Hybrid Core-Shell Microcapsules for Stable Encapsulation and Release

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Solution Overview

Problem

Existing microcapsules, particularly those based on alginate, suffer from mechanical instability and high porosity, leading to unsuitable encapsulation of active ingredients, and lack an appropriate balance between mechanical stability, controlled release, and biodegradability.

Innovation Solution

Hybrid organic-inorganic core-shell microcapsules are developed with a shell network comprising anionic and cationic polymers, an alkali metal silicate, and a coupling agent, such as organosilane with quaternary ammonium or carboxylate groups, forming covalent and ionic bonds, resulting in compact capsules with reduced leakage and controlled release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional microcapsules are used, then ease of manufacture is maintained, but manufacturing precision and stability of composition deteriorate due to polydispersity

Engineering Contradiction:
Improvecapsule size uniformityVSAvoidcore-shell structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention segments the microcapsule structure into distinct core and shell components formed through sequential coating steps. The core contains the active ingredient while the shell provides protective and functional properties. This segmentation allows independent optimization of each component and achieves uniform size distribution through controlled deposition processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The microcapsules employ a nested structure where the active ingredient is encapsulated within the core, which is then surrounded by one or more shell layers. This nested architecture enables precise control over capsule dimensions and composition while maintaining manufacturing feasibility through layer-by-layer assembly.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Stability of the object's composition

If polydisperse microcapsules are used, then ease of manufacture is maintained, but stability of composition deteriorates due to variable active ingredient content

Engineering Contradiction:
Improveactive ingredient content uniformityVSAvoidactive ingredient loading control
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The invention controls the composition uniformity by precisely adjusting process parameters during coating, including monomer concentration, crosslinker ratio, pH, temperature, and reaction time. These parameter changes enable consistent active ingredient loading across all capsules while maintaining compositional stability through controlled polymerization and crosslinking processes.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If additional functional properties are added to microcapsules, then adaptability improves, but device complexity increases

Engineering Contradiction:
Improvefunctional property integrationVSAvoidcapsule structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The microcapsule shell is designed with multi-functionality, incorporating properties such as pH responsiveness, temperature sensitivity, magnetic targeting capability, or enzymatic degradation. A single shell structure simultaneously provides mechanical protection, controlled release functionality, and targeted delivery capabilities, reducing the need for multiple separate components and minimizing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The shell is constructed from composite materials that combine multiple functional properties within a single structure. For example, the shell may incorporate pH-sensitive polymers, magnetic nanoparticles, or temperature-responsive components alongside the base polymer matrix. This composite approach enables multiple functions to be integrated without proportionally increasing structural complexity.

Inventive Principle:
Principle #40Composite materials

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 microcapsules exhibit high encapsulation efficiency, mechanical stability, and controlled release of active ingredients, ensuring safety and effective delivery while being biodegradable.

Implementation Method 1

crosslinking agent comprising a compound of formula (II) or a salt thereof, in which R1 to R6 independently represent a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 alkoxy group, a C6-C10 aryl group or a C6-C10 arylalkyl group, provided that at least two of R1 to R6 represent a crosslinking group

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

Hybrid core-shell microcapsules for encapsulating active ingredients... wherein the core comprises magnetic particles... magnetic resonance imaging

Methodology Applied
Scientific EffectMagnetic relaxation: Magnetic Field

Data Source

PatentEP4192613B1Hybrid core-shell microcapsules for encapsulating active ingredients
Publication Date: 2026.05.06 FUNDACIO EURECAT
  • EP4192613B1 patent drawingFigure 1
  • EP4192613B1 patent drawingFigure 2~3
  • EP4192613B1 patent drawingFigure 4~5

AI summary

It relates to a organic-inorganic core-shell microcapsule, wherein a) the shell forms a network which comprises: i) an anionic polymer which comprises a plurality of carboxylate or sulfonate groups, ii) a cationic polymer which comprises a plurality of quaternary ammoniumgroups, iii) an alkali metal silicate or a silicate precursor, and iv) a coupling agent which is an organosilane comprising at least a terminal group selected from a quaternary ammonium group, hydroxy, and carboxylate, and b) the core comprises one or more active ingredients in liquid form. It also relates to a process for its preparation, to a composition comprising the microcapsules and one or more excipients or carriers, and to their use as a disinfectant or for the delivery of active ingredients.