Influence of Sample Preparation Methods for Porcine Tissue: Calibration-Free LIBS for In Vivo Applications

Calibration-free laser-induced breakdown spectroscopy (CF-LIBS) has the advantage of eliminating the need for complex sample preparation. This study investigates the impact of various preparation techniques on porcine tissue. These methods include embedding the tissue in PBS or deionised water, and analysing untreated tissue or tissue that has been cut using liquid nitrogen. The results demonstrate that embedding samples does result in changes to the LIBS spectra. Minor deviations in the magnesium and sodium intensity ratios were observed in the skin. However, it should be noted that embedded samples may exhibit altered elemental signatures due to ionic exchange with the immersion medium, despite facilitating sample handling. It is important to note that the immediate measurement of untreated samples is critical, as post-mortem changes can lead to shifts in elemental concentrations. These findings show that CF-LIBS can be reliably performed on untreated biological samples, thus supporting its use in vivo diagnostics.