Hydrolysed Starch Microspheres with Charged Ligands
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Solution Overview
Problem
Current biodegradable starch microspheres lack the ability to alter their biodegradability, affinity to biological systems, swelling rate, compressibility/elasticity, and selectivity of chemical interactions, which are essential for specific medical applications such as hemostasis, wound healing, and vascular embolization.
Innovation Solution
Development of biodegradable microspheres with cross-linked hydrolysed starch, where endogenous, charged ligands are coupled via a carboxylic ester bond, allowing for tailored properties such as controlled degradation, cell affinity, and interaction with biological components, enabling applications in hemostasis, wound healing, and vascular embolization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If biodegradable starch microspheres are used for temporary vascular occlusion and hemostasis, then they provide temporary vascular occlusion and hemostasis, but they lack the ability to alter their biodegradability, affinity to biological systems, swelling rate, compressibility/elasticity, and selectivity of chemical interactions
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of starch microspheres through controlled hydrolysis to create different degrees of polymer chain scission. This results in microspheres with varying molecular weights, degradation rates, and physical properties. By adjusting hydrolysis conditions (time, temperature, enzyme concentration), the patent produces a range of microspheres with tailored biodegradability, swelling rates, and mechanical properties, directly resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The patent creates composite material systems by combining hydrolyzed starch components with specific cross-linking agents and functional modifiers. These composite structures allow independent optimization of different properties: the starch matrix provides biodegradability, while cross-linking agents control structural integrity and degradation rate. This composite approach enables versatile property adjustment without proportionally increasing overall system complexity.
2Duration of action of moving object
If starch microspheres are degraded in vivo by plasma amylase into oligosaccharides, maltose and glucose, then they enter normal metabolism, but they cannot provide delayed biodegradability for extended healing support
Solution Approach 1:
The patent applies preliminary action by pre-modifying starch molecules through controlled hydrolysis and cross-linking before in vivo application. This pre-treatment creates a predetermined structural framework that controls the subsequent degradation kinetics. The cross-linking density and hydrolysis degree are adjusted in advance to ensure predictable degradation rates, transforming the unreliable natural degradation process into a controllable, time-dependent release mechanism for extended healing support.
Solution Approach 2:
The patent introduces dynamics by creating microspheres with time-dependent structural evolution. The cross-linked starch network dynamically changes over time as enzymes progressively degrade the structure, transitioning from an intact gel phase to a degraded state. This dynamic structural evolution allows the material to maintain structural integrity during the desired duration and then rapidly degrade, providing both predictable timing and reliability for extended healing applications.
3Reliability
If endogenous, charged ligands are coupled via carboxylic ester bond to hydrolysed starch, then the microspheres exhibit enhanced cell attachment and vascular occlusion capabilities, but the manufacturing process becomes more complex
Solution Approach 1:
The patent uses carboxylic ester bonds as intermediary linkages between the hydrolyzed starch matrix and endogenous charged ligands. This intermediary chemical bond provides stable yet controllable attachment, allowing ligands to be firmly anchored for reliable cell attachment while maintaining the ability to degrade under physiological conditions. The ester bond formation uses standard chemical conjugation methods, adding only moderate complexity to the manufacturing process while significantly enhancing biological performance.
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 modified microspheres exhibit enhanced biodegradability, cell attachment, and vascular occlusion capabilities, facilitating efficient hemostasis, wound healing, and vascular embolization by adjusting their properties to suit specific medical needs, including delayed biodegradability for extended healing support.
Implementation Method 1
endogenous, charged ligands are coupled via a carboxylic ester bond
Implementation Method 2
The starch microspheres are degraded in vivo by plasma amylase into oligosaccharides, maltose and eventually to glucose
Implementation Method 3
The starch microspheres are degraded in vivo by plasma amylase
Data Source
AI summary
Biodegradable microspheres having a diameter of 10-2000 μm having cross-linked hydrolysed starch onto which at least one type of ligand has been coupled via a carboxylic ester bond. The ligand shall be an endogenous, charged molecule with a molecular mass of less than 1000 Da having at least one additional carboxylic acid function in addition to the one utilised for coupling the ligand to the microsphere and/or at least one amine function. On average 0.05-1.5 ligands are coupled to each glucose moiety in the hydrolysed starch.