Adjustable Bioresorbable SiO2 Sol-Gel Method
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Solution Overview
Problem
Current methods for preparing sol-gel derived SiO2 do not provide versatile means for achieving tailored bioresorption rates, particularly lacking the ability to produce materials with very fast bioresorption rates.
Innovation Solution
A method involving the preparation of sol-gel derived SiO2 using a sol comprising water, an alkoxide or inorganic silicate, and a lower alcohol, with specific pH and molar ratios, and either spontaneous gelation at controlled temperatures or forced drying, allowing for the adjustment of bioresorption rates by varying the starting conditions and composition changes before gel formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional sol-gel methods are used with standard pH and composition ranges, then stable gel formation is achieved, but the bioresorption rate cannot be tailored to very fast rates
Solution Approach 1:
The patent applies parameter changes by systematically varying pH (from very acidic to basic), water-to-alkoxide ratio, and alcohol-to-alkoxide ratio to control the hydrolysis and condensation rates. These parameter adjustments enable tailoring of bioresorption rates from very fast to slow while maintaining reliable gel formation through controlled reaction kinetics
Solution Approach 2:
The patent employs preliminary action by adding biologically active agents to the sol before gelation occurs. This ensures uniform distribution of the active agents within the gel matrix before the network structure forms, allowing controlled release while maintaining gel stability
2Reliability
If heat treatment at elevated temperatures is applied to sol-gel derived SiO2, then material stability is improved, but bioresorption capability is reduced
Solution Approach 1:
The patent applies parameter changes by controlling the drying temperature parameter (≤50°C) to prevent crystallization and maintain the amorphous structure of SiO2. This low-temperature drying parameter preserves both material stability and bioresorption capability by avoiding the formation of stable crystalline phases that would resist dissolution
Solution Approach 2:
The patent inverts the conventional approach by skipping the high-temperature heat treatment step entirely. Instead of using heat to stabilize the material, the patent relies on controlled low-temperature drying to achieve the desired stable yet bioresorbable amorphous SiO2 structure, achieving stability without sacrificing bioresorption
3Productivity
If drying temperature is increased to accelerate solvent removal, then production time is reduced, but control over bioresorption rate is compromised
Solution Approach 1:
The patent applies parameter changes by optimizing the drying temperature parameter within a specific range (≤50°C) that balances drying efficiency with structural control. This parameter optimization enables adequate drying speed while maintaining precise control over the resulting bioresorption rate through controlled pore structure formation
Solution Approach 2:
The patent employs dynamics by allowing controlled evaporation of solvents during the drying process to create a porous structure. The dynamic solvent removal at controlled temperatures creates the desired pore architecture that governs bioresorption, achieving both reasonable productivity and precise rate control
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
This method enables the production of SiO2 monoliths, coatings, or particles with controlled bioresorption rates, including very fast dissolution rates, suitable for administering biologically active agents, enhancing the delivery of drugs and other agents by optimizing their release profiles.
Implementation Method 1
Sol-gel derived SiO2 is commonly prepared from alkoxides or inorganic silicates that via hydrolysis form a sol that contains either partly hydrolysed silica species or fully hydrolysed silicic acid
Implementation Method 2
Consequent condensation reactions of SiOH containing species lead to formation of larger silica species with increasing amount of siloxane bonds
Implementation Method 3
The gels that are dried at moderate temperature (at ≤50° C.) are called xerogels
Data Source
AI summary
A method for preparing a sol-gel derived SiO2 having a very fast bioresorption rate where a sol-gel derived SiO2 is prepared from a sol comprising water, an alkoxide or inorganic silicate and a lower alcohol using a mineral acid or a base as a catalyst and the sol is aged and dried. The method uses a pH from 1.5 to 2.5, a molar ratio of water to the alkoxide or inorganic silicate of 0.5 to 2.5, a molar ratio of alcohol to the alkoxide or inorganic silicate is ≥0.5; and the sol is either let to gel without induced changes of composition and without forced drying of the sol, or a change of composition is induced; and within a time of ≤30 minutes, from the induced change forced drying of the sol is carried out or initiated.