Harnessing LIBS for Next-Generation Diagnostic Platforms*

Microparticle-based assays provide excellent sensitivity and specificity for detecting a wide range of analytes that serve as disease biomarkers. LIBS has emerged as a powerful chemical elemental analysis technique, offering advantages such as requiring smaller sample volumes and minimal sample preparation compared to other methods. This study aims to develop LIBS-based assays using particles of different chemical elements to create element codes for labeling molecules of interest, forming a base for new diagnostics.

We present LIBS spectra results of microparticles made of SiO₂, TiO₂, Fe₃O₄, and Fe₂O₃, including Fe₃O₄ modified with streptavidin. Spectra of varying loads were measured on 0.2 μm pore size centrifuge filters with a SciAps Z-903 LIBS Analyzer. We identify Si, Ti, and Fe the spectral lines for each microparticle type with minimal interference even when among all the present chemicals present. We have plotted calibration curves using Python to determine the working range of concentrations with near-linear dependence of spectral line intensity on weight load. Regression techniques were employed to assess the accuracy of classifying microparticles of different compositions at various weight loads.

This research contributes to the development of sensitive and specific diagnostic tools using microparticle-based LIBS assays, potentially improving disease biomarker detection and expanding the applications of LIBS in medical diagnostics.