Modified M13 Phage Capture Surface for Specific CTC Isolation
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Solution Overview
Problem
The effective isolation of circulating tumor cells (CTCs) from whole blood is challenging due to the lack of a capturing surface with strong CTC-binding affinity and high off-target binding, which compromises the detection of CTCs and leads to non-specific adsorption of white blood cells (WBCs).
Innovation Solution
A modified M13 phage with a deformable surface containing an aptamer that specifically binds to cancer-related antigens is immobilized on a solid substrate, such as magnetic beads, enhancing CTC capture while reducing WBC adsorption through entropic discouragement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capturing surface with strong CTC-binding affinity is used, then CTC detection sensitivity is improved, but non-specific adsorption of white blood cells increases
Solution Approach 1:
The patent applies local quality by creating distinct functional zones on the capturing surface: regions with high-density aptamers for specific CTC binding, and regions with anti-fouling coatings to prevent non-specific WBC adsorption. This spatial differentiation of surface properties resolves the contradiction between high CTC capture efficiency and low non-specific binding.
Solution Approach 2:
The capturing surface uses composite materials combining aptamer-functionalized regions with anti-fouling coating regions. This composite structure enables simultaneous achievement of high CTC-binding affinity and resistance to non-specific WBC adsorption, directly resolving the technical contradiction.
2Strength
If aptamers are displayed on phage surface, then CTC binding affinity is improved, but phage production complexity increases
Solution Approach 1:
The patent employs self-service through the self-assembly capability of bacteriophage particles. The aptamer-displaying phages automatically organize and present aptamers on their surfaces during natural assembly processes, eliminating the need for complex external functionalization steps and reducing production complexity while maintaining high binding affinity.
Solution Approach 2:
The bacteriophage system serves multiple functions: it acts as a display platform for aptamers, provides structural stability, enables easy immobilization on surfaces, and facilitates high-throughput production. This multi-functionality reduces overall system complexity despite the sophisticated binding capability.
3Productivity
If high density of aptamers is used on capturing surface, then CTC capture efficiency is improved, but off-target binding increases
Solution Approach 1:
The patent implements local quality by creating heterogeneous surface regions: high-density aptamer zones for efficient CTC capture, and low-density or anti-fouling zones to minimize off-target binding. This spatial variation in aptamer density maintains high productivity while improving binding specificity.
Solution Approach 2:
The capturing surface employs dynamic aptamer distribution that can adjust local density based on binding conditions. This dynamic arrangement allows high aptamer availability for target CTCs while reducing non-specific interactions, resolving the contradiction between capture efficiency and binding specificity.
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 modified phage efficiently isolates CTCs with high specificity and purity, maintaining cell viability and reducing non-specific binding, thereby improving the sensitivity and accuracy of CTC detection.
Implementation Method 1
an aptamer that specifically binds to a cancer-related antigen
Implementation Method 2
reducing WBC adsorption through entropic discouragement
Implementation Method 3
The modified phage is immobilized on a solid substrate via a second capsid protein of the modified phage
Data Source
AI summary
The present disclosure relates to genetically engineered phage that bind to cancer cells. The genetically engineered phage can be used to isolate cancer cells, for example, circulating cancer cells, by binding to antigens specifically expressed on the surface of cancer cells. Thus, the present disclosure provides compositions, methods, and kits for improved cancer diagnosis that are useful for improved cancer treatment.