Sub-visible Particle Quantification via Dissolvable Sealant Filtration
Solution Overview
Problem
Current methods for quantifying sub-visible particles, such as nanoparticles, in liquid samples are imprecise due to indirect detection techniques that rely on bound probes and affinity, failing to provide a clear count of both infectious and non-infectious particles, which is crucial for assessing gene therapy product quality.
Innovation Solution
A high-precision method using scanning electron microscopy (SEM) with a filter membrane and dissolvable sealant, allowing direct visualization and enumeration of particles on the membrane, enabling precise counting without the need for probes and improving particle distribution for accurate analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If indirect detection techniques using bound probes are used, then particle quantification can be performed, but measurement precision deteriorates due to variable probe binding and affinity
Solution Approach 1:
The invention extracts the detection process from indirect probe-based methods to direct electron microscopy imaging. By removing the intermediary probe binding step and directly imaging particles with SEM, the method eliminates variability introduced by probe affinity and binding stoichiometry, achieving precise particle enumeration without complex probe design or optimization
Solution Approach 2:
The invention replaces the biochemical detection system (probes binding to particles) with a physical imaging system (electron microscopy). This substitution transitions from chemical affinity-based detection to direct visual observation, eliminating the limitations of probe variability while maintaining detection capability through high-resolution imaging
2Measurement precision
If light scattering-based techniques are used, then particle detection can be performed, but measurement precision deteriorates due to inability to resolve individual particles in clusters
Solution Approach 1:
The invention replaces light scattering detection with electron microscopy imaging. The electron beam provides significantly higher spatial resolution compared to light wavelengths, enabling individual particles within clusters to be visually distinguished and counted. This physical imaging approach overcomes the diffraction limit that constrains light-based methods
3Measurement precision
If sampling is performed to analyze particles, then analysis can be conducted, but measurement precision deteriorates due to uneven particle distribution and sampling errors
Solution Approach 1:
The invention transitions from bulk liquid sampling to two-dimensional planar deposition of particles on a substrate. By spreading particles across a surface area rather than analyzing a small volume, the method effectively increases the sampled quantity while maintaining visual resolution, eliminating the need for complex sampling statistics and reducing sampling errors
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 method allows for direct, high-resolution detection and enumeration of sub-visible particles, providing accurate particle counts and distribution analysis, enhancing the assessment of gene therapy product quality and reducing sampling errors.
Implementation Method 1
The liquid dissolves the sealant in the pores located directly below the sample droplet
Implementation Method 2
The liquid flows through the pores in which the sealant has been dissolved and the sub-visible particles remain on top of the filter membrane
Implementation Method 3
The filter membrane is in operational engagement with a vacuum chamber
Implementation Method 4
scanning electron microscopy (SEM) or other electron microscopy techniques
Data Source
AI summary
The method is for quantification of sub-visible particles. A filter membrane is provided that has a plurality of pores defined therethrough. The pores are sealed with a sealant such as glycine or poly-vinyl alcohol (PVA). A sample droplet, containing liquid and sub-visible particles, is applied onto the filter membrane. The liquid dissolves the sealant in pores disposed directly below the sample droplet. The liquid flows through the pores in which the sealant has been dissolved and the sub-visible particles remain on top of the filter membrane. The particles are enumerated in an electron microscope.