Solid Phase Microextraction Sampling: A Probe-based Technique for Sample Extraction from Graft Tissues
JoVE Encyclopedia of Experiments
Cancer Research
0 views • 3:42 min • April 30th, 2023
Long-term storage of an organ graft affects its metabolic profile, which is an indicator of organ function and early-stage organ rejection.
To isolate these metabolites, begin by taking a thin solid-phase microextraction or SPME probe coated with a biocompatible sorbent. Immerse the probe in a hydroalcoholic cleaning solution to hydrate the coated sorbent and loosen up any bound impurities.
Agitate the probe to remove the impurities. Next, place the probe in an activation solution and agitate again. Chemicals in the activation solution modify the probe surface, enhancing its adsorption potential. Rinse the probe with water and sterilize it to remove microbial contaminants.
Now, insert the sterile and activated probe into the organ graft such that the tissue matrix covers the entire sorbent surface. The sorbent material attracts free polar and non-polar metabolites from the graft, enabling adsorption onto its surface. Retract the probe and rinse it with water to remove any residual tissue.
Then, place the probe into a desorption solution, which interacts with the adsorbed metabolites. Agitate the probe to separate and solubilize the captured metabolites into the desorption solution. Finally, remove the probe and process the resultant metabolite mixture for subsequent analysis.
Start by preparing a preconditioning mixture composed of 1 to 1 methanol and water. Pipette 1 milliliter of the solution into each 2-milliliter glass vial and place one probe in each vial. Agitate the vials on a vortex agitator at 1,200 rpm for 1 hour. Then, rinse the probes with LC-MS grade water and sterilize them according to the standard surgical sterilization protocol or in sterile processing department.
When ready to extract the sample, open the sterile packaging and insert two probes directly into the kidney cortex for 10 minutes per time point, making sure that the entire length of the coating is covered by the tissue matrix. Make sure to keep track of the time of sampling for each probe. Retract the probe by pulling it out from the tissue and immediately rinse the coating with LC-MS grade water to remove any remaining blood, making sure to rinse away from the surgical site.
To transport the probes, place them in separate vials and close them. Then, place the vials in a box filled with dry ice or liquid nitrogen. Store the samples at negative 80 degrees Celsius or immediately proceed with desorption.
Prepare a desorption solution composed of acetonitrile and water for metabolomic analysis and another composed of isopropanol and methanol for lipidomic analysis. Add 100 microliters of the solution to inserts in the 2-milliliter labeled vials and place one probe in each vial. Agitate the vials at 1,200 rpm for 2 hours. Then, remove the probes from the vials and proceed with LC-MS analysis.
Overview
This study investigates the impact of long-term organ graft storage on its metabolic profile, which is crucial for assessing organ function and potential rejection. The methodology involves the use of solid-phase microextraction (SPME) to isolate metabolites from the organ graft.
Key Study Components
Area of Science
- Neuroscience
- Organ transplantation
- Metabolomics
Background
- Organ grafts undergo metabolic changes during storage.
- Metabolites serve as indicators of organ health and rejection.
- SPME is a technique used for metabolite extraction.
- Understanding these changes can improve transplant outcomes.
Purpose of Study
- To analyze the metabolic profile of organ grafts post-storage.
- To develop a reliable method for metabolite extraction.
- To assess the implications of metabolic changes on organ function.
Methods Used
- Preparation of SPME probes with biocompatible sorbents.
- Hydration and activation of probes to enhance adsorption.
- Insertion of probes into organ grafts for metabolite capture.
- Desorption of metabolites for subsequent analysis using LC-MS.
Main Results
- Successful isolation of metabolites from organ grafts.
- Identification of key metabolic changes linked to storage duration.
- Demonstrated effectiveness of SPME in metabolomic studies.
- Insights into the relationship between metabolism and organ rejection.
Conclusions
- Metabolic profiling is essential for understanding organ graft viability.
- SPME is a valuable tool for metabolite extraction in transplantation research.
- Further studies are needed to correlate metabolic changes with clinical outcomes.
Frequently Asked Questions
Executive Industry Relevance
Solid phase microextraction (SPME) enables direct, minimally invasive sampling of metabolites from graft tissues, supporting objective assessment of organ quality prior to transplantation. This probe-based approach provides actionable metabolic and lipidomic data, informing early go/no-go decisions and reducing biological uncertainty in organ selection workflows. Integrating SPME-derived analytics enhances predictive confidence at a critical inflection point in the transplant pipeline.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables direct interrogation of tissue metabolic state for functional assessment.
- Supports biological de-risking by revealing early markers of organ viability or rejection.
- Provides quantitative data to inform target validation in organ preservation research.
Screening & Assay Development
- Facilitates preparation of validated tissue samples for downstream metabolomic and lipidomic assays.
- Improves assay reproducibility by standardizing metabolite extraction from intact tissues.
- Enables scalable, high-throughput screening of organ quality using consistent probe-based sampling.
Translational & Preclinical Research
- Aligns metabolic profiling with disease-relevant endpoints in transplantation models.
- Supports translational continuity by linking pre-harvest tissue state to post-transplant outcomes.
- De-risks advancement decisions by providing mechanistic insight into graft function.
Pipeline & Workflow Integration
SPME sampling integrates at the interface of organ procurement and analytical characterization, bridging early discovery with translational assessment in transplantation research.
- Discovery Biology: Enables hypothesis testing on metabolic shifts during organ storage and handling.
- Screening: Provides standardized, reproducible extraction for quantitative metabolite and lipid analysis.
- Analytics: Delivers LC-MS-ready samples for robust comparison of tissue metabolic profiles.
- Translational Research: Connects preclinical tissue sampling to clinical biomarker development in transplantation.
- Enterprise Reuse: Establishes a reusable, minimally invasive sampling platform for diverse tissue types and studies.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence in organ viability and function.
- Operational Value: Standardizes tissue sampling and enhances reproducibility across studies.
- Strategic Value: Supports informed go/no-go decisions and reduces late-stage biological risk in transplantation pipelines.
- Portfolio Impact: Enables risk-adjusted prioritization of organs and protocols for further development.
Implementation Considerations
- Requires expertise in probe handling, tissue sampling, and LC-MS analytics.
- Demands access to sterile processing and controlled storage infrastructure.
- Necessitates cross-team standardization of sampling timing and probe activation.
- Adaptable to various tissue types with protocol optimization for each matrix.
- Dependent on rigorous sample tracking and contamination control during extraction and transport.
Biopharma FAQs
Normothermic Ex Vivo Kidney Perfusion for the Preservation of Kidney Grafts prior to Transplantation
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Last updated: 29 August 2026