Nanoscale laser-induced breakdown spectroscopy imaging reveals chemical distribution with subcellular resolution

Understanding chemical compositions is one of the most important parts in exploring the microscopic world. As a simple method for elemental detection, laser-induced breakdown spectroscopy (LIBS) is widely used in materials, geological and life science fields. However, due to the long-existing limitation in spatial resolution, it is difficult for LIBS to play an analytical role in the field of micro-world. Herein, we first report a reliable nanoscale resolution LIBS imaging technique by introducing a sampling laser with a micro-lensed fiber. Through the emission enhancement using the double-pulse laser, we obtained the spectral signal from a sampling crater of less than 500 nanometers in diameter, and visualized the chemical distribution of the self-made grid sample, SIM chip and nano-particles in single cells. The relative limits of detection (RLODs) of In and absolute limits of detection (ALODs) of Al can reach 0.6% and 18.3 fg, respectively.