title: Laser-induced fast fusion of gold nanoparticle-modified polyelectrolyte microcapsules.
abstract: In this study we investigated the effect of laser-induced membrane fusion of polyelectrolyte multilayer (PEM) based microcapsules bearing surface-attached gold nanoparticles (AuNPs) in aqueous media. We demonstrate that a dense coating of the capsules with AuNPs leads to enhanced light absorption, causing an increase of local temperature. This enhances the migration of polyelectrolytes within the PEMs and thus enables a complete fusion of two or more capsules. The encapsulated substances can achieve complete merging upon short-term laser irradiation (30 s, 30 mW @ 650 nm). The whole fusion process is followed by optical microscopy and scanning electron microscopy. In control experiments, microcapsules without AuNPs do not show a significant capsule fusion upon irradiation. It was also found that the duration of capsule fusion is affected by the density of AuNPs on the shell - the higher the density of AuNPs the shorter the fusion time. All these findings confirm that laser-induced microcapsule fusion is a new type of membrane fusion. This effect helps to study the interior exchange reactions of functional microcapsules, micro-reactors and drug transport across multilayers.
authors.affiliation: Key Lab for Microsystems and Microstructure Manufacturing, Micro/Nanotechnology Research Centre, Harbin Institute of Technology, Yi KuangJie 2, Harbin, 150080, China. qianghe@hit.edu.cn.
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Wu
authors.forename: Johannes
authors.initials: J
authors.lastname: Frueh
authors.forename: Tieyan
authors.initials: T
authors.lastname: Si
authors.forename: Helmuth
authors.initials: H
authors.lastname: Möhwald
authors.forename: Qiang
authors.initials: Q
authors.lastname: He
mesh_terms: D002214:Capsules / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D007834:Lasers; D053768:Metal Nanoparticles / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D013696:Temperature
chemical_list: D002214:Capsules; D004573:Electrolytes; D006046:Gold