Bio-resorbable Polymer Microspheres for Controlled Resorption
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Solution Overview
Problem
Current biomaterials for implantation, such as gelatin sponges and dextran starch microspheres, face issues with variable resorption rates, loss of shape and resistance after hydration, and inability to control final volume after implantation, limiting their effectiveness for drug delivery and vascular occlusion.
Innovation Solution
Development of bio-resorbable and swellable polymer microspheres based on PLGA-, PEG-, and PLA-based block copolymers, which maintain sphericity upon swelling and have a controlled degradation rate, allowing for extended residency in tissues and controlled drug release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If gelatin sponges are used as biodegradable implants, then they can be impregnated with physiological saline and contrast media, but they lose their shape and resistance after hydration
Solution Approach 1:
The patent uses a composite polymer structure combining PEG (polyethylene glycol) chains with cross-linking agents to create a hydrogel that maintains both porosity for impregnation and structural integrity for shape retention. The cross-linked network prevents collapse while allowing fluid absorption.
Solution Approach 2:
The patent modifies the physical-chemical parameters of the polymer by controlling the degree of cross-linking, molecular weight of PEG chains, and composition ratios to achieve optimal balance between swelling capacity and shape retention. This allows the material to absorb fluids while maintaining structural stability.
2Reliability
If dextran starch microspheres are used for resorbable implants, then they provide temporary vascular occlusion, but resorption is fast with half life below 1 hour and cannot be accurately predicted
Solution Approach 1:
The patent controls resorption time by adjusting polymer composition parameters including PEG molecular weight, cross-linking density, and monomer ratios. These parameters can be precisely tuned during synthesis to achieve desired residence times ranging from hours to weeks, providing predictable and controllable resorption behavior.
Solution Approach 2:
The patent incorporates design feedback mechanisms where the polymer structure is engineered to respond predictably to physiological conditions. The cross-linked network degrades in a controlled manner based on enzymatic activity and hydrolysis rates, allowing accurate prediction of resorption timing based on input parameters during manufacturing.
3Ease of operation
If water-absorbent dry microspheres based on acrylic and PVA copolymers are used, then they can be mixed with physiological saline, but final size varies too much to allow for controlled final volume after implantation
Solution Approach 1:
The patent uses PEG-based polymers with controlled hydrophilicity and cross-linking parameters to achieve predictable swelling ratios. By adjusting the PEG chain length and cross-linking density, the final volume after hydration can be precisely controlled while maintaining ease of mixing with physiological fluids. The consistent hydrogel formation ensures reproducible final dimensions.
4Object-affected harmful factors
If dextran starch microspheres are used, then they are non-toxic and readily degradable, but they are available only in small sizes with diameters below 100 μm which does not allow targeted embolization
Solution Approach 1:
The patent controls microsphere size during the polymerization process by adjusting monomer concentration, cross-linking agent amount, and reaction conditions. This allows production of microspheres ranging from 100 μm to several millimeters while maintaining non-toxicity and degradability. The PEG-based polymer system enables size control without compromising biological compatibility.
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 polymer microspheres demonstrate prolonged residency in synovial tissue for weeks, enabling sustained drug delivery and controlled resorption, with minimal inflammatory response and adjustable resorption speed, making them suitable for embolization and therapeutic applications.
Implementation Method 1
swellable polymer microspheres... demonstrate prolonged residency in synovial tissue... controlled swelling
Implementation Method 2
PLGA-based block copolymers... controlled degradation rate... resorption speed
Implementation Method 3
cross-linked polymers... polymer cross-linked by bio-resorbable PLGA-, PEG- and/or PLA-based block copolymers
Data Source
AI summary
The present invention relates to a polymer obtained from the polymerization of: (i) at least one monomer of formula (I) (CH2═CR1)CO—K (I) wherein: K represents 0-Z or NH—Z, Z representing (CR2R3)m—CH3, (CH2—CH2—O)m—H, (CH2—CH2—O)m—CH3, (CH2)m—NR4R5 with m representing an integer from 1 to 30; R1, R2, R3, R4 and R5 independently represent H or a C1-C6 alkyl; and (ii) at least one bio-resorbable block copolymer cross-linker.