Gold-Coated Liposomes Encapsulating Signaling Molecules for Initiating Cellular Communication

G.V. Orsinger, M. Romanowski
University of Arizona, US

Keywords: liposomes, gold, cell signaling, cancer, optical trap

Summary:

To better understand the complex communication pathways of the tumor microenvironment, and therefore better design and develop therapies and diagnostics for cancers, experimental methods of probing cellular communication at a single to multi-cell level are needed. We previously presented plasmon resonant gold-coated liposomes for applications in cancer therapeutics and diagnostics. We have also demonstrated the application of these nanocapsules for selectively delivering fluorescent molecules to specific cellular components by optical manipulation. The high polarizability of the liposome’s unique gold pseudo-shell allows stable optical trapping for subcellular manipulation in the presence of cells. Here, we encapsulated the ubiquitous intracellular secondary cell signaling molecule inositol trisphosphate (IP3) within 100nm gold-coated liposomes and delivered them into the cytosol of a single cell with an optical trapping laser to initiate localized cell signaling. Upon optical injection of liposomal IP3 into a single ovarian carcinoma cell, we observed localized activation as reported by changes in Indo-1 fluorescence intensity. With established gap junctions between the injected cell and neighboring cells, we monitored propagation of this signaling to and through nearby cells. By combining optical trapping with gold-coated liposomes encapsulating signaling molecules, we present a unique in vitro tool for studying cell signaling within the tumor microenvironment.