Micro-Droplet-Based Calibration for Quantitative Elemental Bioimaging by LA-ICPMS
In this work, researchers from the University of Vienna present a novel – potentially groundbreaking – standardization technique for quantitative elemental bioimaging by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Gelatin-based micro-droplet standards (not to be confused with liquid microdroplets used for single-particle/cell standardization*) were produced by micro-spotting of exact standard volumes onto glass slides, resulting in droplet sizes of 200 μm in diameter. A low dispersion laser ablation setup and a TOFWERK icpTOF 2R were used for high-throughput LA-ICP-TOFMS enabling multi-elemental imaging at a rate of 200 pixels per second. Importantly, selective ablation of the gelatin micro-droplets needs to be achieved by selecting a laser energy density below the ablation threshold of the glass and above the thresholds of gelatin and the samples.
Analytical figures of merit of this new calibration approach, including limits of detection, precision, and accuracy, were assessed for platinum and other elements with biological key functions, such as phosphorus, copper, and zinc. The applicability of the technique was demonstrated on tumor tissue samples containing metal-based anticancer drugs but can certainly be extended to a range of other bioimaging applications.
*Note by TOFWERK