Core-Shell Chromatography Beads for Enveloped Virus Purification
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Solution Overview
Problem
Current methods for purifying enveloped viruses, such as lentivirus, suffer from low recovery rates (typically 10-20%) and instability due to sensitivity to shear forces, salt, and narrow pH and conductivity requirements, making downstream purification processes challenging.
Innovation Solution
A chromatography process using porous beads with an inner core and outer shell, performing chromatographic separation at a pH of 6.0 to less than 7.4, allows for high infectious recovery (70-100%) of enveloped viruses by capturing them in the flow-through fraction while removing impurities like host cell proteins and DNA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chromatographic purification methods are used for enveloped viruses, then purification is achieved, but recovery rate is low (10-20%) due to virus instability and sensitivity to shear forces, salt, and pH variations
Solution Approach 1:
The invention changes the pH parameter to a range of 6.0 to less than 7.4, which is outside the conventional narrow pH range (7.0-7.4) used for lentivirus purification. This parameter change stabilizes the virus particles and enables high recovery rates (70-100%) while maintaining purification quality. The patent explicitly states that lentiviruses are stable in a very narrow pH range (7.0-7.4) but the invention successfully operates at lower pH values to improve recovery.
Solution Approach 2:
The chromatography medium is segmented into an inner porous core and an outer porous shell with different pore sizes. The outer shell has pore sizes that exclude virus particles (20 nm and larger) while allowing smaller impurities to pass through. This segmentation enables the virus to be retained in the flow-through while impurities are captured by the hydrophobic core, achieving both high recovery and purification.
2Manufacturing precision
If multistep purification processes are used to reduce impurities to approved levels, then purification quality is improved, but process time increases and virus stability decreases
Solution Approach 1:
The invention merges the purification and recovery functions into a single chromatographic step. The unique combination of pH control (6.0 to less than 7.4) and the core-shell chromatography medium structure allows simultaneous achievement of high virus recovery (70-100%) and effective impurity removal, eliminating the need for multiple sequential purification steps and reducing overall process time.
Solution Approach 2:
The outer porous shell acts as an intermediary structure that selectively interacts with virus particles based on size exclusion. It allows smaller impurities to pass through to the hydrophobic core while retaining larger virus particles in the flow-through. This intermediary mechanism enables effective separation in a single step without requiring multiple purification operations.
3Manufacturing precision
If conventional chromatography media with hydrophobic cores are used, then impurity removal is effective, but enveloped viruses are lost due to adsorption to the hydrophobic surface
Solution Approach 1:
The chromatography medium is divided into two functional zones: an outer porous shell with size-exclusion properties and an inner porous core with hydrophobic binding capability. The outer shell's pore sizes are specifically designed to exclude virus particles (20 nm and larger) while allowing smaller impurities to reach the hydrophobic core. This segmentation prevents virus adsorption to the hydrophobic core while maintaining effective impurity removal, achieving both high recovery and purification.
Solution Approach 2:
The outer porous shell serves as a protective intermediary between the virus particles and the hydrophobic core. It selectively permits smaller impurities to pass through to the core for binding while physically blocking larger virus particles from contacting the hydrophobic surface. This intermediary structure prevents unwanted virus adsorption while maintaining the impurity removal function of the hydrophobic core.
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 process achieves a significant increase in infectious virus recovery (at least 30-100%) while maintaining particle integrity, offering a short process time and low shear forces, suitable for sensitive biological particles.
Implementation Method 1
the pore size of the shell does not allow particles having a size of 20 nm and larger to permeate into the bead and interact with the core
Implementation Method 2
the core is capable of binding molecules via hydrophobic interactions
Implementation Method 3
A chromatography process using porous beads with an inner core and outer shell, performing chromatographic separation at a pH of 6.0 to less than 7.4
Data Source
AI summary
A chromatography medium comprising porous beads having an inner porous core and an outer porous shell is used for chromatographic separation of enveloped or membranous biological particles from impurities such as contaminant DNA and/or protein. The core is capable of binding molecules via hydrophobic interactions; however, the pore size of the shell does not allow particles having a size of 20 nm and larger to permeate into the bead and interact with the core. The separation is performed at a pH of less than 7.4. The enveloped or membranous biological particles may have been subjected to a prior chromatographic capture step. When used for purification of enveloped virus particles the inventive process was found to yield a remarkably high rate of infectious virus particles.