Laser-induced breakdown spectroscopy for human and animal health: A review

Laser-Induced Breakdown Spectroscopy (LIBS) is in a stage of great vitality as an analytical technique. In the past few years, significant advances have been made in the area of LIBS applications to human and animal health. In this review, we have tried to capture their essence by describing briefly the methods used and highlight their key results. The review is structured in sections, each of which presents a different application: LIBS applied for the diagnosis of some diseases and the follow up of their therapy; LIBS as a tool to provide online feedback for laser surgery and dentistry; LIBS for the detection of exogenous and endogenous substances elements in humans and animals; LIBS applied for the detection of bacteria or viruses in bioaerosols or in clinical settings; and LIBS applied to assess animal health. In addition to applications, such as the analysis of hard calcified tissues and various biological materials analyzed as pellets or powders, this review reports on new research emerging trends likely to play an important role in the future development of the technique as well as in its penetration in the medical field. Three of these are: LIBS-based "liquid biopsy", that is, cancer diagnosis using fluids such as blood and urine deposited on solid substrates; the use of chemometrics for the discrimination of different tissues; and elemental imaging and mapping of trace elements and nanoparticles in soft tissues. Finally, the use of machine learning is playing an increasingly larger role in particular for sample classification.