Cationic Phosphate-Crosslinked Starch Nanoparticles for Tooth Remineralization
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Solution Overview
Problem
Existing dental remineralization agents, such as those with a negative charge, are repelled by carious lesions due to electrostatic forces, limiting their effectiveness in targeting and delivering calcium and fluoride for tooth remineralization, and there is a need for improved methods to address early-stage caries and dentinal hypersensitivity.
Innovation Solution
Starch nanoparticles are cross-linked with phosphate compounds and optionally cationized with calcium and fluoride, achieving a positive zeta potential at acidic pH to target and deliver minerals to demineralized tooth areas, using an emulsion process to enhance retention and delivery of active agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing dental remineralization agents with negative charge are used, then calcium and fluoride can be delivered to teeth, but the agents are repelled by carious lesions due to electrostatic forces, limiting their effectiveness
Solution Approach 1:
The patent inverts the conventional negative charge of remineralization agents to a positive charge. The starch nanoparticles are cationized to acquire a positive zeta potential, which enables electrostatic attraction to the negatively charged carious lesions rather than repulsion, thereby improving delivery effectiveness to the target site
Solution Approach 2:
The patent changes the electrical charge parameter of the remineralization agent from negative to positive. By cationizing the starch nanoparticles, the zeta potential is shifted to positive values at physiological pH, fundamentally altering the electrostatic interaction with carious lesions and enabling effective targeting
2Stability of the object's composition
If phosphate crosslinking is used to form starch nanoparticles, then the nanoparticle structure is stabilized, but the nanoparticles acquire a negative charge that causes repulsion from carious lesions
Solution Approach 1:
The patent combines two functions into a single integrated process: phosphate crosslinking for structural stabilization and cationization for charge reversal. The starch nanoparticles simultaneously achieve structural integrity through phosphate crosslinks and positive surface charge through cationic modification, resolving the contradiction between stability and electrostatic attraction
Solution Approach 2:
The patent creates a composite nanoparticle structure combining starch polymer matrix with phosphate crosslinks and cationic functional groups. This composite structure integrates multiple properties: structural stability from crosslinking, positive charge from cationization, and biocompatibility from starch, thereby overcoming the limitation of negative charge while maintaining stability
3Reliability
If cationization is applied to starch nanoparticles to achieve positive charge for targeting caries, then electrostatic attraction to lesions is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent performs cationization as a preliminary step during nanoparticle formation rather than as a subsequent modification step. By incorporating the cationization reaction into the nanoparticle synthesis process, the positive charge is established during particle formation, simplifying the overall manufacturing workflow while achieving the desired targeting efficiency
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 nanoparticles effectively target and deliver calcium and fluoride to demineralized tooth areas, promoting remineralization and reducing sensitivity, with potential for pH-triggered targeting and sustained release of minerals.
Implementation Method 1
a phosphate crosslinking agent is present in the water phase... The crosslinking agent thereby provides a useful element
Implementation Method 2
The emulsion or emulsions are produced using an ultra-high shear mixer... a phase inversion emulsion (PIE) process
Implementation Method 3
Dental caries and other remineralized areas of a tooth are negatively charged... The nanoparticles have a positive zeta potential at the pH of saliva
Implementation Method 4
The addition of a calcium salt in particular serves to make the charge of the nanoparticle more suitable for targeting to caries while also providing another element, calcium, that is useful for remineralizing teeth
Data Source
AI summary
A phosphorous compound such as STMP is used as a cross-linking agent while making a starch nanoparticle in an emulsion process. Negative charge of the nanoparticle is reduced or reversed by adding cations and/or cationizing the starch optionally while forming the nanoparticles. Anionic active agents, such as fluoride or fluorescein, are optionally incorporated into the nanoparticle during the formation process. For example, a fluoride salt can also be used, which promotes the crosslinking reaction while also providing fluoride in the nanoparticle. The retention of both calcium and fluoride in the nanoparticle is improved when both salts are used. Alternatively, the nanoparticle may be used without added calcium and/or fluoride. The nanoparticles may be useful for tooth remineralization, the treatment of dentinal hypersensitivity, to treat caries, or as a diagnostic agent to locate carious lesions.