Hydrogel Capsule Crosslinking via Aerosol Pre-Treatment
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Solution Overview
Problem
Existing encapsulation processes for hydrogel capsules often result in breakage during crosslinking, leading to partial mixing of the core composition with the hydrogel, excessive use of surfactants and crosslinking agents, and altered properties of the encapsulated content, which can be costly and reduce the effectiveness of active agents or cause cell death.
Innovation Solution
A process where mixed drops coextruded from a hydrogel solution and a composition of interest pass through a crosslinking aerosol, allowing for at least partial crosslinking of the hydrogel layer before impact, reducing the need for surfactants and minimizing contact with crosslinking agents, and enabling the formation of capsules with controlled shape and structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional crosslinking bath method is used, then crosslinking of hydrogel layer is achieved, but capsule breakage occurs during impact
Solution Approach 1:
The patent applies preliminary action by crosslinking the hydrogel layer before the capsule impacts the bath. The crosslinking process is initiated during the fall through the aerosol, creating a pre-crosslinked shell that maintains structural integrity during impact, thereby preventing capsule breakage while achieving the desired crosslinked structure.
2Reliability
If surfactant is added to prevent breakage, then capsule integrity is maintained, but content properties are altered
Solution Approach 1:
The patent extracts and eliminates the need for surfactants by implementing pre-impact crosslinking. The crosslinked hydrogel shell provides sufficient mechanical strength to prevent capsule breakage during impact without requiring any surfactant additives, thereby avoiding alteration of the encapsulated content properties while maintaining capsule integrity.
3Productivity
If high concentration crosslinking agent is used, then crosslinking speed is increased, but content penetration and property alteration occur
Solution Approach 1:
The patent applies preliminary action by initiating crosslinking before impact occurs. The crosslinking process begins during the fall through the aerosol, allowing the hydrogel shell to form a protective barrier that prevents excessive crosslinking agent penetration into the capsule content, thereby maintaining both crosslinking speed and content integrity.
Solution Approach 2:
The patent transitions from a traditional bath-based crosslinking approach to an aerosol-based approach. This dimensional change from liquid bath to aerosol environment allows for controlled crosslinking agent delivery that achieves rapid crosslinking of the hydrogel shell while minimizing penetration into and alteration of the encapsulated content.
4Manufacturing precision
If rinsing steps are performed to remove crosslinking agent and surfactant, then content purity is improved, but production yield is reduced and cost increases
Solution Approach 1:
The patent extracts and eliminates the need for extensive rinsing steps by using pre-impact crosslinking with aerosol. This approach minimizes crosslinking agent and surfactant residue on the capsule surface and within the content, thereby achieving high content purity without the need for time-consuming and yield-reducing rinsing operations.
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 process prevents capsule breakage, reduces the risk of content alteration, and allows for the production of capsules with a high yield and controlled structure without the need for extensive rinsing, maintaining the integrity and effectiveness of the encapsulated content.
Implementation Method 1
at least partial crosslinking of the hydrogel layer around the drop of composition of interest before the capsules impact the recovery bath
Implementation Method 2
pass through an aerosol formed of microparticles (liquid or solid) comprising a crosslinking agent. The microparticles coalesce on the surface of the mixed drops during their fall through said aerosol
Data Source
AI summary
The invention relates to a process for producing a plurality of capsules, each comprising an external shell of crosslinked hydrogel surrounding a central core, according to which a hydrogel solution and a composition of interest, intended to form the central core, are concentrically co-extruded so as to form mixed drops, each comprising a layer of hydrogel solution surrounding a drop of liquid composition of interest, characterized in that the co-extrusion step is carried out above a crosslinking aerosol so that the mixed drops pass through said crosslinking aerosol, such that the layer of hydrogel solution at least partially crosslinks around the drop of liquid composition of interest on contact with said aerosol.