Three-Layer Filter Unit for Viral Vector Purification Without Clogging

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Solution Overview

Problem

Existing methods for purifying solutions containing viral vectors face issues of premature clogging and pressure increase due to inadequate pore size combinations in filters, requiring large filters for large volumes, which hinder efficient purification.

Innovation Solution

A filter unit comprising three layers with specific pore diameter and thickness ratios (30 μm ≥ Da > Db > Dc ≥ 0.01 μm, 6 ≥ Da / Db ≥ 2.8) and fibrous filters with 70-95% porosity, using materials like polyolefin and polysulfone-based polymers, arranged to efficiently remove impurities in a sequential manner.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If filters with different pore sizes are used sequentially for purification, then purification efficiency is improved, but premature clogging and pressure increase occur

Engineering Contradiction:
Improvepurification efficiencyVSAvoidclogging and pressure increase
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The filter is divided into three distinct separation functional layers (a, b, c) with progressively smaller pore diameters arranged in sequence from the inlet. Each layer captures different size ranges of impurities, distributing the clogging load across multiple layers rather than concentrating it in a single filter layer, thereby maintaining reliable purification while reducing premature clogging.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each separation functional layer is designed with specific local properties: layer a has the largest pores for initial impurity removal, layer b has intermediate pores for medium-sized impurities, and layer c has the smallest pores for fine purification. This localized differentiation of pore sizes optimizes each layer's function while preventing any single layer from becoming overwhelmed and clogged.

Inventive Principle:
Principle #3Local quality

2Productivity

If a large filter is used to process large volume, then processing capacity is improved, but device size and complexity increase

Engineering Contradiction:
Improveprocessing capacityVSAvoidfilter size
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The filter structure transitions from a single-layer planar configuration to a multi-layer stacked configuration with depth dimension. By arranging three separation functional layers with different pore sizes in sequence along the flow direction, the filter achieves enhanced purification capacity without increasing the lateral footprint, effectively processing large volumes while maintaining compact device dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution effectively suppresses clogging and pressure increase, enabling efficient purification of biopharmaceuticals, food ingredients, and beverage ingredients by sequentially removing impurities through the filter unit.

Implementation Method 1

a separation functional layer 'a' section with an average pore diameter Da, a separation functional layer 'b' section with an average pore diameter Db, and a separation functional layer 'c' section with an average pore diameter Dc

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentEP4681804A1Filter unit, purification device, and method for producing purified liquid
Publication Date: 2026.01.21 TORAY INDUSTRIES INC
  • EP4681804A1 patent drawingFigure 1
  • EP4681804A1 patent drawingFigure 2
  • EP4681804A1 patent drawingFigure 3

AI summary

The present invention provides a filter unit, a purification apparatus, a purified liquid, and a method of producing purified liquid, wherein a filter is arranged that is suitable for the efficient purification of a solution containing a biological substance, specifically a biopharmaceutical (such as antibody drugs, gene therapy drugs, nucleic acid drugs, virus vectors, etc.), a food ingredient or a beverage ingredient, and particularly a viral vector. The filter unit of the present invention comprises a separation functional layer "a" section having an average pore diameter Da, a separation functional layer "b" section having an average pore diameter Db, and a separation functional layer "c" section having an average pore diameter Dc, and an inlet for introducing a liquid to be treated into the separation functional layer "a" section, wherein the average pore diameters Da, Db, and Dc satisfy the following conditions A and B, and the separation functional layers are arranged in the order of the "a" section, the "b" section, and the "c" section from the inlet. 30μm≥Da>Db>Dc≥0.01μm 6≥Da/Db≥2.8