Microfluidic Photolithography Arrays for Sub-10 Micron Spatial Barcoding
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Solution Overview
Problem
Existing methods for generating molecular arrays, such as nucleic acid arrays, struggle to achieve high-resolution spatial expression analysis of large numbers of genes or proteins simultaneously with stable attachment and precise positioning of nucleic acids on a substrate, particularly at small feature sizes below 10 microns, while maintaining high fidelity and throughput.
Innovation Solution
A method combining microfluidics and photolithography is used to synthesize nucleic acids in situ on a substrate by sequentially attaching oligonucleotides of at least four nucleotides in length through hybridization and ligation, guided by microfluidic channels and photolithography to achieve desired sequence diversity and precise spatial positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If base-by-base synthesis is used to generate molecular arrays, then precise spatial positioning can be achieved, but the manufacturing time and complexity increase significantly
Solution Approach 1:
The synthesis process is divided into two distinct stages: (1) microfluidic delivery stage where oligonucleotides are transported and attached to substrate locations, and (2) photolithography stage where light-directed deprotection and ligation occur. This segmentation allows parallel processing of multiple oligonucleotides simultaneously, reducing overall manufacturing time while maintaining precise spatial positioning through the photolithography mask system.
Solution Approach 2:
Oligonucleotides are pre-synthesized with protecting groups (e.g., photolabile groups at the 5' end) before being delivered to the substrate. This preliminary functionalization allows the oligonucleotides to be transported and positioned via microfluidics without requiring base-by-base assembly at the final location, significantly reducing on-substrate synthesis time while preserving spatial precision through controlled photodeprotection.
2Measurement precision
If feature sizes are reduced below 10 microns to achieve high resolution, then spatial expression analysis precision improves, but maintaining stable attachment and high fidelity becomes more difficult
Solution Approach 1:
The substrate surface is designed with location-specific features including position-specific oligonucleotide sequences and photolabile protecting groups that are selectively removed only at intended attachment sites. This local differentiation ensures that even at sub-10-micron feature sizes, each location maintains unique identification and stable attachment properties through complementary base pairing and covalent bonding, preventing cross-contamination and maintaining high fidelity.
3Adaptability or versatility
If oligonucleotides are sequentially attached through hybridization and ligation, then sequence diversity increases, but the number of synthesis steps increases
Solution Approach 1:
A single photolithography apparatus performs multiple functions: (1) selective photodeprotection of oligonucleotides at specific locations, (2) initiation of ligation reactions through UV activation, and (3) pattern transfer from digital masks to physical substrate. This multi-functional approach allows sequence diversity to be achieved through software-controlled mask patterns rather than complex physical reconfiguration, reducing device complexity while maintaining high sequence versatility.
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 the generation of molecular arrays with precise spatial information and improved resolution, allowing for high levels of multiplexing and efficient spatial encoding, reducing time and maintaining high fidelity of barcode incorporation.
Implementation Method 1
an immobilized nucleic acid can be synthesized by sequentially attaching oligonucleotides each of at least four nucleotides in length, e.g., through oligonucleotide hybridization and ligation
Implementation Method 2
irradiating the substrate to render oligonucleotide molecules in one or more regions on the substrate available for oligonucleotide attachment
Data Source
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AI summary
The present disclosure relates in some aspects to methods for manufacturing molecular arrays using a hybrid approach comprising microfluidics-based delivery and photolithographyguided oligonucleotide hybridization and ligation. In particular, the molecular arrays can be used for determining spatial patterns of abundance and/or expression of a biological target in a sample.