title: Dielectrophoresis-Assisted Raman Spectroscopy of Intravesicular Analytes on Metallic Pyramids.
abstract: Chemical analysis of membrane-bound containers such as secretory vesicles, organelles, and exosomes can provide insights into subcellular biology. These containers are loaded with a range of important biomolecules, which further underscores the need for sensitive and selective analysis methods. Here we present a metallic pyramid array for intravesicular analysis by combining site-selective dielectrophoresis (DEP) and Raman spectroscopy. Sharp pyramidal tips act as a gradient force generator to trap nanoparticles or vesicles from the solution, and the tips are illuminated by a monochromatic light source for concurrent spectroscopic detection of trapped analytes. The parameters suitable for DEP trapping were optimized by fluorescence microscopy, and the Raman spectroscopy setup was characterized by a nanoparticle based model system. Finally, vesicles loaded with 4-mercaptopyridine were concentrated at the tips and their Raman spectra were detected in real time. These pyramidal tips can perform large-area array-based trapping and spectroscopic analysis, opening up possibilities to detect molecules inside cells or cell-derived vesicles.
authors.affiliation: Department of Electrical and Computer Engineering, ‡Department of Biomedical Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Avijit
authors.initials: A
authors.lastname: Barik
authors.affiliation: Department of Electrical and Computer Engineering, ‡Department of Biomedical Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Sudhir
authors.initials: S
authors.lastname: Cherukulappurath
authors.affiliation: Department of Electrical and Computer Engineering, ‡Department of Biomedical Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Nathan J
authors.initials: NJ
authors.lastname: Wittenberg
authors.affiliation: Department of Electrical and Computer Engineering, ‡Department of Biomedical Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Johnson
authors.affiliation: Department of Electrical and Computer Engineering, ‡Department of Biomedical Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Oh
mesh_terms: D004586:Electrophoresis / Q000379:methods*; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D008856:Microscopy, Fluorescence; D011725:Pyridines / Q000032:analysis*; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D011725:Pyridines; C042861:4-thiopyridine; D006046:Gold