Core-Double Shell Biodegradable Nanoprobe for Prolonged Biodegradation

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Solution Overview

Problem

Existing upconversion nanoparticles (UCNPs) are chemically stable and physiologically inert, leading to short biodegradation times and low upconversion luminescent efficiency, limiting their application in biomedical fields.

Innovation Solution

A biodegradable upconversion nanoparticle with a core-double shell structure, comprising a core layer, an inorganic host matrix outer shell layer, and a transition layer acting as an energy transfer network, where the core layer is larger than the outer shell and transition layers, and includes lanthanide-doped nanoparticles, enhancing energy transfer and absorption of near-infrared radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If UCNPs are designed with biodegradable nanocomponents for kidney clearance, then biodegradation time is extended, but upconversion luminescent efficiency decreases

Engineering Contradiction:

Improvebiodegradation timeVSAvoidupconversion luminescent efficiency

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The UCNP is divided into a biodegradable core (Na3ZrF7:Yb,Er/Ca) and a protective double shell (NaYF4:Yb,Ca@NaNdF4:Yb,Ca). The core provides biodegradability and intrinsic UCL, while the shell protects the core and enhances UCL through sensitizer doping, resolving the contradiction between biodegradation and luminescent efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a composite structure combining biodegradable Na3ZrF7 core material with protective NaYF4 and NaNdF4 shell materials. This composite approach allows the core to degrade over time (extending biodegradation time) while the shell maintains high UCL efficiency through its optically active dopants

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If UCNPs use chemically stable crystal lattices, then chemical stability is improved, but biodegradation time becomes too short

Engineering Contradiction:

Improvechemical stabilityVSAvoidbiodegradation time

Core Design Contradiction:

Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

Different regions of the UCNP have different properties: the core uses biodegradable Na3ZrF7 with lower chemical stability to enable extended degradation, while the shell uses chemically stable NaYF4 and NaNdF4 to protect the core. This local differentiation resolves the contradiction between chemical stability and biodegradation time

Inventive Principle:

Principle #3Local quality

3Reliability

If the core layer size is increased to enhance UCL intensity, then upconversion luminescent efficiency is improved, but nanoparticle clearance by kidney is hindered

Engineering Contradiction:

Improveupconversion luminescent efficiencyVSAvoidnanoparticle size

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The large UCL-generating core is nested within a protective double shell, allowing the core to be larger than 5.5 nm for high UCL efficiency while the overall nanoparticle size (core + shell) remains under 5.5 nm for kidney clearance. The shell acts as a space-efficient protective layer

Inventive Principle:

Principle #7Nested doll (Nesting)

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 core-double shell structure ensures a prolonged biodegradation time and significantly improved upconversion luminescent efficiency, allowing the nanoparticles to remain in the body longer for effective biomedical applications.

Implementation Method 1

a transition layer positioned between the core layer and the outer shell layer and functioning as an energy transfer network

Methodology Applied

Scientific EffectEnergy transfer:

Implementation Method 2

The core of the upconversion nanoparticles (UCNPs) consists of a degradable Na3ZrF7 matrix doped with Yb, Er/Tm, and Ca. This core emits upconversion luminescence (UCL) due to the activator ions Er/Tm

Methodology Applied

Scientific EffectUpconversion luminescence: Photoluminescence

Implementation Method 3

The outer shell layer features a high concentration of Nd/Yb sensitizers within a NaY/NdF4 matrix, also incorporating Ca. This composition is designed to absorb a high amount of near-infrared (NIR) radiation, thereby enhancing the UCL intensity

Methodology Applied

Scientific EffectNear-infrared radiation absorption: Absorption (EM radiation)

Implementation Method 4

The presence of a moderate concentration of Yb in this layer facilitates efficient energy migration between the outer shell and the degradable core, helping to prevent undesired quenching effects from Nd/Yb in the outer shell

Methodology Applied

Scientific EffectEnergy migration:

Data Source

PatentUS20250213696A1Highly luminescent biodegradable upconversion nanoprobe having long decomposition time

Publication Date: 2025.07.03 RES & BUSINESS FOUND SUNGKYUNKWAN UNIV

AI summary

An example provides a biodegradable upconversion nanoparticle with a core-double shell structure including: a core layer; an inorganic host matrix outer shell layer; and a transition layer positioned between the core layer and the outer shell layer and functioning as an energy transfer network, wherein the core layer, the outer shell layer, and the transition layer are biodegradable. By means of such a structure, a long decomposition time and high luminescent efficiency are ensured, and thus the biodegradable upconversion nanoparticle may remain in an organism body for a long time to allow the effect to persist.