Free-Standing Membrane Nanopore Fabrication via Block Copolymer Self-Assembly
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Solution Overview
Problem
Current methods for manufacturing nanopores and free-standing membranes are inefficient, time-consuming, costly, and lack precise control over size and position, which hinders their application in biological sequencing, such as DNA and RNA analysis.
Innovation Solution
The use of directed self-assembly with block co-polymers to form nanopores and selective etching to create thin, free-standing membranes with precise control over nanopore size and position, allowing for efficient fabrication of well-controlled nanopores and membranes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current solid-state nanopore fabrication methods (tunneling electron microscope, focused ion beam, electron beam) are used, then nanopores can be formed, but manufacturing precision and control over size and position are insufficient
Solution Approach 1:
The patent employs block copolymer self-assembly where the polymers spontaneously organize into periodic structures with nanometer-scale precision. This self-organizing mechanism eliminates the need for complex external guidance systems while achieving uniform nanopore sizes and positions across the membrane, directly resolving the contradiction between manufacturing precision and fabrication ease.
Solution Approach 2:
The patent controls nanopore dimensions by adjusting block copolymer composition ratios, molecular weights, and assembly conditions. By changing these parameters, precise control over nanopore size (e.g., 5-50 nm diameter) and spacing is achieved without requiring complex fabrication equipment, thus improving manufacturing precision while maintaining ease of manufacture.
2Productivity
If current nanopore fabrication methods are used, then nanopores can be formed, but the process is time consuming and productivity is low
Solution Approach 1:
The patent performs preliminary self-assembly of block copolymers into the desired periodic pattern before any nanopore formation step. This pre-organized template guides subsequent nanopore creation, eliminating the need for time-consuming sequential positioning and drilling operations, thereby significantly improving productivity while reducing total fabrication time.
Solution Approach 2:
The patent replaces mechanical drilling or beam-based nanopore formation with a chemical self-assembly process. The block copolymer-directed self-assembly occurs under mild conditions and can be performed in parallel across entire membrane surfaces, dramatically increasing fabrication speed and productivity compared to sequential mechanical methods.
3Manufacturing precision
If manual free-standing membrane fabrication methods are used, then membranes can be produced, but the process is costly and cannot efficiently form membranes with optimum thinness
Solution Approach 1:
The patent controls membrane thickness by adjusting deposition parameters of the thin film material and the etch selectivity ratio between the sacrificial layer and the membrane material. This enables precise control over final membrane thickness (e.g., 10-100 nm) while maintaining high production efficiency through batch processing, resolving the contradiction between manufacturing precision and productivity.
Solution Approach 2:
The patent introduces a sacrificial sacrificial layer that mediates the membrane formation process. This intermediary layer enables controlled thinning of the membrane to optimal thickness while providing structural support during fabrication. The sacrificial layer is later selectively removed to create the final thin free-standing membrane, achieving both precision and efficiency.
4Reliability
If biological membranes and biological pores are used, then sequencing can be performed, but shelf life is limited and cold storage is required
Solution Approach 1:
The patent creates solid-state nanopores in stable, non-biological membranes that can be mass-produced and stored at room temperature for extended periods. These synthetic nanopores replace fragile biological membranes with durable solid-state structures that maintain their sequencing functionality without cold storage requirements, effectively treating the nanopore-containing membrane as a disposable, pre-prepared component.
Solution Approach 2:
The patent uses composite membrane structures combining inorganic or synthetic organic materials with controlled nanopore features. These composite materials provide both the structural stability for long-term storage and the precise nanometer-scale pore geometry needed for reliable sequencing performance, eliminating the shelf-life limitations of pure biological membranes.
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 enables rapid and cost-effective production of well-controlled nanopores and membranes, improving signal-to-noise ratios and enabling efficient DNA sequencing by allowing samples to pass freely through the nanopores, while the thin membranes provide high selectivity and resistance to saline solutions.
Implementation Method 1
forming one or more nanopores through directed self-assembly with block co-polymers
Implementation Method 2
selectively removing a portion of the highly etchable layer under the one or more nanopores to form a thin, free-standing membrane
Implementation Method 3
Electric current resulting from the conduction of ions through the nanopore is measured
Data Source
AI summary
Methods of manufacturing well-controlled nanopores using directed self-assembly and methods of manufacturing free-standing membranes using selective etching are disclosed. In one aspect, one or more nanopores are formed by directed self-assembly with block co-polymers to shrink the critical dimension of a feature which is then transferred to a thin film. In another aspect, a method includes providing a substrate having a thin film over a highly etchable layer thereof, forming one or more nanopores through the thin film over the highly etchable layer, for example, by a pore diameter reduction process, and then selectively removing a portion of the highly etchable layer under the one or more nanopores to form a thin, free-standing membrane.