion or complete degradability, making them unsuitable for creating scaffolds for tissue regeneration and drug delivery systems.
Innovation Solution
Development of silanes with hydrocarbon chains interrupted by cleavable groups, allowing for the creation of biodegradable, organically modifiable silicic acid polycondensates that can be cross-linked and degraded under physiological conditions, providing mechanical properties similar to natural tissues and being suitable for cell colonization and sterilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If natural polymers are used for scaffolds, then cell adhesion and biocompatibility are improved, but cost increases and degradation rates cannot be adjusted
Solution Approach 1:
The invention creates hybrid polymers combining inorganic silicic acid polycondensates with organic polymer chains. The silane core provides structural integrity and tunable degradation, while organic modifiers (containing thiol, amine, or carboxyl groups) enable cell adhesion and biocompatibility. This composite approach achieves natural polymer-like biocompatibility with synthetic polymer controllability and lower cost.
Solution Approach 2:
The patent systematically varies parameters including silane substitution patterns (R1 groups with different hydrocarbon chain lengths), crosslinking density, and organic modifier composition to tune mechanical properties and degradation rates. By changing the ratio of hydrolyzable to non-hydrolyzable bonds and adjusting polymerization conditions, precise control over degradation kinetics is achieved without relying on natural polymers.
2Duration of action of stationary object
If biodegradable polymers like PLA and PGA are used, then degradation is achieved, but acidic degradation products cause inflammatory reactions and autocatalysis
Solution Approach 1:
The silicic acid polycondensate backbone is designed to degrade into small, water-soluble, non-toxic fragments through hydrolysis of siloxane bonds. Unlike PLA/PGA that produce persistent acidic monomers, the silane degradation products are rapidly dispersed and neutralized, eliminating the autocatalytic inflammation problem. The material is effectively 'disposable' at the molecular level, breaking down into harmless byproducts.
Solution Approach 2:
The patent converts the typically harmful acidic degradation environment into a beneficial controlled process by using buffers and selecting silane structures that degrade via neutral hydrolysis rather than acid-catalyzed autocatalysis. The degradation products themselves (silicic acid and organic fragments) are non-irritating, turning a potential harm into a safe, controlled degradation process that supports tissue regeneration.
3Reliability
If hybrid polymers with cleavable groups are synthesized, then complete biodegradability and water-soluble degradation products are achieved, but synthesis complexity increases
Solution Approach 1:
The hybrid polymer is segmented into distinct functional domains: a degradable silicic acid polycondensate core with cleavable bonds, and organic polymer chains containing thiol/amine/carboxyl groups for biocompatibility. The cleavable groups (ester, amide, disulfide, carbamate) are strategically placed at specific positions to ensure complete degradation into water-soluble fragments. This segmentation allows independent optimization of degradation and biocompatibility functions.
Solution Approach 2:
The patent employs systematic parameter variation in synthesis, including controlling hydrolysis-condensation conditions, adjusting silane to crosslinker ratios, and selecting different organic modifiers. These parameter changes enable tuning of degradation rate and completeness without fundamentally altering the synthesis pathway, making the complex process controllable and reproducible.
4Adaptability or versatility
If silanes with thiol and amino groups are used, then organically modifiable and cross-linkable properties are improved, but risk of unwanted side reactions increases
Solution Approach 1:
The silane structure acts as an intermediary between inorganic polycondensation and organic crosslinking reactions. The thiol and amino groups are protected or controlled during synthesis to prevent premature side reactions. Crosslinking is achieved through controlled addition reactions with dienophiles or carbonyl compounds, where the silane's oxygen-silicon bond serves as a stable linker that prevents unwanted interactions between thiol/amine groups and other functional groups during processing.
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 hybrid polymers are completely biodegradable, sterilizable, and exhibit mechanical properties comparable to natural tissues, making them suitable for scaffolds and implants, while avoiding the limitations of existing materials by controlling degradation and ensuring safety and efficacy in medical applications.
Implementation Method 1
the hydrocarbonaceous chain being separated from the next element by cleavable groups... wherein the cleavable groups are selected from ester, anhydride, amide, carbonate, carbamate, ketal, acetal, disulfide, imine, hydrazone and oxime groups
Implementation Method 2
The silanes can be inorganically condensed and/or organically linked via an addition reaction with compounds having C═C double bonds or rings
Implementation Method 3
The silanes can be inorganically condensed... to form organically modified silicic acid polycondensates
Implementation Method 4
the hydrocarbonaceous chain being separated from the next element by cleavable groups... wherein the remaining hydrocarbon chains are water-soluble when these groups are cleaved
Data Source
AI summary
The present invention concerns a silane of formula (1)R1aSIR4-a (1)wherethe group R1 or each of the groups R1 independentlyis bound to the silicon via an oxygen atom,comprises a straight or branched hydrocarbonaceous chain having one or more elements, wherein(a) each of the elements has not more than 8 consecutive carbon atoms, each of plural elements of the hydrocarbonaceous chain being separated from the next element by a cleavable group and/or(b) the elements have one or more cleavable groups and any hydrocarbonaceous chains remaining upon cleavage of said group(s) are water soluble,wherein said cleavable groups are selected from ester, anhydride, amide, carbonate, carbamate, ketal, acetal, disulfide, imine, hydrazone and oxime groups,has at least one thiol or a primary or secondary amino group,the group R or each of the groups R is independently a hydrolytically condensable group, anda is 1,2,3 or 4.The invention further relates to organically modified, polymerized silicic acid polycondensates which have been obtained by reaction and optionally subsequent hydrolytic condensation of such a silane or of silicic acid polycondensates therefrom with a bridging compound, which undergo an addition reaction with the at least one thiol or primary or secondary amino group of the radical R1 of the silane of the formula (1).