DESI-MSI Service

Creative Biostructure offers state-of-the-art desorption electrospray ionization mass spectrometry imaging (DESI-MSI) services, delivering high-resolution molecular imaging solutions to examine the complex chemical environments in biological tissues. DESI-MSI, a cutting-edge, non-destructive technique, allows in situ analysis of small molecules, uncovering vital spatial and quantitative information while minimizing sample preparation under atmospheric conditions. This maintains the analyte's original distribution, making it invaluable for research in biomarker discovery, pharmaceutical development, and metabolic studies.

Why Perform DESI-MSI?

DESI-MSI excels in rapidly visualizing the spatial distribution of metabolites and other small molecules in biological tissues without extensive sample preparation, preserving insights reflective of the tissue's natural state. It's particularly beneficial in identifying potential biomarkers, understanding drug distribution, and mapping metabolic pathways. The technique utilizes ionized solvent droplets to desorb molecules directly from the sample surface, allowing precise detection and analysis of target compounds. Providing both quantitative and spatial data, DESI-MSI maintains sample integrity, making it favored in applications requiring minimal alteration.

This mechanism involves high-speed ionized solvent droplets that desorb analytes from the sample surface, transporting them as gaseous droplets to the mass spectrometer inlet for analysis. Different spray solvents can be used depending on the polarity of the target metabolite. DESI-MSI is primarily applied in medical research for efficient biomarker discovery, capable of revealing structural, content, and spatial distribution details of numerous metabolites and drugs directly from biological tissues. However, DESI faces limitations in molecular ionization dependent on solvent composition and is restricted by a spatial resolution generally around 200 µm, which is lower compared to other methods like secondary ion mass spectrometry (SIMS) and matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS).

Figure 1. The ionization principle for DESI-MSI. (Hou Y, et al., 2023)

Our DESI-MSI Service Procedure

Our DESI-MSI service can detect substances of various molecular weights without bias. It supports not only dual ion detection mode but also single ion detection mode, providing higher selectivity and more flexible resolution options, providing detailed molecular distribution maps while maintaining high sensitivity.

1. Consultation and Project Planning: Each DESI-MSI project begins with an in-depth consultation to fully understand the research goals. Our team collaborates closely with clients to customize services, discuss specific sample preparation needs, and set clear expectations for project deliverables and timelines.
2. Sample Delivery: To ensure molecular integrity, store samples at -80°C and ship them on dry ice. This approach keeps the samples stable during transit, preventing any degradation prior to analysis.
3. Sample Preparation and Optimization: Electrospray ionization is conducted directly on the sample surface using a high-pressure solvent spray. Our experts manage all aspects of sample preparation, minimizing alterations while optimizing for DESI ionization efficiency.
4. MSI Experiment: During analysis, charged droplets from the solvent spray interact with the sample surface to release target analytes as gaseous ions. Our high-resolution DESI-MSI equipment, operating under atmospheric pressure, then captures both spatial and quantitative analyte data, providing precise molecular imaging across the entire sample.
5. Data Collection: The generated ions are detected by the mass spectrometer, creating detailed images that reveal the molecular distribution throughout the sample. This step yields critical spatial information that can inform various research insights.
6. In-depth Data Analysis: Our team performs a comprehensive analysis on the collected data to extract valuable information, including quantitative insights and molecular distribution patterns. This detailed examination provides clients with interpretable data for advanced research applications.
7. Result Summary: we provide clients with a comprehensive project report, complete with raw data and high-resolution molecular distribution images. This final documentation is structured to support in-depth interpretation and application of the findings.

Sample Requirements

To ensure optimal results, we request that all samples meet specific criteria prior to DESI-MSI analysis:

• Tissue Type: The sample should be fresh-frozen or formalin-fixed paraffin-embedded (FFPE) tissue sections. Fresh samples are preferable as they preserve the original metabolite distribution. Samples are stored at -80°C and shipped on dry ice.
• Sample Thickness & Surface Condition: If the samples you provide are tissue sections, they should be within the range of 3-20 µm in thickness for precise imaging and analysis. Smooth, clean surface sections are ideal for optimal droplet interaction with the sample's surface.
• Environmental Stability: Samples that are stable under ambient conditions are recommended, as DESI-MSI operates without the need for vacuum environments.

Our team can provide guidance on any sample preparation steps that may be required, ensuring that samples are preserved, processed, and mounted to achieve high-quality results.

Figure 2. Our DESI-MSI service workflow. (Creative Biostructure)

Why Choose Creative Biostructure?

• Versatile Resolution: Our DESI-MSI platform accommodates various resolutions, catering to diverse study needs, from broad mapping to detailed molecular analysis.
• Detection Flexibility: We provide dual-ion and single-ion detection options, adaptable for detecting a wide array of analytes and tailored ion selection for specific research goals.
• Technical Expertise: Our seasoned team offers comprehensive support, from project planning and optimization to data analysis.
• Prompt Client Service: We emphasize efficient communication, ensuring swift responses to inquiries and requests to maintain project timeliness.

Frequently Asked Questions

• What types of samples are suitable for DESI-MSI?

  DESI-MSI is well-suited for biological tissue sections, particularly thin, frozen tissue samples. Samples should be prepared to preserve their surface chemistry, as DESI-MSI is sensitive to molecular changes on the sample surface.

• How does DESI-MSI compare to other MSI techniques?

  DESI-MSI stands out for its non-destructive and in situ imaging capabilities, making it ideal for applications where sample preservation is essential. Although it has lower spatial resolution compared to SIMS or MALDI-MS, DESI-MSI's minimal sample preparation and atmospheric pressure operation make it highly efficient and versatile.

• Can DESI-MSI be used for quantitative analysis?

  Yes, DESI-MSI can provide both qualitative and quantitative data. By correlating signal intensities with concentration levels, DESI-MSI can yield quantitative information about metabolite content and distribution within tissues.

• Do you provide data analysis support for your service?

  Yes, our service includes comprehensive data analysis support. We provide image generation, molecular distribution map drawing, and detailed statistical analysis reports to help you interpret your experimental results.

• Does your DESI-MSI service support customized experimental design?

  We provide customized experimental design services. Based on your specific research needs, we can adjust sample processing, matrix selection, and imaging parameters to ensure the best experimental results.

Creative Biostructure provides high-quality DESI-MSI services based on professional technical knowledge to meet the diverse needs of our customers. If you are interested in our services, please contact us for a detailed quote.

Ordering Process

References

1. Hou Y, Gao Y, Guo S, et al. Applications of spatially resolved omics in the field of endocrine tumors. Frontiers in Endocrinology. 2023. 13: 993081.
2. Kajimura M, Nakanishi T, Takenouchi T, et al. Gas biology: tiny molecules controlling metabolic systems. Respiratory Physiology & Neurobiology. 2012. 184(2): 139-148.
3. Chen K, Baluya D, Tosun M, et al. Imaging mass spectrometry: a new tool to assess molecular underpinnings of neurodegeneration. Metabolites. 2019. 9(7): 135.