title: Focal activation of cells by plasmon resonance assisted optical injection of signaling molecules.
abstract: Experimental methods for single cell intracellular delivery are essential for probing cell signaling dynamics within complex cellular networks, such as those making up the tumor microenvironment. Here, we show a quantitative and general method of interrogation of signaling pathways. We applied highly focused near-infrared laser light to optically inject gold-coated liposomes encapsulating bioactive molecules into single cells for focal activation of cell signaling. For this demonstration, we encapsulated either inositol trisphosphate (IP3), an endogenous cell signaling second messenger, or adenophostin A (AdA), a potent analogue of IP, within 100 nm gold-coated liposomes, and injected these gold-coated liposomes and their contents into the cytosol of single ovarian carcinoma cells to initiate calcium (Ca(2+)) release from intracellular stores. Upon optical injection of IP3 or AdA at doses above the activation threshold, we observed increases in cytosolic Ca(2+) concentration within the injected cell initiating the propagation of a Ca(2+) wave throughout nearby cells. As confirmed by octanol-induced inhibition, the intercellular Ca(2+) wave traveled via gap junctions. Optical injection of gold-coated liposomes represents a quantitative method of focal activation of signaling cascades of broad interest in biomedical research.
authors.affiliation: Department of Biomedical Engineering, University of Arizona , 1657 East Helen Street, Tucson, Arizona 85721, United States.
authors.forename: Gabriel V
authors.initials: GV
authors.lastname: Orsinger
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Williams
authors.forename: Marek
authors.initials: M
authors.lastname: Romanowski
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000737:chemistry; D002118:Calcium / Q000737:chemistry*; D002460:Cell Line; D045744:Cell Line, Tumor; D005260:Female; D017629:Gap Junctions; D006046:Gold / Q000737:chemistry; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D055095:Optics and Photonics; D010051:Ovarian Neoplasms / Q000473:pathology*; D015398:Signal Transduction; D020349:Surface Plasmon Resonance
chemical_list: D008081:Liposomes; C085029:adenophostin A; D006046:Gold; D015544:Inositol 1,4,5-Trisphosphate; D000241:Adenosine; D002118:Calcium