Lanthanide Chelate Lipid Nanoparticles for High-Sensitivity TRF Immunoassays
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Solution Overview
Problem
Current immunoassay technologies, such as those using DELFIA®, face limitations in sensitivity due to the limited number of lanthanide chelates that can be coupled to antibodies or streptavidin, restricting the detection sensitivity of time-resolved fluorescence (TRF) assays.
Innovation Solution
The development of lanthanide chelate lipid nanoparticles, which carry thousands of lanthanide atoms, serves as labels in TRF bioaffinity assays, enhancing sensitivity by increasing the number of lanthanide chelates per particle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lanthanide chelates are coupled to antibodies or streptavidin in DELFIA® assays, then time-resolved fluorescence detection is achieved, but the number of lanthanide chelates per molecule is limited (6-8 Eu per streptavidin), restricting detection sensitivity
Solution Approach 1:
The patent creates composite lipid nanoparticles consisting of a lipid core structure with multiple lanthanide chelates attached to lipid molecules. This composite structure allows thousands of lanthanide atoms to be assembled into a single particle, dramatically increasing the quantity of fluorescent label beyond what is possible with antibody or streptavidin conjugation.
Solution Approach 2:
Instead of attaching lanthanide chelates directly to biological molecules (antibodies/streptavidin), the patent uses lipid nanoparticles as synthetic copies or alternatives that can carry much higher loads of lanthanide chelates. The lipid nanoparticle serves as a synthetic platform that replicates the binding function while enabling higher signal amplification.
2Measurement precision
If polystyrene beads with thousands of Eu per particle are used to improve TRF sensitivity, then detection sensitivity increases in some cases, but nonspecific interactions with polyclonal antisera occur
Solution Approach 1:
The patent changes the material parameter of the nanoparticle from polystyrene to lipid composition. This parameter change fundamentally alters the surface properties and interaction characteristics of the particle, eliminating nonspecific interactions with polyclonal antisera while retaining the ability to carry thousands of lanthanide chelates for high-sensitivity detection.
Solution Approach 2:
The lipid nanoparticle structure allows for specific functionalization at the surface (with biotin or other ligands) while the core lipid structure provides inert, non-interacting properties. This creates local quality differentiation where only specific binding sites are active, reducing nonspecific interactions throughout the particle surface.
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
This approach significantly improves the sensitivity of TRF assays, achieving detection levels that are 5- to 20-fold more sensitive than existing commercial assays, while maintaining low non-specific binding.
Implementation Method 1
time-resolved fluorescence (TRF), a non-radioisotope, non-enzymatic fluorescence label procedure that utilizes the unique long-lifetime fluorescence (measured in milliseconds after excitation) of certain lanthanide chelates
Implementation Method 2
a lipid nanoparticle comprising: a) a lipid with an aliphatic chain, wherein the chain length ranges from C19 to C50, attached to a linker moiety; b) a lipid with an aliphatic chain, wherein the chain length ranges from C19 to C50, attached to a lanthanide chelate
Data Source
AI summary
Lanthanide chelate lipid nanoparticles, and methods of their synthesis and use are described. Biological molecules labeled with the lipid nanoparticles, useful in bioaffinity assays with improved sensitivities are also described.