title: Investigation of biophysical mechanisms in gold nanoparticle mediated laser manipulation of cells using a multimodal holographic and fluorescence imaging setup.
abstract: Laser based cell manipulation has proven to be a versatile tool in biomedical applications. In this context, combining weakly focused laser pulses and nanostructures, e.g. gold nanoparticles, promises to be useful for high throughput cell manipulation, such as transfection and photothermal therapy. Interactions between laser pulses and gold nanoparticles are well understood. However, it is still necessary to study cell behavior in gold nanoparticle mediated laser manipulation. While parameters like cell viability or perforation efficiency are commonly addressed, the influence of the manipulation process on other essential cell parameters is not sufficiently investigated yet. Thus, we set out to study four relevant cell properties: cell volume and area, ion exchange and cytoskeleton structure after gold nanoparticle based laser manipulation. For this, we designed a multimodal imaging and manipulation setup. 200 nm gold nanoparticles were attached unspecifically to canine cells and irradiated by weakly focused 850 ps laser pulses. Volume and area change in the first minute post laser manipulation was monitored using digital holography. Calcium imaging and cells expressing a marker for filamentous actin (F-actin) served to analyze the ion exchange and the cytoskeleton, respectively. High radiant exposures led to cells exhibiting a tendency to shrink in volume and area, possibly due to outflow of cytoplasm. An intracellular raise in calcium was observed and accompanied by an intercellular calcium wave. This multimodal approach enabled for the first time a comprehensive analysis of the cell behavior in gold nanoparticle mediated cell manipulation. Additionally, this work can pave the way for a better understanding and the evaluation of new applications in the context of cell transfection or photothermal therapy.
authors.affiliation: Biomedical Optics Department, Laser Zentrum Hannover e.V., Hanover, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kalies
authors.affiliation: Biomedical Optics Department, Laser Zentrum Hannover e.V., Hanover, Germany.
authors.forename: Georgios C
authors.initials: GC
authors.lastname: Antonopoulos
authors.affiliation: Biomedical Optics Department, Laser Zentrum Hannover e.V., Hanover, Germany.
authors.forename: Mirko S
authors.initials: MS
authors.lastname: Rakoski
authors.affiliation: Biomedical Optics Department, Laser Zentrum Hannover e.V., Hanover, Germany.
authors.forename: Dag
authors.initials: D
authors.lastname: Heinemann
authors.affiliation: Biomedical Optics Department, Laser Zentrum Hannover e.V., Hanover, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Schomaker
authors.affiliation: Biomedical Optics Department, Laser Zentrum Hannover e.V., Hanover, Germany.
authors.forename: Tammo
authors.initials: T
authors.lastname: Ripken
authors.affiliation: Biomedical Optics Department, Laser Zentrum Hannover e.V., Hanover, Germany; Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hanover, Germany.
authors.forename: Heiko
authors.initials: H
authors.lastname: Meyer
mesh_terms: D000199:Actins / Q000378:metabolism; D020013:Calcium Signaling; D002460:Cell Line; D002470:Cell Survival; D006046:Gold / Q000737:chemistry*; D006696:Holography / Q000379:methods*; D007834:Lasers; D053768:Metal Nanoparticles / Q000737:chemistry*; D064847:Multimodal Imaging / Q000379:methods*; D061848:Optical Imaging / Q000379:methods*
chemical_list: D000199:Actins; D006046:Gold