The field of spatial transcriptomics has significantly advanced our ability to investigate gene expression while maintaining the spatial organization of cells within tissues. This breakthrough has opened new frontiers in biomedical research, allowing scientists to study gene activity within its native microenvironment rather than in isolation.

Among the most cutting-edge technologies driving this revolution is 10x Genomics Visium—a powerful platform that enables high-resolution mapping of transcriptomic landscapes across tissue sections. By seamlessly integrating next-generation sequencing (NGS) with spatially barcoded capture slides, Visium provides an unprecedented level of detail, allowing researchers to analyze gene expression patterns in their precise anatomical context.

This capability is invaluable for studying complex biological processes, such as tumor microenvironments, neural circuits, and developmental biology, where cellular interactions and spatial organization play a fundamental role. Visium not only facilitates a deeper understanding of how genes function within tissues but also aids in identifying biomarkers and therapeutic targets with potential clinical applications.

In this comprehensive exploration, we will delve into the core principles of 10x Genomics Visium, breaking down its workflow, the underlying technology that powers it, and the transformative applications it brings to modern biomedical research.

10x Genomics Visium is a spatial transcriptomics platform designed to analyze mRNA expression while maintaining the spatial organization of tissue samples. It works by capturing mRNA from a tissue section and linking each transcript to its original spatial location, enabling the creation of spatially resolved transcriptomic maps.

Step-by-Step Workflow

1-Tissue Preparation and Fixation

• Fresh frozen or FFPE (formalin-fixed, paraffin-embedded) tissue sections are mounted onto Visium Spatial Gene Expression slides, which contain thousands of spatially barcoded oligonucleotide probes.
• Tissue integrity is preserved using fixation and permeabilization steps.

2-Staining and Imaging

• Tissue sections are stained (typically with H&E staining) to provide morphological context.
• High-resolution imaging is performed before transcriptomic analysis to allow correlation between gene expression and tissue structure.

3-mRNA Capture and Reverse Transcription

• The slide contains spatially barcoded oligonucleotides in an array of defined spots (~55µm in diameter).
• Permeabilization enables mRNA release, which binds to the barcode-linked probes.
• Reverse transcription occurs, generating complementary DNA (cDNA) while incorporating spatial barcodes.

4-Library Preparation and Sequencing

• The cDNA undergoes amplification and library preparation.
• The prepared libraries are sequenced using next-generation sequencing (NGS) platforms to identify gene expression patterns.
• Each transcript is tagged with a spatial barcode, allowing mapping back to specific locations in the tissue.

5-Data Analysis and Visualization

• The sequencing data is processed using 10x Genomics’ Space Ranger software, aligning reads to the reference genome and assigning them to spatial locations.
• The final results can be visualized using Loupe Browser, which overlays gene expression data onto tissue images, revealing spatially resolved transcriptomic patterns.

Core Advantages of 10x Genomics Visium

-High Spatial Resolution: The Visium slides contain thousands of barcoded spots, each covering an area of 50-100 cells, preserving spatial context.

-Compatibility with Morphological Imaging: Enables integration with histological stains (H&E) or immunofluorescence for direct tissue visualization.

-Broad Tissue Compatibility: Works with both fresh frozen and FFPE tissue sections, making it suitable for archival samples.

-Comprehensive Transcriptome Analysis: Detects thousands of genes in a single experiment, providing deep insights into tissue heterogeneity.

1. Cancer Research: Identifies tumor microenvironment interactions, characterizing heterogeneity in tumors.
2. Neuroscience : Maps gene expression in brain tissues to study neurodevelopment and neurodegenerative diseases.
3. Developmental Biology : Tracks gene expression across different tissue layers to understand organ development.
4. Immunology : Examines immune cell localization and response in tissues.
5. Regenerative Medicine : Investigates cellular dynamics in tissue repair and regeneration.

10x Genomics Visium has transformed spatial transcriptomics by allowing researchers to explore the complex relationship between gene expression and tissue architecture. By integrating sequencing with spatial barcoding, it provides an unprecedented level of resolution for studying biological processes in health and disease. As technology advances, spatial transcriptomics is poised to become an essential tool in precision medicine, biomarker discovery, and fundamental biological research.