Quantum Photonic Micro/Nanolaser for Rapidly Assessing Overall Health of Cells and Organelles

Healthy respiration of cells and organelles requires a stable proton pump in the inner mitochondrial membrane to regulate the membrane potential and internal biomolecular composition. In stressed or diseased cells, these vital equilibrium conditions are altered. The changes can be quantified by laser-induced fluorescence and wide-angle light scattering, both influenced by mitochondrial morphology and membrane polarizability. Such techniques were used to image intra-cellular mitochondria in live tissue culture and isolated mitochondria (by biological fission and cell rupture) from both normal and transformed (cancer) mouse liver cells. Mitochondrial shape and membrane potential function were visualized by confocal laser scanning microscopy and correlated with ultra-dark field light scattering. The changes in mitochondrial adenosine triphosphate energy production were also quantified by UV absorption and UV luminescence excitation spectroscopy. Using the details gained from these microscopic and spectroscopic data, an intracavity micro/nanolaser spectrometer was designed to rapidly probe populations of flowing cells or isolated mitochondria. The biological micro/nanolaser (biocavity laser) emits coherent light from quantized optical modes defined by individual cells or mitochondria and provides unique spectral fingerprints. Statistical analyses of the population spectra successfully distinguished both whole cells and isolated mitochondria in the two cell types.