Capillary Action Test Using Rare-Earth Nanoparticles for Sensitive Detection
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Solution Overview
Problem
Capillary diffusion tests, particularly those using gold nanoparticles, suffer from low detection sensitivity and require complex synthesis methods for alternative probes, leading to instability and high costs, making them unsuitable for rapid, inexpensive, and sensitive detection.
Innovation Solution
Utilize photoluminescent inorganic nanoparticles doped with rare earth ions, such as YVO4:Eu or GdVO4:Eu, which emit after single-photon absorption, allowing for improved sensitivity and stability under UV excitation, with a large Stokes shift for effective signal detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gold nanoparticles are used as probes in capillary diffusion tests, then the test can be performed rapidly and at low cost, but the detection sensitivity is low
Solution Approach 1:
The patent changes the optical parameters of the probe by replacing gold nanoparticles with photoluminescent inorganic nanoparticles that have different optical properties. These new probes absorb light at specific wavelengths and emit at longer wavelengths, enabling detection at concentrations 10-100 times lower than gold nanoparticle-based tests, thus resolving the contradiction between sensitivity and speed by maintaining rapid capillary diffusion while achieving high sensitivity through optimized optical detection parameters
Solution Approach 2:
The patent uses composite inorganic nanoparticles containing rare earth ions (such as Eu, Dy, Sm) doped into matrices like YVO4 or GdVO4. These composite materials combine the advantages of inorganic stability with photoluminescent properties, achieving both rapid detection capability and high sensitivity that gold nanoparticles alone cannot provide
2Measurement precision
If alternative probes are used to improve detection sensitivity, then sensitivity increases, but synthesis methods become more complex and costs increase
Solution Approach 1:
The patent employs inorganic nanoparticles that can be synthesized through relatively simple, scalable methods compared to complex organic fluorophore conjugation processes. The inorganic nature of these particles allows for robust, reproducible synthesis that maintains stability during storage and handling, reducing manufacturing complexity while achieving the desired sensitivity improvement
3Measurement precision
If photoluminescent probes are used to improve sensitivity, then detection sensitivity improves, but the probes may exhibit photobleaching or emission flicker
Solution Approach 1:
The patent replaces organic fluorophore probes with inorganic photoluminescent nanoparticles that have fundamentally different photophysical properties. These inorganic probes absorb photons and emit after a characteristic lifetime, avoiding the photobleaching and flicker issues of organic dyes. The inorganic material structure provides exceptional stability against photodegradation, maintaining reliable signal output throughout the test duration and across multiple readings
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
Achieves detection sensitivity improved by at least an order of magnitude, enabling rapid, qualitative, semi-quantitative, and quantitative analysis with a simple reading system, comparable to ELISA tests, suitable for point-of-care diagnostics.
Implementation Method 1
photoluminescent inorganic nanoparticles with controlled optical and physicochemical properties
Implementation Method 2
with a large Stokes shift for effective signal detection
Implementation Method 3
emitting after single-photon absorption
Implementation Method 4
emitting after single-photon absorption
Data Source
Figure 1~2
Figure 3-a
Figure 3-b
AI summary
The invention relates to an in vitro method for the detection and/or quantification of a biological or chemical substance of interest in a liquid sample, by means of a capillary action test, using, as probes, photoluminescent inorganic nanoparticles, of formula A1-xLnxVO4(1-y)(PO4)y (II), in which Ln is selected from europium (Eu), dysprosium (Dy), samarium (Sm), neodymium (Nd), erbium (Er), ytterbium (Yb), thulium (Tm), praseodymium (Pr), holmium (Ho) and the mixtures thereof; A is selected from yttrium (Y), gadolinium (Gd), lanthane (La), lutetium (Lu), and the mixtures thereof; 0 < x < 1; and 0 ≤ y < 1, said method implementing the detection of luminescence of an emission lifetime shorter than 100 ms of the nanoparticles, after one-photon absorption, by excitation of the matrix at a wavelength which is less than or equal to 320 nm. The invention also relates to a capillary action test comprising the abovementioned nanoparticles as probes, and to the use of such a method for in vitro diagnostic purposes.