Regulation of Cellular Molecular Signaling by Light (Invited Paper)
Laser technology has been promoting various microscopy methods and thus making great progresses in life science. Further than contribution to ``seeing is believing'', lasers have also demonstrated their capacity of manipulating cells and even molecular signaling. Specifically, with advances of lasers and combination with other techniques, recent reports show that cell calcium ion, a universal intra- and inter-cellular messenger, can be modulated by lasers at different levels of biological organization from organelle to tissue. It is very encouraging that laser irradiation can activate or control plenty of corresponding cell processes and functions by regulating cell calcium signaling pathways, with promising potential in both scientific research and clinical application. In this paper, optical techniques for regulation of cell calcium signaling are specifically reviewed. Most methods need exogenouschemicals or genetic materials to convert incident photon into stimulation that cells can response with specific molecular dynamics. The only all-optical approach is achieved by nonlinear excitation with femtosecond laser, despite lack of specificity and controllability, providing possibility of a totally noninvasive method without any biochemical materials and thus further potential clinical application in human beings. The developments and techniques of those methods are introduced and explained, with analysis on their properties and current challenges. Potential applications and prospective development are also discussed. Researchers on biophotonics and related biological fields can benefit from this review. It also provides a systematic reference to doctors and researchers who are working on practical application of those methods.