Resorbable Gelatin Microspheres for Temporary Vessel Occlusion
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Solution Overview
Problem
Current embolic materials used in medical procedures for blocking blood vessels are often permanent, which can be undesirable in certain clinical situations, and irregularly-shaped materials like Gelfoam can cause incomplete occlusion and unpredictable degradation.
Innovation Solution
Development of resorbable microspheres made from cross-linked gelatin with a spherical shape and calibrated size, which can be used to temporarily block blood flow and are designed to degrade within a specific in vivo time frame, ensuring complete occlusion and controlled degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If permanent embolic materials are used to block blood vessels, then complete and durable occlusion is achieved, but the ability to allow temporary blockage and subsequent healing is lost
Solution Approach 1:
The patent applies parameter changes by controlling the degradation rate of the embolic material through compositional parameters (gelatin concentration, cross-linking density) and physical parameters (microsphere size distribution). This allows the material to transition from an initial permanent-like occlusion state to a degraded state that permits recanalization, achieving both durable initial blockage and controlled temporary effect based on adjustable material parameters.
Solution Approach 2:
The embolic material is designed with dynamic properties, transitioning from a stable, occluding state initially to a degrading state over time. The cross-linked gelatin microspheres provide immediate occlusion but progressively degrade through enzymatic breakdown, allowing the blood vessel to recanalize. This dynamic behavior enables the same material to serve both permanent and temporary embolization needs depending on degradation rate control.
2Ease of operation
If irregularly-shaped embolic materials like Gelfoam are used, then ease of delivery is improved, but complete occlusion and predictable degradation are compromised
Solution Approach 1:
The patent employs spheroidality by using spherical microspheres instead of irregular particles. The spherical shape provides uniform surface area to volume ratios, ensuring consistent contact with vessel walls for complete occlusion. The spherical geometry also prevents aggregation and ensures predictable flow characteristics and degradation patterns, while maintaining ease of delivery through smooth, rounded profiles that navigate vascular structures effectively.
3Adaptability or versatility
If resorbable microspheres are used to allow temporary blockage, then blood vessel healing is enabled, but the duration of occlusion control becomes critical
Solution Approach 1:
The patent controls the duration of action by adjusting material parameters including gelatin concentration (10-30% w/v), cross-linking degree (0.1-5% cross-linker), and microsphere size (50-1500 micrometers). These parameter adjustments allow precise control over degradation rate, enabling the occlusion to last from hours to weeks depending on the specific application requirements, while maintaining the ability to heal subsequently.
Solution Approach 2:
The embolic material uses composite construction combining gelatin base matrix with cross-linking agents (glutaraldehyde, formaldehyde) and potential surface coatings. This composite structure provides initial structural integrity for durable occlusion while the cross-linked network degrades at controlled rates through enzymatic breakdown, enabling temporary embolization with predictable timing for vessel healing.
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 resorbable microspheres provide effective and predictable temporary occlusion, reducing the risk of complications and allowing for the reestablishment of blood flow, while their spherical shape ensures complete contact with vessel surfaces, preventing clogging and ensuring safe delivery.
Implementation Method 1
The resorbable microspheres can resorb during an in vivo time period of between about 24 hours and about 15 weeks, inclusive
Data Source
AI summary
Embolic materials, suspensions, kits and related methods useful for embolization are disclosed. An embolic material can comprise a resorbable microsphere including cross-linked gelatin as its primary ingredient and having a substantially spherical shape with a diameter of about 50 micrometers to about 1,500 micrometers, inclusive. The microsphere can optionally include one or both of a marker or an active agent. The microsphere can be cross-linked, such as with glutaraldehyde or formaldehyde, which can affect the microsphere's in vivo degradation profile and ability to withstand a sterilization process at certain temperatures. In an embodiment, the microspheres can resorb during an in vivo time period of between about 24 hours and about 15 weeks, inclusive. An embolization suspension can include a plurality of resorbable microspheres and a liquid carrier, and the suspension can be disposed in a syringe, vial or other applicator for administration to a patient.