The Single-probe can be used as microscale sampling device to extract analytes for direct MS analysis. In a study by Sun et. al, the integration of the Micro-funnel, which was implanted into a spheroid, with the Single-probe provided an innovative approach to analyze extracellular metabolites in live multicellular tumor spheroids (Figure ). This work focused on understanding the effects of anticancer drug treatments in the tumor microenvironment . This technique is particularly valuable for capturing undiluted extracellular compounds inside single spheroids, a critical area due to its unique microenvironment and potential for harboring drug-resistant cells.