Functionalized Mesoporous Silica Particles for Stable Extended NO Release

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Solution Overview

Problem

Existing NO-releasing systems face challenges in achieving targeted, tunable, and extended delivery of nitric oxide, particularly in hydrophilic materials, due to stability issues with S-nitrosothiol (RSNO) donors under ambient light and heat, which limits their application in medical devices.

Innovation Solution

Mesoporous silica nanoparticles (MSNs) are functionalized with S-nitrosothiol (RSNO) donors both on the exterior surface and within pores, utilizing the cage effect to enhance stability and allow for larger NO payloads and extended release durations up to 20 days without particle leaching or cold storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If S-nitrosothiol (RSNO) donors are used in hydrophilic materials, then NO release can be achieved, but stability under ambient light and heat deteriorates

Engineering Contradiction:

Improvestability of RSNO donorsVSAvoiddegradation under ambient light and heat

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent utilizes mesoporous silica nanoparticles with controlled pore sizes and high surface area to encapsulate RSNO donors. The porous structure provides a protective microenvironment that shields the light-sensitive and heat-sensitive RSNO groups from ambient degradation while maintaining accessibility for NO release. The mesoporous structure acts as a physical barrier that reduces direct exposure to harmful environmental factors.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent creates a composite system combining silica nanoparticles with RSNO functional groups. This composite material leverages the stability of the silica framework to protect the unstable RSNO moieties. The composite structure integrates the protective properties of inorganic silica with the NO-donating capability of organic RSNO groups, achieving enhanced overall stability.

Inventive Principle:

Principle #40Composite materials

2Duration of action of moving object

If RSNO donors are functionalized on particle surfaces, then NO release duration can be extended, but particle leaching may occur

Engineering Contradiction:

ImproveNO release durationVSAvoidparticle leaching

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The patent applies different functionalization strategies to different locations on the particle surface. RSNO donors are selectively placed on the exterior surface for controlled release, while the interior pore structure maintains structural integrity. This localized functionalization allows extended NO release without compromising particle stability or causing leaching.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent performs preliminary functionalization of RSNO groups onto the silica nanoparticle surfaces during synthesis. This preliminary action ensures that the RSNO groups are firmly attached to the stable silica framework before the particles are deployed, preventing subsequent leaching while enabling prolonged NO release over extended periods.

Inventive Principle:

Principle #10Preliminary action

3Quantity of substance

If mesoporous silica nanoparticles are used to increase NO payload, then release capacity increases, but particle leaching risk increases

Engineering Contradiction:

ImproveNO payloadVSAvoidparticle leaching

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent exploits the mesoporous structure to accommodate large quantities of RSNO donors within the pore network. The high surface area and controlled porosity allow maximum loading of NO donors while the rigid silica framework maintains structural integrity and prevents particle leaching. The porous structure provides a protective matrix that holds the NO donors in place.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent segments the NO donor functional groups throughout the porous structure rather than concentrating them in a single location. This segmentation distributes the RSNO groups across the entire particle surface and within pores, maximizing NO payload while the distributed attachment points prevent particle leaching by anchoring the functional groups to the stable silica matrix.

Inventive Principle:

Principle #1Segmentation

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 MSN-based NO-releasing particles provide stable, tunable, and extended NO delivery, suitable for a wide range of medical devices, including wound dressings and implanted sensors, with release durations independent of water uptake and pH, improving device performance and reducing thrombosis and inflammation.

Implementation Method 1

utilizing the cage effect to enhance stability

Methodology Applied

Scientific EffectCage effect:

Implementation Method 2

nitric oxide donors... exhibit a total nitric oxide release duration

Methodology Applied

Scientific EffectDecomposition: Decomposition (biological)

Data Source

PatentUS20250249122A1Extended nitric oxide-releasing polymers via functionalized mesoporous silica nanoparticles

Publication Date: 2025.08.07 THE UNIV OF NORTH CAROLINA AT CHAPEL HILL

AI summary

The subject matter disclosed herein is directed to nitric oxide releasing particles comprising a mesoporous silica network. Also disclosed are compositions comprising one or more nitric-oxide releasing particles and a polymer. In one aspect, the particles are admixed with the polymer. The compositions exhibit high payloads of nitric oxide release without particle leaching or the need for extremely cold storage conditions.